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
0
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