© Crown copyright 2020 · 2020. 11. 25. · national monitoring schemes1 [Footnote 1: See ‘Main notes’ at the end for more details of the surveys sources used]. Trends in bird

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Acknowledgements:

All photographs are by Natural England and are sourced from their flickr account. Starting

from the top left the images are: a reed bunting (by Bob Silver); a bullfinch (by Bob Silver);

a cormorant (by Dave Harrison); a redshank (by Andrew Sloan); a goldeneye (by

Aidanos); and a sanderling (by Andrew Sloan).

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Contents

England executive summary ................................................................................................ 7

Why monitor bird populations? ............................................................................................ 8

Understanding the bird population indices ........................................................................... 8

Assessing trends ................................................................................................................. 9

1. Native breeding wild bird populations in England .......................................................... 11

2. Breeding farmland bird populations in England ............................................................. 13

3. Breeding woodland bird populations in England ............................................................ 17

4. Breeding water and wetland bird populations in England .............................................. 21

5. Breeding seabird populations in England ....................................................................... 28

6. Wintering waterbird populations in England ................................................................... 31

Main notes: methodological detail, limitations of the indicators and further information ..... 34

Annex A: Trends in bird species, by habitat group, in England .......................................... 36

Annex B Frequently asked questions ................................................................................ 51

England executive summary The combined all-species index has changed relatively little compared with around 45 years

ago, however, this masks considerable flux, with some species increasing and some species

decreasing. Changes by habitat are summarised below; unsmoothed figures are used for

comparison with the latest year; and smoothed indices to the penultimate year are used to

assess change over long or short-term trends as they reduce short-term peaks and troughs.

Latest year: 2019…

• the unsmoothed all-species index in England was 6% lower than in 1970.

• the unsmoothed farmland bird index was 42% of its 1970 value.

• the unsmoothed woodland bird index was 27% below its 1970 value.

• the unsmoothed water and wetland bird index was 1% above its 1975 value.

• the unsmoothed seabird index was 11% above its 1986 valuea.

• the unsmoothed wintering waterbird index was 76% higher in 2017/18 than in

1975/76, the index peaked in the second half of the 1990s and has declined since.

Table showing long and short-term smoothed trends at a glance for England

Index Long-term trend,

1970 to 2018

Short-term trend,

2013 to 2018

All bird species -8% (not significant) -1% (not significant)

Farmland birds -59% (significant) -6% (significant)

Woodland birds -28% (significant) -6% (significant)

Water and wetland birds (index started 1975) 4% (not significant) 1% (not significant)

Seabirdsa (index started 1986) 9% (not significant) 4% (not significant)

Wintering waterbirdsb (index started 1975/76,

change to 2017/18)

81% -6%

a The seabirds indicator is an unsmoothed trend as no smoothed trend is available

b Data from surveys of wintering waterbirds are based largely on full counts at colonies or wetland and

coastal sites of markedly varying size. This means that bootstrapping methods cannot be applied reliably

and hence trends for these groups are currently presented without confidence intervals.

Why monitor bird populations?

Bird populations have long been considered to provide a good indication of the broad state

of wildlife in England. This is because they occupy a wide range of habitats and respond to

environmental pressures that also operate on other groups of wildlife. In addition, there are

considerable long-term data on trends in bird populations, allowing for comparison

between trends in the short term and long term. Because they are a well-studied

taxonomic group, drivers of change for birds are better understood than for other species

groups, which enables better interpretation of any observed changes. Birds also have

huge cultural importance and are highly valued as a part of England’s natural environment

by the general public. However, the bird indicators presented in this publication are not

intended, in isolation, as indicators of the health of the natural environment more widely.

It is not practical to determine changes in the actual number of birds for each species in

England each year, but it is possible and more reliable to assess their status by calculating

relative change, based on counts on representative sample plots surveyed as part of

national monitoring schemes1 [Footnote 1: See ‘Main notes’ at the end for more details of the surveys

sources used].

Trends in bird populations are used by policy makers, government agencies and non-

governmental organisations as part of the evidence base with which to assess the effects

of any kind of environmental management, such as agricultural practices, on bird

populations. The trends are also used to assess the effectiveness of environmental

interventions intended to address declines, such as agri-environment schemes targeted at

farmland birds.

Understanding the bird population indices

Individual bird species population trends, based on carefully designed surveys undertaken

largely by expert volunteers, are calculated as a series of annual indices. These relate the

population in a given year to a ‘baseline’ – the first year that data are available – which is

given a value of 100. Thereafter, the index is expressing the population as a percentage of

this ‘baseline’.

This annual Defra National Statistics Release presents data trends up to 2019 in

populations of common birds (species with a population of at least 300 breeding pairs) that

are native to, and breed in, England, with trends overall as well as for 4 main habitat

groups (see Annex A for a list of birds in each group). The release also presents trends for

wintering waterbirds, some of which also breed in England.

1 See ‘Main notes’ at the end for more details of the surveys sources used.

The charts presented combine individual species indices2 into a single indicator to provide

an overall trend for each group mentioned above [Footnote 2: Using a geometric mean - an

average calculated by multiplying a set of index values and taking the nth root, where n is the number of

index values. More information can be found in Introduction to the Wild Birds Population Indicator]. The

indices are considered to give reliable medium to long-term trends, but strong reliance

should not be attached to short-term changes from year to year.

Assessing trends

Two trends are referred to in the text: the unsmoothed indices show year-to-year

fluctuation in populations, reflecting the observed changes in the survey results, and

smoothed trends3, which are used to formally assess the statistical significance of change

over time [Footnote 3: There are currently no smoothed trends available for seabirds]. Smoothed

trends4 are used for both long and short-term assessments as they reduce the short-term

peaks and troughs resulting from, for example, year-to-year weather and sampling

variations as well as good or bad breeding seasons [Footnote 4: See analytical methods on BTO

website (www.bto.org/birdtrends2011/methodology.htm) Fewster et al. 2000. Ecology 81: 1970 to 1984].

The most recent year of data in the smoothed indices, i.e. 2019 in this update, is likely to

change due to the smoothing process following the inclusion of 2020 data in next year’s

update. As a result, it is not appropriate to make assessments that include this last inter-

year interval. Where results from the smoothed indices are quoted, this is clearly indicated.

These trends are based on estimates from surveys. Smoothed trends are presented with

95% confidence intervals (CI), which are a measure of the precision of these survey

estimates: a 95% CI means users can be 95% confident that the true value of an indicator

in a given year falls within the confidence interval around it. The width of confidence

intervals varies between habitat indicators it is influenced by the number of species in each

indicator and the precision of the individual species trends that make up the indicator. For

the indicators derived from species trends that cannot be statistically evaluated by this

method (e.g wintering waterbirds and all-species) a threshold of 5% is used to evaluate the

significance of the change.

Throughout this release, assessment periods are referred to as:

• ‘Long-term’ – an assessment of change since the earliest date for which data are

available; this varies among indicators and among individual species.

• ‘Short-term’ – an assessment of change over the latest 5 years for which data are

available.

2 Using a geometric mean - an average calculated by multiplying a set of index values and taking the nth root,

where n is the number of index values. More information can be found in Introduction to the Wild Birds

Population Indicator. 3 There are currently no smoothed trends available for seabirds. 4 See analytical methods on BTO website (www.bto.org/birdtrends2011/methodology.htm) Fewster et al. 2000.

Ecology 81: 1970 to 1984.

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/283005/A_Brief_Introduction_to_the_Wild_Birds_Populations_Indicator.pdf

http://www.bto.org/birdtrends2010/methodology.htm




Annex A shows long-term and short-term assessments for each individual bird species.

Alongside the overall index, the percentage of species within each indicator that have

increased or decreased in the long term and in the short term is also shown. This is based

on the average rate of annual change over both assessment periods, categorised by how

much the population would change if that annual change continued for 25 years. The bar

chart illustrates the percentage of species falling into each category:

Strong increase: population increase of 100% or more

Weak increase: more than 33% but less than 100% increase

Little change: between a 25% decrease and a 33% increase

Weak decline: less than 50% but greater than 25% decrease

Strong decline: population decrease of 50% or more.

These thresholds are asymmetrical to represent symmetrical proportional change in an

index, i.e. the opposite of a 50% decline is a doubling (a 100% increase), not a 50%

increase. These thresholds are derived from those used in the Birds of Conservation

Concern5 status assessment for birds in the UK [Footnote 5: See the BTO website

(https://www.bto.org/our-science/projects/birdtrack/bird-recording/birds-conservation-concern)].

The bird population indices have been compiled in conjunction with the Royal Society for

the Protection of Birds (RSPB), the British Trust for Ornithology (BTO), the Wildfowl and

Wetlands Trust (WWT) and the Joint Nature Conservation Committee (JNCC).

5 See the BTO website (https://www.bto.org/our-science/projects/birdtrack/bird-recording/birds-conservation-

concern)

http://www.bto.org/volunteer-surveys/birdtrack/bird-recording/birds-conservation-concern

http://www.bto.org/volunteer-surveys/birdtrack/bird-recording/birds-conservation-concern

https://www.bto.org/our-science/projects/birdtrack/bird-recording/birds-conservation-concern



1. Native breeding wild bird populations in England

In 2019, the all-species index in England, based on the aggregated population trends of

118 breeding species, was 6% below its 1970 value.

