Ecological Strategies of Northeastern Scrub-shrub Birds

Scott Schlossberg David KingDept. of Nat. Res. Conservation U.S. Forest Service

University of Massachusetts Northern Research Station

Shrubland birds

Shrubland management, 12000 BC

R. Askins, Restoring North America’s Birds, 2000

Shrubland management now

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5

10

15

20

25

30

1940 1960 1980 2000

Year

Ear

ly-s

ucc

essi

on

al f

ore

st(%

of

all

fore

st)

Conn. Mass. Rhode Island

USFS Forest Inventory & Analysis

1960 1970 1980 1990 2000 2010Year

0.0

0.5

1.0

1.5

2.0C

ount

inde

x

1960 1970 1980 1990 2000 2010Year

3

4

5

6

7

8

9

10

11

Cou

nt in

dex

1960 1970 1980 1990 2000 2010Year

0

5

10

15

20

25

Cou

nt in

dex

1960 1970 1980 1990 2000 2010Year

0

1

2

3

4

5

Cou

nt in

dex

1960 1970 1980 1990 2000 2010Year

10

15

20

25C

ount

inde

x

1960 1970 1980 1990 2000 2010Year

0.00

0.05

0.10

0.15

Cou

nt in

dex

Brown Thrasher

FieldSparrow

Chestnut-sided Warbler

EasternTowhee

CommonYellowthroat

Golden-winged Warbler

Questions

• What ecological strategies do shrubland birds follow?

• How can we take advantage of those strategies to manage bird populations?

Forests and shrublands

high

uncommon

large

permanent

Forests

Habitat extent

Edges

Patch size

Patch lifespan

low

prominent

small

~20 years

Shrublands

Ecological strategies of shrubland birds

1. Generalized habitat preferences

2. High dispersal rate

3. Indifferent or attracted to edges

4. Insensitive to patch size

1. Generalized habitat preferences

2. High dispersal rate

3. Indifferent or attracted to edges

4. Insensitive to patch size

Ecological strategies of shrubland birds

Silvicultural openings vs. old fields

Silvicultural openings vs. old fields

0.0

0.2

0.4

0.6

0.8

1.0

Chestnut-sided

warbler

Black-and-white

warbler

Songsparrow

Indigobunting

Bir

d a

bu

nd

ance

Silvicultural

Old field

King et al, For. Ecol. Mgmt., 2009

Aber, Ecology 1979 60:18-23

Succession

Schlossberg & King, J. Wildl. Mgmt. 2009

Year after logging

Rel

ativ

e ab

unda

nce

Succession

0.0

0.4

0.8

1.2

1.6

0 1 2 3

Estimated abundance in wetlands

Est

imat

ed a

bu

nd

ance

in

u

pla

nd

s

Birds in wetlands and uplands

Ecological strategies of shrubland birds

1. Generalized Specialized habitat preferences

2. High dispersal rate

3. Indifferent or attracted to edges

4. Insensitive to patch size

Ecological strategies of shrubland birds

1. Generalized Specialized habitat preferences

2. High dispersal rate

3. Indifferent or attracted to edges

4. Insensitive to patch size

Successional stage: early late

Dispersal rate: high low

Forest ShrublandHabitat

0.0

0.5

1.0R

etur

n ra

te

Schlossberg, Condor, 2009

Mean return rates:

Forest = 0.36

Shrubland = 0.35

Ecological strategies of shrubland birds

1. Generalized Specialized habitat preferences

2. High Typical dispersal rate

3. Indifferent or attracted to edges

4. Insensitive to patch size

Ecological strategies of shrubland birds

1. Generalized Specialized habitat preferences

2. High Typical dispersal rate

3. Indifferent or attracted to edges

4. Insensitive to patch size

Whitcomb et al., Forest Island Dynamics

Indigo BuntingNorthern Cardinal

Meta-analysis

• Studies: report bird abundance in edges and interiors of regenerating clearcuts in the eastern U.S.