The indicator declined between the late 1970s and the late 1980s, driven mostly by

declines in woodland and farmland birds, the all-species index has since levelled off and

showed little change (-1% and not significant) in the short term between 2013 and 2018.

Figure 1: Breeding wild birds in England, 1970 to 2019

Notes:

i) figures in brackets show the number of species,

ii) graph shows unsmoothed trend (dashed line) and smoothed trend (solid line) with its 95% confidence

interval (shaded area).

Long term

Within the index, 31% of the 118 species increased, 35% showed little change and 32%

declined between 1970 and 2018. It was not possible to calculate a long-term trend for 3

species because their data series start in 2005 or later.

Short term

Over the short-term period between 2013 and 2018, 30% of species increased, 34%

showed little change and 36% declined.

Species breakdown

The all-species index is comprised of 118 species of birds, all widespread species with

populations of at least 300 breeding pairs for which there are sufficient data to calculate a

trend. Species trends within this index vary widely, from those increasing several-fold (e.g.

buzzard, Cetti’s warbler, great spotted woodpecker and collared dove) to those having

declined to less than a tenth of their 1970 numbers (turtle dove, willow tit, grey partridge,

lesser redpoll, spotted flycatcher and tree sparrow). The main patterns and drivers of

change are best considered by looking at the indices of species grouped by habitat below

in Figure 1a and described in greater detail in the following chapters.

Figure 1a: Populations of wild birds in England by habitat, 1970 to 2019

2. Breeding farmland bird populations in England

Farmland refers to the large proportion of England which is devoted to agriculture and

consists of arable land and pastures. Farmland also provides semi-natural habitats such

as hedgerows and field margins that provide food and shelter to birds.

In 2019 the England farmland bird index was 42% of its 1970 value. The majority of this

decline occurred between the late 1970s and early 1980s and was largely due to the

negative impact of rapid changes in many farmland management practices during this

period. The decline has continued at a slower rate more recently; the smoothed index

decreased significantly by 6% between 2013 and 2018.

Figure 2: Breeding farmland birds in England, 1970 to 2019

Notes: i) figures in brackets show the number of species,



Long term

Since 1970, 21% of species showed a weak increase, 21% showed little change and 58%

showed either a weak or strong decline.

Short term



Factors affecting farmland bird populations

The large declines in the abundance of many farmland birds have a number of known and

potential causes. For a large part, declines have been caused by the changes in farming

practices that have taken place since the 1950s and 60s, such as the loss of mixed

farming, a move from spring to autumn sowing of arable crops, change in grassland

management (e.g. a switch from hay to silage production), increased pesticide and

fertiliser use, and the removal of non-cropped features such as hedgerows. The rate of

these changes, which resulted in the loss of suitable nesting and suitable feeding habitats,

and a reduction in available food, was greatest during the late 1970s and early 1980s, the

period during which many farmland bird populations declined most rapidly.

Some farming practices continue to have negative impacts on bird populations, but most

farmers can and do take positive steps to conserve birds on their land. In particular, a

number of incentive schemes encourage improved environmental stewardship in farming,

with some measures specifically designed to help stabilise and recover farmland bird

populations. These include the provision of over-wintered stubbles and planted wild bird

crop covers to provide seed in the winter, uncropped margins on arable fields and

sympathetic management of hedgerows. There is growing evidence that such action can

deliver local recoveries in farmland bird populations and thus, if delivered at appropriate

scale, wider recovery. Changes in numbers experienced by some species may, to a lesser

extent, be further driven by other pressures. For example, there is evidence of an adverse

impact from disease for some species, most notably greenfinch.

For more information about the evidence for this indicator, see the evidence statement

‘Annex 1.03 Evidence Statement for C5a Farmland Birds’.

Species breakdown

The farmland bird index is comprised of 19 species. The long-term decline of the farmland

indicator for England has been driven mainly by the decline of those species that are

restricted to, or highly dependent on, farmland habitats (the ‘specialists’). Between 1970

and 2019, the farmland specialists index declined by 73%; farmland generalists declined,

also by 6%. The smoothed trend shows a significant decline of 74% for specialists and a

(non-significant) 10% decline for generalists (figure 2a).

Figure 2a: Breeding farmland birds in England, 1970 to 2019

http://sciencesearch.defra.gov.uk/Default.aspx?Menu=Menu&Module=More&Location=None&ProjectID=19528

Notes:


ii) graph shows unsmoothed trends (dashed lines) and smoothed trends (solid lines).

Farmland specialists

Changes in farming practices, such as the loss of mixed farming systems, the move from

spring to autumn sowing of arable crops, and increased pesticide use, have been

demonstrated to have had adverse impacts on farmland birds such as skylark and grey

partridge. Five farmland specialists (turtle dove, tree sparrow, grey partridge, corn

bunting and starling) have declined by in excess of 80% relative to 1970 levels. By

contrast, 2 other farmland specialists (stock dove and goldfinch) have more than doubled

over the same period, illustrating how responses to pressures varies between species.

Figure 2b: Breeding specialist farmland birds in England, 1970 to 2019

Notes:




Long term

Overall, 17% of the 12 specialist species in the farmland indicator increased, 8% showed

little change and 75% declined over this long-term period. The indices for turtle dove, tree

sparrow, grey partridge, corn bunting and starling all show strong declines of 98%, 96%,

93%, 89% and 88% respectively since 1970. Specialist farmland species which increased

were goldfinch, by 174%, and stock dove, by 112%, over this long-term period.

Short term

The smoothed index shows that between 2013 and 2018 specialist farmland species

declined significantly by 6% on average. Over this period 42% of the 12 specialist species

showed a declining trend. In particular, turtle dove, grey partridge and whitethroat showed

strong declines in the short term, with turtle dove decreasing even faster, by 42%.

Yellowhammer showed a weak decline over both the long and short term. Between 2013

and 2018, 17% of specialist species increased, with goldfinch and stock dove both

increasing by 19% and 21% respectively over this short-term period.

Farmland generalists

There are 7 generalist farmland species included in the indicator and they utilise a wider

range of habitats than the specialist farmland species. Since 1970 the generalist farmland

smoothed index has fallen, not significantly, by 10%.

Figure 2c: Breeding generalist farmland birds in England, 1970 to 2019

Notes:




Long term

Since 1970, generalist farmland species have fared better than specialists over the long

term; 29% of the 7 generalist species in the indicator increased, 43% showed little change

and 29% declined. The indices for woodpigeon and jackdaw populations have more than

doubled relative to 1970 levels, while numbers of yellow wagtail and greenfinch have

declined by 65% and 62% respectively.

Short term

The smoothed index shows that between 2013 and 2018 generalist farmland species

declined significantly by 7% on average. Only one of the seven species declined over this

period; greenfinch showing a strong decline of 46% whereas its long-term trend is a weak

decline. Greenfinch numbers have been negatively impacted by the disease

trichomonosis, which may also have affected the turtle dove, a farmland specialist, in

recent years. Jackdaw is the only species to have increased, by 10%, over this period.

3. Breeding woodland bird populations in England

Woodland trees and the understorey provide nesting for birds as well as foraging

opportunities and cover from predators.

In 2019 the breeding woodland bird indicator for England was 27% lower than in 1970.

The greatest decline occurred between the early 1980s and the early 1990s, since 1996

the index has been relatively stable although more recently the smoothed index decreased

significantly by 6% between 2013 and 2018.

Figure 3: Breeding woodland birds in England, 1970 to 2019

Notes:




Long term

Since 1970, 24% of woodland species increased in number, 44% showed little change and

32% declined, the majority of the latter show a strong decline.

Short term


showed little change and 41% declined. Three species showed a strong decline in the long

term and a strong decline in the short term. These are lesser redpoll, tree pipit and spotted

flycatcher; decreasing by 31%, 21% and 18% respectively between 2013 and 2018.

Numbers of chaffinch and redstart showed a long-term trend of little change, but a strong

decline in the short term.

Factors affecting woodland birds

The declines in woodland birds have several known and potential causes, such as a lack

of woodland management including the cessation of traditional practices such as

coppicing, and increased deer browsing pressure, both of which result in a reduced

diversity of woodland structure and, therefore, reduced availability of suitable nesting and

foraging habitats. Changes in farmland management, such as the removal of hedgerows,

adversely impacted many of the species in the indicator which have substantial

populations outside of woodland e.g. in farmland and gardens. In addition, several

declining woodland birds are long-distance migrants, and a decline in the extent or quality

of habitats used outside of the UK in the non-breeding season may be one factor affecting

these species. Positive factors include the increasing area of woodland cover and milder

winters potentially having a beneficial impact for some species.


‘Annex 1.04 Evidence Statement for C5b Woodland Birds’.

Species breakdown

The woodland bird index is comprised of trends for 34 species. The relatively stable trend

for all woodland birds from the late 1990s masks different underlying trends for specialist

species, which are highly dependent on woodland habitats; and generalist species, which

are found in a wide range of habitats, including woodland.

The long-term decline of the woodland bird indicator in England has been mostly driven by

the decline of specialist woodland birds. Between 1970 and 2019, the index for woodland

specialists declined by 41% while the index for woodland generalists increased by 7%.

The smoothed trend (between 1970 and 2018) shows a significant decline of 40% for

specialists and zero change for woodland generalists (figure 3a).

Figure 3a: Breeding woodland birds in England, 1970 to 2019

Notes:



ii) graph shows unsmoothed trends (dashed lines) and smoothed trends (solid lines).

Woodland specialists

For 9 species of the woodland specialists their numbers have more than halved since

1970, with 4 species (lesser redpoll, willow tit, spotted flycatcher and tree pipit) having

declined by 90% or more. By contrast, populations of 6 woodland specialists (blackcap,

chiffchaff, great spotted woodpecker, green woodpecker, nuthatch and sparrowhawk) have

more than doubled since 1970. However, the great spotted woodpecker showed little

change in the short term and numbers for both the green woodpecker and sparrowhawk

showed strong declines since 2013.

The smoothed index for specialists shows a significant 10% decline between 2013 and

2018. However, species within it show markedly different trends over this 5-year period.

Lesser redpoll and wood warbler have decreased by over 30%, whereas nuthatch and

blackcap show increases of 17% and 14% respectively between 2013 and 2018.

Figure 3b: Breeding specialist woodland birds in England, 1970 to 2019

Notes:




Long term

Overall, 32% of the 22 specialist species in the woodland indicator increased, 27%

showed little change and 41% declined over the long-term period.

Short term

In the short term, 18% of all specialist woodland species increased, 23% showed little

change and 59% declined, with half of these species showing a strong decline.

Woodland generalists

The majority of generalist woodland species, many of which have adapted to using gardens

and wooded areas in farmland, have not shown any change over the long term.

Figure 3c: Breeding generalist woodland birds in England, 1970 to 2019

Notes:




Long term

The majority of generalist species showed little change, whilst song thrush and bullfinch

showed weak declines of 51% and 42% respectively. In contrast, populations of great tit,

long-tailed tit, robin and wren have increased by more than 50% since 1970.

Short term

The smoothed index shows a non-significant 2% increase between 2013 and 2018 for

generalist woodland species. One of the 12 species decreased over this short-term period;

chaffinch by 28%. Wren and lesser whitethroat increased by 18% and 15% respectively in

the short term.

4. Breeding water and wetland bird populations in England

Water and wetlands6 include rivers, lakes, ponds, reedbeds, grazing marshes, other wet

grasslands, and lowland raised bogs, all providing important habitats for birds [Footnote 6:

Species included in the wetland indicator are those defined as having a positive association with waterways

or wetlands, but in practice, these overlap markedly with those classified as ‘lowland wetland’ species and

also include some upland birds and those also associated with farmland, for example reed bunting and

yellow wagtail].

Produced largely using the population trends from surveys in wetland habitats, the water

and wetland bird index has remained fairly stable for most of the period since data

collection started in 1975. In 2019 the water and wetland bird index was 1% higher than

the 1975 baseline. Numbers rose slightly in the early 2000s then fell; the smoothed index

showed a non-significant 1% increase between 2013 and 2018.

Figure 4: Breeding water and wetland birds in England, 1975 to 2019

Notes:




6 Species included in the wetland indicator are those defined as having a positive association with waterways

or wetlands, but in practice, these overlap markedly with those classified as ‘lowland wetland’ species and also

include some upland birds and those also associated with farmland, for example reed bunting and yellow

wagtail.

Long term

Of the 25 species for which a long-term trend can be calculated, 28% of species

increased, 48% showed little change and 24% declined, with the majority of species

exhibiting a change show a weak rather than a strong change. For little egret, data can

only be included from 2004 and therefore a long-term trend could not be calculated (for

more information on the time series used for different species long-term trends, see Annex

A).

Short term



Factors affecting water and wetland bird populations

The historical declines in breeding waders resulted from land management changes such

as drainage, the intensification of grassland management and the conversion of coastal

and floodplain grazing marshes to arable land. Where populations persist in small

fragments of high-quality habitat, their nests and young can be vulnerable to predation,

which is currently thought to be limiting the recovery of several species of breeding wader.

However, a range of species, particularly those associated with standing water bodies,

have benefitted from habitat creation, particularly from the restoration of post-extraction

gravel pits. Additionally, there has been a net positive impact from improved survival rates

due to the trend towards milder winters.


‘Annex 1.05 Evidence Statement for C5c Wetland Birds’.

Species breakdown

The 26 species of bird included in the water and wetland bird index can be split into 4

categories for producing sub-habitat indicators. Although the index for all wetland and

waterways species shows a relatively stable trend, this masks underlying and marked

differences between sub-habitat indicators (figure 4a). When interpreting these trends, it

should be borne in mind that each sub-habitat trend is derived from relatively few species’

trends.


Figure 4a: Breeding water and wetland birds in England, 1975 to 2019

Notes:


ii) graph shows unsmoothed trends (dashed lines) and smoothed trends (solid lines),

iii) the number of species in each of the sub indicators do not sum to the all species indicator because 4

species in the main breeding wetland and waterways indicator are not included in any of the sub-indicators

covering birds of reed beds, fast flowing waterways, standing and slow-flowing waterways, or wet

grasslands. These are sand martin, kingfisher, grey heron and oystercatcher. None of these species show a

strong preference for any one of those habitats, either being fairly generalist or with large proportions of their

populations in other habitats such as coasts (e.g. oystercatcher).

Birds of slow flowing and standing water

Birds of slow flowing and standing water show the most positive trend, potentially

benefitting most from wetland creation, with the index increasing by 43% since 1975

(Figure 4b). However, the smoothed indicator shows a significant 9% decline between

2013 and 2018. The long-term increase was driven by 2 duck species, (mallard and tufted

duck), each doubling in numbers. Great crested grebe showed a weak decline. Numbers

for moorhen and little grebe show little change since 1975.

Figure 4b: Breeding slow flowing and standing waterbirds in England, 1975 to 2019

Notes:




Long term

Overall, 2 of the 6 species showed a weak increase in the long term, 3 showed little

change and one showed a weak decrease.

Short term

In the short term one species increased, one showed little change and 4 species declined

(the majority showed a strong decline). Numbers of little grebe showed a 7% increase

between 2013 and 2018. Numbers of tufted duck, coot and great crested grebe all

declined strongly by 19%, 15% and 13% respectively in the short term.

Birds of fast flowing water

The index for birds of fast flowing water was 17% lower in 2019 than in 1975. Numbers

dipped during 2009 to 2014, although not as low as in the early 1980s. The index has

recovered in the most recent years and between 2013 and 2018 it increased, not

significantly by 3% (Figure 4c).

Figure 4c: Breeding birds of fast flowing water in England, 1975 to 2019

Notes:




Long term

Numbers of goosander have increased by 86% since 1981 (when data for this species

began). However, numbers of dipper, grey wagtail and common sandpiper show little

change compared to their 1975 baseline levels.

Short term

One of the four species increased in the short term (2013 to 2018); grey wagtail increased

by 23%. Both common sandpiper and goosander show little change since 2013. Numbers

of dipper showed a 6% decrease in the short term.

Birds of reedbeds

The index for birds of reedbeds has fluctuated over the long-term period, and in 2019 was

1% lower than in 1975 (Figure 4d). The smoothed index peaked in 2009 and showed a 1%

decrease over the short term between 2013 and 2018.

Figure 4d: Breeding birds of reedbeds in England, 1975 to 2019

Notes:




Long term

In the long term, reed bunting and sedge warbler showed declines of 56% and 48%

respectively, contrasting with a 7-fold increase in Cetti’s warbler since 1988 (when the

species exceeded the 300 pair threshold for inclusion in the indicator, following the

colonisation of the UK in 1972), and reed warbler showed little change.

Short term

Over the short-term, numbers of sedge warbler have declined strongly, falling by 15%

between 2013 and 2018. Reed bunting numbers have also fallen by 13% in the short term.

Cetti’s warbler has continued to increase strongly, by 30% between 2013 and 2018, and

reed warbler has shown little change.

Birds of wet grassland

The index of birds of wet grassland decreased by 31% compared to 1975 (Figure 4e).

The majority of the decline occurred between the mid-1980s and the mid-1990s. More

recently the indicator has levelled off; the smoothed indicator shows a non-significant

10% increase between 2013 and 2018.

Figure 4e: Breeding birds of wet grassland in England, 1975 to 2019

Notes:




Long term

Over the long term, although some wet grassland species (mute swan and teal) increased,

3 species declined, and 2 species showed little changed. Of the 3 species which declined,

one species, the yellow wagtail, has declined strongly by 97% in riverine habitats

compared to their 1975 baseline. Snipe and redshank have also decreased, by 67% and

58% respectively, since 1975.