• Edge: within 30 m of forest edge

• Interior: ≥ 60 m into clearcut

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Species

Eff

ect

size

(95%

CI)

avoidsedges

prefersedges

Ecological strategies of shrubland birds

1. Generalized Specialized habitat preferences

2. High Typical dispersal rate

3. Indifferent or attracted to Avoid edges

4. Insensitive to patch size

Ecological strategies of shrubland birds

1. Generalized Specialized habitat preferences

2. High Typical dispersal rate

3. Indifferent or attracted to Avoid edges

4. Insensitive to patch size

Seymour et al., For. Ecol. Mgmt. 2003

0.0001

0.001

0.01

0.1

1

10

100

1000

10000

1 10 100 1000 10000

Return interval (yrs)

Are

a (

ha

)

Naturalcanopygaps

Severe fireand wind

Disturbance dynamics in eastern forests

Birds in clearcuts and groupcuts

Costello et al. 2000

Annand and Thompson

1997

Kerpez 1994 Rodewald and

Vitz 2005

Alder flycatcher

Blue-winged warbler

Black-and-white warbler

Cedar waxwing

Common yellowthroat

Chestnut-sided warbler

Field sparrow

Indigo bunting

Mourning warbler

Prairie warbler

Birds in clearcuts and groupcuts

Schlossberg and King 2007

Costello et al. 2000

Annand and Thompson

1997

Kerpez 1994 Rodewald and

Vitz 2005

Alder flycatcher CC

Blue-winged warbler CC CC

Black-and-white warbler

CC CC CC

Cedar waxwing CC

Common yellowthroat CC CC

Chestnut-sided warbler CC

Field sparrow CC CC CC

Indigo bunting CC CC CC CC

Mourning warbler CC

Prairie warbler CC CC CC

Birds in clearcuts and groupcuts

0.0

0.3

0.6

0.9

1.2

1.5

1.8

0 20 40 60 80 100

Right-of-way width (m)

Pre

dic

ted

bir

ds

per

po

int

American Goldfinch

Cedar Waxwing

Chestnut-sided Warbler

Eastern Towhee

Field Sparrow

Prairie Warbler

Bird abundances in rights-of-way

Ecological strategies of shrubland birds

1. Generalized Specialized habitat preferences

2. High Typical dispersal rate

3. Indifferent or attracted to Avoid edges

4. Insensitive to patch size Area-sensitive

Ecological strategies of shrubland birds

1. Specialized habitat preferences

2. Typical dispersal rate

3. Avoid edges

4. Area-sensitive

Management implications

1. Diversity of approaches

Management implications

1. Diversity of approaches

2. Larger openings better

Small openings create more fragmentation

16 ha affected

40 ha affected

1 clearcut, 9 ha9 groupcuts, 1-ha each

King et al. 1998

Management implications

1. Diversity of approaches

2. Larger openings better

3. Simple shapes to minimize edge

Mitchell et al. 2003

Management implications

1. Diversity of approaches

2. Larger openings better

3. Simple shapes to minimize edge

4. Partial cutting is not a panacea

What we need to know

• Landscape ecology

• Nesting success

• Post-fledging ecology

0

1

2

3

4

5

BHVI BLBW BTBW BTNW HETH MYWA OVEN REVI SWTH VEER

Species

Ab

un

da

nc

e

Forest

Wildlife opening

Clearcut

Post-fledging habitat use by forest birds

C. Chandler, thesis, 2007

King et al., J. Zoology, 2006Fink, thesis, 2003

0.0

0.2

0.4

0.6

0.8

1.0

Fragmented Unfragmented

P (

surv

ival

to

13

wee

ks)

low?

high?

Post-fledging survival

???

???

Population growth rate

high

low

Nest success

Acknowledgments

• Natural Resources Conservation Service, Inventory & Assessment Division

• U.S. Fish & Wildlife Service

• C. Chandler, R. Chandler, B. Mazzei

0.5 1.0 2.0 5.0 10.0 20.0

0.0

0.2

0.4

0.6

0.8

1.0

Patch area (acres)

Ch

est

nu

t-si

de

d W

arb

ler R^2 = 0.55

p < 0.01

0.5 1.0 2.0 5.0 10.0 20.0

0.0

0.2

0.4

0.6

0.8

1.0

Patch area (acres)

Co

mm

on

Ye

llow

thro

at

R^2 = 0.83p < 0.01

0.5 1.0 2.0 5.0 10.0 20.0

0.0

0.2

0.4

0.6

0.8

1.0

Patch area (acres)

Ind

igo

Bu

ntin

g

R^2 = 0.70p < 0.01

Area sensitivity in wildlife openings

R. Chandler, thesis, 2006

Litvaitis 2003

Shrubland management now

Study Study location Study sites

DeGraaf 1992 New Hampshire 8

Fink et al. 2006 Missouri 6

Rodewald & Vitz 2005 Ohio 24

Talbott & Yahner 2003 Pennsylvania 20

Yahner 1987 Pennsylvania 6

Elliott 1987 Maine 8

Kerpez 1994 Virginia 8

0

5

10

15

20

25

Forest edge Edge-interior Forestinterior

Forest habitat classification

Nu

mb

er

of

sh

rub

lan

d s

pe

cie

s

Imbeau et al., Ecography 2003

Evidence from western birds