Short term

Over the short term, both yellow wagtail and redshank show strong declines of 20% and

14% respectively between 2013 and 2018. Snipe trends have reversed, showing a strong

short-term increase of 42% in contrast to its long-term decline. Lapwing numbers show

little change, both in the long and short term. Little egret, which was included for the first

time in 2006 (when the population first exceeded the 300 pair lower threshold for inclusion)

and therefore not assessed over the long term, showed a strong increase of 54% since

2013.

5. Breeding seabird populations in England

The breeding seabird index has now been updated with data up to and including 2019.

In addition to the annual monitoring scheme (Seabird Monitoring Programme; SMP),

JNCC is working, in association with other SMP partners, on the completion of the

next breeding seabird census, Seabirds Count (2015-2021) across Britain and

Ireland. Regular counts at a sample of colonies provide robust trends, but entire

population censuses are also required to add context and help to identify why

changes might be happening, as well as to enable the calculation of between-census

trends for those seabird species not monitored by the annual sample surveying.

Additionally, conducting periodic censuses allows the accuracy of SMP annual

monitoring trends to be tested and the opportunity to understand how breeding

seabird populations might be changing spatially. This is especially important when

considering inland and urban breeding species, which are rarely monitored annually.

The seabird figures are based on very recently updated data and are presented with

unsmoothed confidence intervals. Smoothed trends and assessments of change

based on smoothed trends will be calculated subsequently.

The English coast consists of a wide variety of habitats such as sea cliffs, sand dunes,

shingle ridges and intertidal areas. The marine habitats used for foraging by this group of

birds include coastal lagoons and shallow coastal waters as well as deeper offshore

waters throughout the UK. Although inland populations are largely excluded, some species

will also exploit terrestrial food sources.

In 2019, the breeding seabird index in England was 11% higher than in 1986. The

indicator has increased to the current level between 1986 and about 1992 since when it’s

been stable with fluctuations. In the short term, the index increased by 4% between 2013

and 2018.

Figure 5: Breeding seabirds in England, 1986 to 2019

Notes:

i) figures in brackets show the number of species.

ii) graph shows unsmoothed trend (dashed line) with its 95% confidence interval (shaded area) - no

smoothed trend is available for seabirds, but this will be available in future publications.

https://jncc.gov.uk/our-work/seabird-monitoring-programme/

https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fjncc.gov.uk%2Four-work%2Fsmp-report-1986-2018%2F&data=04%7C01%7CKaren.Thomas%40defra.gov.uk%7C4b8f3b6259944811e86908d88599141a%7C770a245002274c6290c74e38537f1102%7C1%7C0%7C637406239812795910%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=KmZ61QaLAmr6Bxhewe7SCdDW4hrdQg0tI7QKa7HQck8%3D&reserved=0

Long term

Between 1986 and 2018, 18% of the 11 seabird species increased, 45% showed little

change and 36% declined, the majority of the latter show a weak decline.

Short term

Over the short-term period between 2013 and 2018, 55% of the species increased, 9%


Figure 5a: Breeding surface and subsurface feeding seabirds in England, 1986 to

2019

Notes:


ii) graph shows unsmoothed trend (dashed line) - no smoothed trend is available for seabirds, but this will be

available in future publications.

Species breakdown

Long term

There are 11 species of bird included in the England seabird indicator. This includes

gannet, which has shown a rapidly increasing trend at the only English colony at

Bempton Cliffs, Yorkshire, which has had a marked positive effect on the indicator. A

breakdown by feeding behaviour (Figure 5a) shows a 22% decline in seabirds that

forage on the surface of the sea (surface piscivores) in contrast with a 168% increase

in those that forage by diving (subsurface piscivores). Numbers of herring gull, the

European shag, little tern and black-legged kittiwake have all declined by 75%, 53%,

44% and 41% respectively in the long term. In contrast, numbers of common guillemot

and gannet show a strong increase; common guillemot numbers have more than

doubled and gannet numbers increased 20-fold between 1986 and 2018.

Short term

Over the short term between 2013 and 2018, sandwich tern, Arctic tern, common tern

and gannet all show strong increases between 2013 and 2018. Numbers of little tern,

European shag, and herring gull continue to decline strongly, falling more than 15%

between 2013 and 2018.

This measure is focussed on the marine environment. Accordingly, for a number of

species (e.g. herring gull, great cormorant), the indicator uses data for coastal

populations (colonies within 5km of the coastline) only rather than data from all

breeding areas of these species. This focusses the indicator on changes at the coast

and in marine waters but means changes in inland populations are not taken into

account. Work is currently underway to improve survey coverage of inland colonies so

that a trend based on all breeding areas can be included in the ‘all species indicator’.

The seabird index in England continues to show a different pattern to the UK seabird

index7 [Footnote 7: The UK seabird trend can be seen in the Defra National Statistics Release, Wild bird

populations in the UK, 1970 to 2019, also published today]. One reason for this difference is species

composition. Some species breed only in Scotland whereas others are more widespread

but have the bulk of their populations in northern parts of the British Isles, and there may

be insufficient data to generate an England-only trend. Furthermore, it was also possible to

generate an England trend for gannet based on reliable data from a single large colony, but

there are insufficient data representative of the UK population to produce a reliable UK trend

for this species.


‘Annex 1.06 Evidence Statement for C5d Seabirds’.

7 The UK seabird trend can be seen in the Defra National Statistics Release, Wild bird populations in the UK,

1970 to 2019, also published today.


6. Wintering waterbird populations in England

The term waterbird refers to birds that inhabit or depend on water and wetland habitats;

this chapter is about waterbirds that over-winter in England, some of which also breed in

England8 [Footnote 8: Not all of the wintering waterbirds in this chapter are included in the all breeding

birds index, only those which also breed in England and for which breeding trends are available. In Annex A

those species that overlap are included under both].

In the winter of 2018/19, the wintering waterbird index was 76% higher than in 1975/76.

The index peaked in the late 1990s, and has declined since, with the smoothed index

falling 6% in the short term between 2012/13 and 2017/18.

Figure 6: Wintering waterbirds in England, 1975/76 to 2018/19

Notes:


ii) graph shows unsmoothed trend (dashed line) and smoothed trend (solid line). Data from surveys

of wintering waterbirds are based largely on full counts at colonies or wetland and coastal sites of markedly

varying size. This means that bootstrapping methods cannot be applied reliably and hence trends for these

groups are currently presented without confidence intervals.

iii) the number of species in each sub indicator do not sum to the number in the all-species indicator because

4 species are included in all wintering waterbirds but are neither wildfowl nor wader. These are 2 grebes

(little and great-crested), one rail species (coot) and cormorant. These are in 3 different taxonomic groups

none large enough to warrant a separate indicator.

8 Not all of the wintering waterbirds in this chapter are included in the all breeding birds index, only those which

also breed in England and for which breeding trends are available. In Annex A those species that overlap are

included under both.

Long term

Since 1975/76, 46% of wintering waterbird species increased, 37% showed little change

and 17% declined, most of these showing a weak decline.

Short term

Over the short-term period between the winters of 2012/13 and 2017/18, 24% of species

increased, 37% showed little change and 39% declined.

Factors affecting wintering wetland bird populations

Breeding wintering wetland birds are affected by a range of factors including conditions in

the high latitude countries where they breed, with breeding productivity increasing for

species including black-tailed godwit but decreasing for others such as Greenland white-

fronted geese. There is good evidence of a strong climate change impact on the indicator

in recent years, with milder winters leading to the wintering ranges of some species, such

as ringed plovers, increasingly shifting away from the UK. In addition, local changes, such

as wetland creation and changes in agricultural management, have had an impact on

waterbird populations within the UK.


‘Annex 1.07 Evidence Statement for C5e Wintering Waterbirds’.

Species breakdown

There are 41 species, races and populations of bird included in the wintering waterbird

indicator. These can be split into subcategories of wildfowl (ducks, geese and swans) and

waders (sandpipers, plovers and their close relatives) which display slightly different

trends. Overall, the smoothed wildfowl index has increased by 90% and the wader index

has increased 51% between 1975/76 and 2017/18. However, both peaked in the late

1990s and between 2012/13 and 2017/18, both the smoothed indices for waders and

wildfowl declined by 3% and 11% respectively.


Wildfowl

Long term

Since the winter of 2017/18, half of the wildfowl species increased, 27% showed little

change and 23% declined. Notable strong increases included Whooper swan, gadwall and

British/Irish greylag goose, which increased greatly by 22, 15 and 13-fold respectively in

the long term. Numbers of scaup have declined strongly by 83% since 1975/76. There

were also long-term declines for wildfowl species: European white-fronted goose, Bewick’s

swan, pochard and eider of 61%, 56%, 55% and 48% respectively.

Short term

Between the winters of 2012/13 and 2017/18, 23% of species in the wildfowl indicator

increased, 18% showed little change and 59% declined. The majority of species in the

wildfowl indicator declined, with Bewick’s swan, red-breasted merganser and eider

declining strongly by 48%, 34% and 32% respectively over this short-term period. The

indices for both shoveler and pink-footed goose increased strongly by 22% and 16%

respectively between the winters of 2012/13 and 2017/18.

Waders

Long term

Since the winter of 2017/18, 33% of species in the wader index increased, 53% showed

little change and 13% declined The indices for both avocet and black-tailed godwit

increased strongly by 8 and 7-fold respectively in the long term In contrast, numbers of

ringed plover and dunlin decreased by 52% and 50% respectively since 1975/76.

Short term

Between the winters of 2012/13 and 2017/18, 13% of wader species increased, 73%

showed little change and 13% declined. Both indices for curlew and bar-tailed godwit

showed strong declines of 21% and 17% respectively. The indices for sanderling and

black-tailed godwit increased weakly by 13% and 6% respectively.

Main notes: methodological detail, limitations of the indicators and further information

1. The bird population indices have been compiled in conjunction with the British Trust for

Ornithology (BTO), the Joint Nature Conservation Committee (JNCC), the Wildfowl and

Wetlands Trust (WWT), and the Royal Society for the Protection of Birds (RSPB) from

a wide range of sources, principally:

• the Common Birds Census (from 1966 to 2000),

• the BTO/JNCC/RSPB Breeding Bird Survey (from 1994 to 2019),

• the BTO/ Waterways Bird Survey (from 1974 to 2007),

• the BTO/JNCC/RSPB Waterways Breeding Bird Survey, with support from the

Environment Agency (from 1998 to 2019),

• the BTO/RSPB/JNCC Wetland Bird Survey counts (from 1975/76 to 2018/19),

• the WWT Goose & Swan Monitoring Programme in partnership with the JNCC

and Scottish Natural Heritage,

• the Seabird Monitoring Programme (from 1986 to 2019),

• the Periodic Seabird censuses supplied by JNCC, RSPB, the Seabird Group,

SOTEAG (Shetland Oil Terminal Environmental Advisory Group) and other

partners,

• Monitoring of scarce and rare breeding birds by the Statutory Conservation

Agency and RSPB Annual Breeding Bird Scheme (SCARABBS) and the Rare

Breeding Birds Panel (from 1970 to 2018).

The census sources provide an indication of the average annual rate of change

between censuses for some species, and this is assumed to apply to each year

between censuses.

More information about individual species trends, including photographs, and

background to the changes in population are available via the BTO website. Some

regional analysis is also published as part of the Breeding Bird Survey, including for

other constituent countries of the UK. More information about the State of UK birds

can be accessed through the RSPB website. Details on the monitoring of scarce

and rare breeding birds, including annual reports, can be found on the website of

the Rare Breeding Birds Panel.

2. The indices cover birds that are native to the England, excluding rare (less than 300

breeding pairs) and introduced species. The indices portray the annual changes in

abundance. Within the indices, each species is given equal weighting, and the overall

index is the geometric mean of the individual species indices. Individual species

populations within the index may be increasing or decreasing, irrespective of the

overall index trends. Species indices are derived by modelling count data and

estimates are revised when new data or improved methodologies are developed and

applied retrospectively to earlier years.

http://www.bto.org/survey/complete/cbc.htm

http://www.bto.org/volunteer-surveys/bbs

http://www.bto.org/volunteer-surveys/wbbs



http://www.bto.org/volunteer-surveys/webs

http://monitoring.wwt.org.uk/surveys.php

http://jncc.defra.gov.uk/page-1550

http://www.rbbp.org.uk/


http://www.bto.org/birdtrends2010/species.htm

http://www.bto.org/volunteer-surveys/bbs/latest-results/trend-graphs

http://www.rspb.org.uk/forprofessionals/science/sotukb/


3. The indices are considered to give reliable medium to long-term trends but strong

reliance should not be attached to short-term changes from year to year.

4. The individual species included within each indicator are given in Annex A.

5. Smoothing is a standard procedure in the generation and reporting of bird population

trends (www.bto.org/birdtrends2010/methodology.htm). The smoothing methodology

involves the application of a thin plate smoothing spline to remove the short-term peaks

and troughs due to weather effects and any between year sampling error. Research by

the BTO and RSPB further developed this procedure to enable the production of an

indicator based on smoothed individual species’ indices.

6. Bootstrapping, a standard statistical technique, is used to calculate 95% confidence

intervals in the indicators and in change over any specified period. The width of the

confidence interval for a given indicator is influenced by the number of species in that

indicator and the precision of the individual species trends that make up that indicator.

The precision of trends varies between species; this is true even for species for which

trends come from the same source, due to the variation in sample size. Therefore, the

size of confidence intervals varies among habitat indicators.

7. For the farmland bird index, it should be noted that although 20 species were originally

chosen for the index, a reliable annual index is not available for barn owl, so that

species is excluded.

8. Details of agri-environmental schemes designed to improve environmental

management in farming can be found via the following administrating bodies:

• Natural England

9. Defra previously also published an annual National Statistics Release, Wild bird

population indicators for the English regions. This Release was discontinued in 2011,

as a result of resource constraints and changes in regional governance. The last

release9 covered trends for 1994 to 2008 and was published in 2010 [Footnote 9:

www.defra.gov.uk/statistics/files/wdbrds2010004.pdf]. However, these statistical releases drew

upon results from the Joint BTO/JNCC/RSPB Breeding Bird Survey and some regional

analysis will continue to be published as part of the Breeding Bird Survey, including for

the other constituent countries of the UK.

9 www.defra.gov.uk/statistics/files/wdbrds2010004.pdf


http://www.naturalengland.org.uk/ourwork/farming/funding/es/default.aspx

http://www.bto.org/volunteer-surveys/bbs/latest-results/trend-graphs

36

Annex A: Trends in bird species, by habitat10 group, in England

[Footnote 10: Habitat classifications are generally based on ‘Gibbons, D.W., Reid, J.B. & Chapman, R. A. 1993. The New Atlas of Breeding Birds in Britain and Ireland:

1988 to 1991. London: T. & A.D. Poyser]

The tables below list the species that are included in each indicator. Percentage changes are based on smoothed data, except in the

case of seabirds, for which no smoothed trend data are available. Annual percentage change represents the rate of change over the time

period shown, allowing the assessment of strong or weak to be made. ‘Strong’, ‘weak’, ‘little change’ is determined by how much the

population would change if the average rate of annual change (over the specified period, long or short term) continued for 25 years.

Farmland (19)

Generalists (7) Long-term change (1970-2018) Short-term change (2013-2018)

Species Long-term percentage

change

Annual percentage

change

Trend Short-term percentage

change

Annual percentage

change

Trend

Greenfinch (Chloris chloris) -62 -2 weak decline -46 -11.5 strong decline

Jackdaw (Corvus monedula) 155 1.97 weak increase 10 1.9 weak increase

Kestrel (Falco tinnunculus) -31 -0.76 little change 1 0.16 little change

10 Habitat classifications are generally based on ‘Gibbons, D.W., Reid, J.B. & Chapman, R. A. 1993. The New Atlas of Breeding Birds in Britain and Ireland: 1988 to

1991. London: T. & A.D. Poyser.

37

Reed Bunting (Emberiza schoeniclus)

-29 -0.71 little change 4 0.72 little change

Rook (Corvus frugilegus) 16 0.35 little change 0 -0.03 little change

Woodpigeon (Columba palumbus) 133 1.78 weak increase -3 -0.53 little change

Yellow wagtail (Motacilla flava) -65 -2.19 weak decline -1 -0.16 little change

Specialists (12) Long-term change (1970-2018) Short-term change (2013-2018)


change

Annual percentage

change


change

Annual percentage

change

Trend

Corn bunting (Emberiza calandra) -89 -4.44 strong decline 5 0.94 little change

Goldfinch (Carduelis carduelis) 174 2.12 weak increase 19 3.6 strong increase

Grey partridge (Perdix perdix) -93 -5.31 strong decline -19 -4.18 strong decline

Lapwing (Vanellus vanellus) -53 -1.55 weak decline -4 -0.72 little change

Linnet (Carduelis cannabina) -63 -2.06 weak decline 2 0.43 little change

Skylark (Alauda arvensis) -61 -1.96 weak decline -1 -0.26 little change

Starling (Sturnus vulgaris) -88 -4.26 strong decline -2 -0.32 little change

Stock dove (Columba oenas) 112 1.58 weak increase 21 3.87 strong increase

Tree sparrow (Passer montanus) -96 -6.31 strong decline -9 -1.81 weak decline

Turtle dove (Streptopelia turtur) -98 -7.94 strong decline -42 -10.38 strong decline

Whitethroat (Sylvia communis) -16 -0.37 little change -14 -2.91 strong decline

Yellowhammer (Emberiza citrinella) -66 -2.2 weak decline -11 -2.37 weak decline

38

Woodland (34)

Generalists (12) Long-term change (1970-2018) Short-term change (2013-2018)


change

Annual percentage

change


change

Annual percentage

change

Trend

Blackbird (Turdus merula) -18 -0.4 little change 2 0.37 little change

Blue tit (Cyanistes caeruleus) 19 0.36 little change -2 -0.39 little change

Bullfinch (Pyrrhula pyrrhula) -42 -1.14 weak decline 3 0.67 little change

Chaffinch (Fringilla coelebs) -5 -0.11 little change -28 -6.31 strong decline

Dunnock (Prunella modularis) -36 -0.92 little change -2 -0.37 little change

Great tit (Parus major) 73 1.15 weak increase 2 0.39 little change

Lesser whitethroat (Sylvia curruca) 22 0.41 little change 15 2.9 strong increase

Long-tailed tit (Aegithalos caudatus)

71 1.12 little change 5 0.95 little change

Robin (Erithacus rubecula) 64 1.04 little change 8 1.53 weak increase

Song thrush (Turdus philomelos) -51 -1.5 weak decline 10 1.91 weak increase

Tawny owl (Strix aluco) -36 -0.93 little change 1 0.15 little change

Wren (Troglodytes troglodytes) 60 0.99 little change 18 3.29 strong increase

39

Specialists (22) Long-term change (1970-2018) Short-term change (2013-2018)


change

Annual percentage

change


change

Annual percentage

change

Trend

Blackcap (Sylvia atricapilla) 292 2.89 strong increase 14 2.7 weak increase

Chiffchaff (Phylloscopus collybita) 102 1.48 weak increase 3 0.65 little change

Coal tit (Periparus ater) 38 0.67 little change 9 1.75 weak increase

Garden warbler (Sylvia borin) -17 -0.39 little change 0 -0.06 little change

Goldcrest (Regulus regulus) -18 -0.42 little change 8 1.47 weak increase

Great spotted woodpecker (Dendrocopos major)

307 2.97 strong increase -4 -0.89 little change

Green woodpecker (Picus viridis) 103 1.49 weak increase -15 -3.24 strong decline

Jay (Garrulus glandarius) -4 -0.09 little change -10 -2.13 weak decline

Lesser spotted woodpecker (Dendrocopos minor)

-70 -2.47 weak decline -8 -1.56 weak decline

Marsh tit (Poecile palustris) -73 -2.66 weak decline -5 -1.12 little change

Nightingale (Luscinia megarhynchos)a

-55 -3.45 strong decline -27 -6.19 strong decline

Nuthatch (Sitta europaea) 307 2.97 strong increase 17 3.27 strong increase

Lesser redpoll (Carduelis cabaret) -95 -6.21 strong decline -31 -7.16 strong decline

Redstart (Phoenicurus phoenicurus)

28 0.51 little change -17 -3.55 strong decline

Sparrowhawk (Accipiter nisus) 114 1.6 weak increase -21 -4.64 strong decline

Spotted flycatcher (Muscicapa striata)


Wood warbler (Phylloscopus sibilatrix)a


Siskin (Carduelis spinus)a 56 1.96 weak increase -10 -2.08 weak decline

Tree pipit (Anthus trivialis) -90 -4.62 strong decline -21 -4.53 strong decline

40

Treecreeper (Certhia familiaris) -14 -0.32 little change 3 0.5 little change

Willow tit (Poecile montana) -94 -5.73 strong decline -12 -2.63 weak decline

Willow warbler (Phylloscopus trochilus)


a Data for the long-term assessment are from 1995 to 2018

41

Water and wetland birds (26)

Birds of fast flowing water (4) Long-term change (1975-2018) Short-term change (2013-2018)


change

Annual percentage

change


change

Annual percentage

change

Trend

Common sandpiper (Actitis hypoleucos)

-35 -0.99 little change 0 -0.07 little change

Dipper (Cinclus cinclus) -19 -0.5 little change -6 -1.25 weak decline

Goosander (Mergus merganser)b 86 1.69 weak increase -1 -0.19 little change

Grey wagtail (Motacilla cinerea) -34 -0.95 little change 23 4.28 strong increase

b Data for the long-term assessment are from 1981 to 2018

Birds of reedbeds (4)

Long-term change (1975-2018) Short-term change (2013-2018)


change

Annual percentage

change


change

Annual percentage

change

Trend

Cetti's warbler (Cettia cetti)c 636 7.12 strong increase 30 5.37 strong increase

Reed bunting (Emberiza schoeniclus)


Reed warbler (Acrocephalus scirpaceus)d

41 0.93 little change 0 0 little change

Sedge warbler (Acrocephalus schoenobaenus)

-48 -1.53 weak decline -15 -3.24 strong decline

c Data for the long-term assessment are from 1989 to 2018 d Data for the long-term assessment are from 1981 to 2018

42

Birds of slow and standing water (6)



change

Annual percentage

change


change

Annual percentage

change

Trend

Coot (Fulica atra) 57 1.06 little change -15 -3.13 strong decline

Great crested grebe (Podiceps cristatus)e


Little grebe (Tachybaptus ruficollis) -9 -0.22 little change 7 1.28 weak increase

Mallard (Anas platyrhynchos) 153 2.18 weak increase -10 -2.18 weak decline

Moorhen (Gallinula chloropus) -23 -0.59 little change -3 -0.53 little change

Tufted duck (Aythya fuligula) 87 1.47 weak increase -19 -4.06 strong decline

e Data for the long-term assessment are from 1995 to 2018

Birds of wet grassland (8)



change

Annual percentage

change


change

Annual percentage

change

Trend

Curlew (Numenius arquata)f -15 -0.43 little change 1 0.21 little change

Lapwing (Vanellus vanellus)f 0 -0.01 little change -4 -0.77 little change

Little egret (Egretta garzetta) N/A N/A N/A 54 9.02 strong increase

Mute swan (Cygnus olor) 118 1.83 weak increase 4 0.74 little change

Redshank (Tringa totanus) -58 -1.97 weak decline -14 -2.86 strong decline

Snipe (Gallinago gallinago) -67 -2.55 weak decline 42 7.21 strong increase

Teal (Anas crecca)g 237 5.43 strong increase 45 7.76 strong increase

Yellow wagtail (Motacilla flava) -97 -7.67 strong decline -20 -4.39 strong decline

43

f Data for the long-term assessment are from 1980 to 2018 g Data for the long-term assessment are from 1995 to 2018

Other (4)



change

Annual percentage

change


change

Annual percentage

change

Trend

Grey heron (Ardea cinerea) -21 -0.54 little change -2 -0.46 little change

Kingfisher (Alcedo atthis) -24 -0.63 little change -6 -1.24 weak decline

Oystercatcher (Haematopus ostralegus)

167 2.31 weak increase -2 -0.44 little change

Sand martin (Riparia riparia)h 19 0.43 little change 7 1.33 weak increase

h Data for the long-term assessment are from 1978 to 2018

44

Seabird (11)


Species Long-term percentage change

Annual percentage

change


change

Annual percentage

change

Trend

Black-legged kittiwake (Rissa tridactyla)

-41 -1.64 weak decline 15 2.81 weak increase

Common guillemot (Uria aalge) 147 2.86 strong increase 1 0.25 little change

European shag (Phalacrocorax artistotelis)


Great cormorant (Phalacrocorax carbo)

16 0.47 little change 14 2.61 weak increase

Herring gull (Larus argentatus) -75 -4.19 strong decline -15 -3.25 strong decline

Northern fulmar (Fulmarus glacialis)

-27 -0.98 little change -9 -1.76 weak decline

Common tern (Sterna hirundo) 4 0.13 little change 18 3.33 strong increase

Sandwich tern (Sterna sandvicensis)

8 0.24 little change 40 7.26 strong increase

Little tern (Sternula albifrons) -44 -1.78 weak decline -18 -3.85 strong decline

Arctic tern (Sterna paradisaea) 35 0.93 little change 25 4.64 strong increase

Gannet (Morus bassanus) 1960 9.92 strong increase 16 3.02 strong increase

45

Wintering waterbirds (41)

Wildfowl (22) Long-term change (1975/76-2017/18) Short-term change (2012/13-2017/18)


change

Annual percentage

change


change

Annual percentage

change

Trend

Mute swan (Cygnus olor) 209 2.72 weak increase 1 0.26 little change

Bewick's swan (Cygnus columbianus)


Whooper swan (Cygnus cygnus) 2095 7.63 strong increase 12 2.38 weak increase

Pink-footed goose (Anser brachyrhynchus)

436 4.08 strong increase 16 3.01 strong increase

White-fronted goose, European (Anser albifrons ablbifrons)


Greylag goose, British/Irish (Anser anser anser)i

1222 6.34 strong increase 10 2 weak increase

Brent goose, Dark-bellied (Branta bernicla bernicla)

151 2.22 weak increase -8 -1.71 weak decline

Brent goose, Svalbard light-bellied (Branta bernicla hrota)

808 5.39 strong increase -22 -4.9 strong decline

Shelduck (Tadorna tadorna)j 28 0.58 little change 8 1.51 weak increase

Wigeon (Anas penelope) 165 2.35 weak increase 0 0.09 little change

Gadwall (Anas strepera) 1436 6.72 strong increase -1 -0.15 little change

Teal (Anas crecca)k 142 2.13 weak increase -8 -1.74 weak decline

Mallard (Anas platyrhynchos) -24 -0.65 little change -12 -2.6 weak decline

Pintail (Anas acuta) -29 -0.83 little change 5 1.06 little change

Shoveler (Anas clypeata) 145 2.16 weak increase 22 4.07 strong increase

Pochard (Aythya ferina) -55 -1.86 weak decline -23 -4.99 strong decline

Tufted duck (Aythya fuligula) 54 1.03 little change -10 -2.05 weak decline

Scaup (Aythya marila) -83 -4.16 strong decline -15 -3.22 strong decline

46

Eider, except shetland (Somateria mollissima)


Goldeneye (Bucephala clangula) 23 0.49 little change -22 -4.82 strong decline

Red-breasted merganser (Mergus serrator)

35 0.72 little change -34 -8.02 strong decline

Goosander (Mergus merganser) 112 1.8 weak increase -11 -2.32 weak decline I Data for the long-term assessment are from 1982/83 to 2017/18 J Data for the long-term assessment are from 1988/89 to 2017/18 k Data for the long-term assessment are from 1987/88 to 2017/18

Wader (15) Long-term change (1975/76-2017/18) Short-term change (2012/13-2017/18)


change

Annual percentage

change


change

Annual percentage

change

Trend

Oystercatcher (Haematopus ostralegus)

-16 -0.42 little change -1 -0.19 little change

Avocet (Recurvirostra avosetta)l 738 7.89 strong increase 4 0.75 little change

Ringed plover (Charadrius hiaticula) -52 -1.73 weak decline 4 0.73 little change

Golden plover (Pluvialis apricaria) 200 2.65 weak increase 5 1.03 little change

Grey plover (Pluvialis squatarola) 150 2.2 weak increase -5 -1.09 little change

Lapwing (Vanellus vanellus) 114 1.83 weak increase 3 0.53 little change

Knot (Calidris canutus) 9 0.21 little change -5 -0.99 little change

Sanderling (Calidris alba) 42 0.85 little change 13 2.45 weak increase

Purple sandpiper (Calidris maritima) 11 0.26 little change -5 -1.05 little change

Dunlin (Calidris alpina) -50 -1.63 weak decline -4 -0.87 little change

Black-tailed godwit (Limosa limosa) 646 4.9 strong increase 6 1.21 weak increase

Bar-tailed godwit (Limosa lapponica)

-7 -0.18 little change -17 -3.61 strong decline

47

Curlew (Numenius arquata) -14 -0.36 little change -21 -4.6 strong decline

Redshank (Tringa totanus) 2 0.05 little change -5 -0.96 little change

Turnstone (Arenaria interpres) -11 -0.27 little change -5 -0.99 little change

l Data for the long-term assessment are from 1988/89 to 2017/18

Other (4) Long-term change (1975/76-2017/18) Short-term change (2012/13-2017/18)


change

Annual percentage

change


change

Annual percentage

change

Trend

Coot (Fulica atra)m 3 0.09 little change -15 -3.29 strong decline

Cormorant (Phalacrocorax carbo)n 129 2.89 strong increase 26 4.77 strong increase

Great crested grebe (Podiceps cristatus)m

55 1.38 weak increase 6 1.26 weak increase

Little grebe (Tachybaptus ruficollis)o 117 2.8 weak increase 11 2.04 weak increase

m Data for the long-term assessment are from 1984/85 to 2017/18 n Data for the long-term assessment are from 1987/88 to 2017/18 o Data for the long-term assessment are from 1988/89 to 2017/18

48

Other birds included in the all-species index (31)

The all-species line is comprised of all 118 available population trends for widespread breeding species in England, from all landscape

types. It excludes rare species (with less than 300 breeding pairs) and all species for which no England trend information is available.

The species composition of all species index (118 species) includes:

• 19 farmland* species trends (i.e. those in the farmland bird index);

• 34 woodland bird species (i.e. those in the woodland bird index);

• 26 breeding wetland* species (i.e. those in the breeding birds of water and wetlands index);

• 11 seabirds, and;

• 31 other species trends, including birds of urban areas, heathlands, uplands, coasts and species with no strong habitat

preferences (generalists). Some of these birds are also included under wintering waterbirds but are included here as they also

breed in the England and are included in the all-species index.

* Note that trends for 3 species (yellow wagtail, reed bunting and lapwing) are included in 2 separate habitat-specific indicators (farmland and breeding wetland) due to their reliance

on both of these habitats. The same trends as used in the farmland bird indicator are used for these 3 species in the all-species indicator to avoid duplication.



change

Annual percentage

change


change

Annual percentage

change

Trend

Avocet (Recurvirostra avosetta)p 424 0.06 strong increase 25 0.04 strong increase

Bearded tit (Panurus biarmicus) 28 0.01 little change -6 -0.01 weak decline

Black-headed gull (Chroicocephalus ridibundus)

88 0.01 weak increase -1 0.00 little change

Buzzard (Buteo buteo) 1069 0.05 strong increase 15 0.03 strong increase

Carrion crow (Corvus corone) 110 0.02 weak increase 0 0.00 little change

Cirl bunting (Emberiza cirlus)q 97 0.04 strong increase 17 0.03 strong increase

Collared dove (Streptopelia decaocto)

819 0.05 strong increase -14 -0.03 strong decline

49

Cuckoo (Cuculus canorus) -77 -0.03 strong decline -9 -0.02 weak decline

Dartford warbler (Sylvia undata)r 157 0.02 weak increase 67 0.11 strong increase

Firecrest (Regulus ignicapilla) -100 0.00 Not available 8 0.01 weak increase

Hobby (Falco subbuteo)s -27 -0.01 weak decline -14 -0.03 strong decline

House martin (Delichon urbicum)s -40 -0.02 weak decline -13 -0.03 weak decline

House sparrow (Passer domesticus)

-74 -0.03 strong decline 1 0.00 little change

Magpie (Pica pica) 103 0.01 weak increase -1 0.00 little change

Meadow pipit (Anthus pratensis) -52 -0.02 weak decline -13 -0.03 strong decline

Mediterranean gull (Larus melanocephalus)

-100 0.00 Not available 160 0.21 strong increase

Mistle thrush (Turdus viscivorus) -63 -0.02 weak decline -1 0.00 little change

Pied/White wagtail (Motacilla alba) 20 0.00 little change 1 0.00 little change

Pochard (Aythya ferina)t 140 0.03 strong increase 20 0.04 strong increase

Quail (Coturnix coturnix)u -70 -0.04 strong decline -55 -0.15 strong decline

Raven (Corvus corax)s 42 0.02 weak increase 6 0.01 weak increase

Red grouse (Lagopus lagopus scotica)s

11 0.00 little change -5 -0.01 little change

Red kite (Milvus milvus) 516 0.16 strong increase 84 0.13 strong increase

Shelduck (Tadorna tadorna)s 23 0.01 little change 4 0.01 little change

Shoveler (Anas clypeata) -100 0.00 Not available 52 0.09 strong increase

Stone curlew (Burhinus oedicnemus)


Stonechat (Saxicola rubicola)s 117 0.03 strong increase 84 0.13 strong increase

Swallow (Hirundo rustica) -22 -0.01 little change -31 -0.07 strong decline

Swift (Apus apus)s -58 -0.04 strong decline -28 -0.06 strong decline

Whinchat (Saxicola rubetra)s -47 -0.03 strong decline -15 -0.03 strong decline

Woodlark (Lullula arborea)v 142 0.02 weak increase -11 -0.02 weak decline

50

p Data for the long-term assessment are from 1988 to 2018 q Data for the long-term assessment are from 2001 to 2018 r Data for the long-term assessment are from 1974 to 2018 s Data for the long-term assessment are from 1995 to 2018 t Data for the long-term assessment are from 1989 to 2018 u Data for the long-term assessment are from 1990 to 2018 v Data for the long-term assessment are from 1980 to 2018

51

Annex B Frequently asked questions Wild Bird Populations in England, 1970 to 2019

Why monitor bird populations?

Bird populations have long been considered to provide a good indication of the broad

state of wildlife in England. This is because they occupy a wide range of habitats and

respond to environmental pressures that also operate on other groups of wildlife. In

addition, there are considerable long-term data on trends in bird populations,

allowing for comparisons between the short term and long term. Because they are a

well-studied taxonomic group, drivers of change for birds are better understood than

for other species groups, which enables better interpretation of any observed

changes.

Which species of birds are included in the indices?

There are 4 main habitat groups representing farmland, woodland, water and

wetland and seabird habitats. Species within each habitat type are included in the

indices if they have a population of at least 300 breeding pairs and are common

birds that are native to, and breed in England; the trends included refer to breeding

populations (except for those used in the winter waterbird indicator). There is also

an all-species indicator where all of the species included in the farmland, woodland,

wetland and seabird indicators are included here, as well as species associated with

urban habitats (e.g. collared dove, house martin), with uplands (e.g. hen harrier, red

grouse), with heathlands (e.g. Dartford warbler, hobby) and species that occupy a

range of habitats (e.g. peregrine, black-headed gull).

What are 'unsmoothed' and 'smoothed' indices and why are they used?

Two trends are referred to in the text: the unsmoothed indices show year-to-year

fluctuation in populations, reflecting the observed changes in the survey results, and

smoothed trends, which are used to formally assess the statistical significance of

change over time. Smoothed trends are used for both long and short-term

assessments as they reduce the short-term peaks and troughs resulting from, for

example, year-to-year weather and sampling variations.

What is the difference between a 'long-term' and 'short-term' trend?

There are no differences between the way the trends are calculated as they both use

the smoothed indices, it is only that in most cases the long-term trend goes back to

the earliest data point, usually 1970, whereas the short-term trend looks at the most

recent 5 years, that is year 6 to year 1.

52

Why should users not place too much reliance on short-term changes from

one year to another?

Looking at the data from year to year may include weather effect and sampling

variations which would not provide reliable data as the trend is not over a longer time

frame.

Why use indices rather than absolute numbers?

It is not possible to determine changes in the actual numbers of birds for each

species in England each year, however it is possible to estimate the relative change,

from counts on sample plots surveyed as part of a range of national monitoring

schemes.

How are the individual species indices combined into a single indicator and

why is it done?

The creation of the all species wild bird indicator involves two steps: (1) the

production of annual population indices for the individual species for which there is

trend data, and (2) the amalgamation of these individual indices into a single

aggregate index.

1. Indices for individual species: These are generated by a statistical analysis of

representative sites resurveyed year after year (e.g. in the Breeding Bird Survey) or

based on annual or periodic estimates of total populations (e.g. Heronries Survey).

The population trends for each species are made comparable by expressing them as

indices relative to ‘100’ in the start year. Thus each annual index shows relative

changes in population size from the start year: a rise to 200 in the index reflects a

doubling in numbers, a decline to 50 a halving.

2. Amalgamating into a single index: The all species index is calculated as the

geometric mean1 of all the individual indices2, with no weightings - so each species

has the same relative effect on the indicator. The geometric mean is used to ensure

that a doubling in the population index of one species (e.g. 100 to 200) is balanced

by a halving (e.g. 100 to 50). The geometric mean of 200 and 50 is 100.

The composite all species indicator shows the year-to-year fluctuations in population

trends across all species that can be included, reflecting the observed changes in

the annual survey results. Alongside this is the smoothed version of the trend, which

is used to formally assess the statistical significance of change over time. The

smoothed trend is derived using a published statistical methodology and is used for

assessments as it reduces the short-term peaks and troughs resulting from, for

example, year-to-year impacts of weather and sampling variations. The index is

53

considered to give reliable medium to long-term trends but strong reliance should not

be attached to short term changes from one year to the next.

What is the 'geometric mean', how is it calculated and why is it used?

The geometric mean is an average. It is calculated by multiplying a set of index

values and taking the nth root, where n is the number of index values. More

information can be found in Introduction to the Wild Birds Population Indicator. The

geometric mean is used to ensure that a doubling in the population index of one

species (e.g. 100 to 200) is balanced by a halving (e.g. 100 to 50). It allows for each

species to have the same relative effect on the indicator.

What does 'modelling count data' mean?

For those species covered by the Common Bird Census (CBC) and Breeding Bird

Survey (BBS), all data from survey sites are used in the generation of trends,

regardless of the habitat at these sites (e.g. survey data from woodland sites is used

in the trends for farmland species and vice versa). Trends are generated from the

two data sources using the joint-model methods described by Noble et al. (2003a).

Generalized linear models (GLMs) are used, with the application of a post-hoc

smoothing spline to produce smoothed indices for each species, thereby removing

short-term fluctuations that may be caused by sampling error, or minor fluctuations

due to weather effects, for example. Such smoothing does however mean that the

estimates for the final year of a trend must be treated with caution as they lack the

smoothing effect of data in subsequent years. The nature of smoothed trends, in that

data from any given year has an impact on trend values for earlier (and later) years

means that existing species indices (and hence indicator) values will be different in

subsequent annual revisions.

Data from the CBC and BBS are combined and analysed statistically in a single GLM

with site and year effects, as described at http://www.bto.org/about-

birds/birdtrends/2013/methods/cbcbbs-trends. Equal weight is given to CBC and

BBS sites by assigning each CBC site the mean of the BBS site weighting.

Confidence limits on these species trends are generated by bootstrapping; repeated

resampling (with replacement) to generate a sample of estimated trend values, with

the 2.5% and 97.5% percentiles giving the 95% confidence limits around the trend

value for each year.

What are 'confidence intervals' and why are they used?

The trends in this publication are based on estimates from surveys. Smoothed trends

are presented with 95% confidence intervals (CI), which are a measure of the

precision of these survey estimates. While the exact value for an indicator in a


http://www.bto.org/about-birds/birdtrends/2013/methods/cbcbbs-trends

http://www.bto.org/about-birds/birdtrends/2013/methods/cbcbbs-trends

54

particular year cannot be known, a 95% CI means users can be 95% confident that

the true value of the indicator falls within the confidence interval around it.

Why are the confidence intervals for some indices such as 'breeding generalist

farmland birds' so much wider than they are for other indices such as

'breeding generalist woodland birds' and what is it indicating?

The size of confidence intervals (CIs) varies among habitat indicators because their

width is influenced by the number of species in each indicator and the precision of

the individual species trends that make up the indicator. The precision of these

trends varies due to differences in sample size. More specifically, the CIs for

generalist farmland birds indicator is wider than the CIs for generalist woodland birds

indicator because there are only 7 individual species in the former indicator, whereas

there are 12 species in the latter. Wider confidence intervals imply that the range of

values within which users can be confident the true indicator value falls is greater

than it would be for a narrower confidence interval. Therefore, users can be 95%

confident that the true value of the breeding generalist woodland birds indicator falls

within a narrower range of values than the true value of the breeding generalist

farmland birds indicator.

Why is the percentage change used to define a 'weak increase' different to that

used to define a 'weak decline'?

Asymmetric percentage change thresholds are used to define these classes as they

refer to proportional change, where a doubling of a species index (an increase of

100%) is counterbalanced by a halving (a decrease of 50%).

What is 'bootstrapping' and why is it used?

Bootstrapping, a statistical method that estimates the uncertainty in a trend through

repeated re-sampling and trend estimation. Confidence intervals for the estimated

trends are calculated from percentiles (such as 2.5% and 97.5%) of the sample of

estimated trend lines. The procedures currently used provide a measure, and level of

confidence, of the indicator value in any particular year (e.g. 2014) relative to the

start year of the time series. It is feasible to calculate the change, and confidence in

that change, for any other time period (e.g. over five years from 2009 to 2014) but

this requires all of the constituent population trends and their bootstraps to be

recalculated using the start year (e.g. 2009) as a baseline.

Why does the overall index for breeding wild birds in England not appear to

reflect the large reductions in the population of farmland birds during the

1980s and why did the population of farmland birds suffer so much during that

time?

55

The overall ‘all-species’ index is comprised of 118 species of birds, all widespread

species with populations of at least 300 breeding pairs for which there are sufficient

data. It represents 4 habitat types (including farmland birds) and a further 31

generalist species with no particular habitat preference. Species trends within this

index vary widely, from species increasing several-fold (e.g. buzzard, Cetti’s warbler,

great spotted woodpecker, and collared dove) to those having declined to less than a

tenth of their 1970 numbers (turtle dove, tree sparrow, willow tit and grey partridge).

Within the index, 32% of the 118 species increased, 35% showed little change and

30% declined between 1970 and 2016. The apparent declines in the farmland birds

indicator (comprising of 19 species, so just 16% of the total species in the all-species

indicator) are being mitigated by increases in some of the other species in the

indicator.

The large declines in the abundance of many farmland birds have many known and

potential causes. For a large part, declines have been caused by the changes in

farming practices that have taken place since the 1950s and 60s, such as the loss of

mixed farming, a move from spring to autumn sowing of arable crops, change in

grassland management (e.g. a switch from hay to silage production), increased

pesticide and fertiliser use, and the removal of non-cropped features such as

hedgerows. The rate of these changes, which resulted in the loss of suitable nesting

and suitable feeding habitats, and a reduction in available food, was greatest during

the late 1970s and early 1980s, the period during which many farmland bird

populations declined most rapidly.

What are the main differences between 'generalist' and 'specialist' bird

populations and why have they fared so differently since the 1970s?

Specialist bird species are considered to be largely or wholly dependent on one

particular habitat whereas generalist bird species utilise a wider range of habitats.

Specialist bird species may find it difficult to adapt to changes in their habitats while

generalist bird species may find it easier to adapt because they are not as reliant on

one specific habitat type. For example, the woodland bird index is comprised of

trends for 34 species. Between 1970 and 2017, the index for woodland specialists

which are highly dependent on woodland habitats declined by 42% while the index

for woodland generalists, many of which have adapted to using gardens and wooded

areas in farmland including woodland, showed a 10% increase.

Are species of birds included in the trends if they are introduced in subsequent

years?

Yes. Species of birds which are introduced into the indices in later years will be

included and trends calculated.

Documents

© Crown copyright 2020 · 2020. 11. 25. · national monitoring schemes1 [Footnote 1: See ‘Main notes’ at the end for more details of the surveys sources used]. Trends in bird