Table S1. Mean annual sample size (± SE) for each response variable. Fledglings per
breeding attempt (FBPA) is a function of clutch size, brood size and egg and chick stage
failure rates, and the sample size for this variable is thus conservatively calculated as that
relating to the variable from this set with the smallest sample size. No years were excluded
from the spotted flycatcher dataset, but data were excluded from years with fewer than 20 and
1st egg date
Redstart
Clutch size
Brood size
FBPA
66.7 ± 4.9; n = 35
53.6 ± 3.3; n = 36
127.3 ± 7.0; n = 36
42.5 ± 2.4; n = 28
Spotted flycatcher 71.8 ± 2.9; n = 36
80.2 ± 3.1; n = 36
199.8 ± 9.1; n = 36
57.6 ± 2.5; n = 36
Wood warbler
27.5 ± 3.5; n = 15
57.3 ± 5.6; n = 36
16.6 ± 2.0; n = 18
36.4 ± 3.5; n = 30
15 samples respectively for redstart and wood warbler.
Table S2 List of transformations to ensure that predictors used in the models presented in
Tables 1 and 2 of the main manuscript did not exhibit significant skew, in addition redstart
lay date was transformed using a natural log, and wood warbler clutch size was square root
transformed.
Species
Redstart
Spotted
flycatcher
Wood warbler
Predictor
Winter precipitation
Nesting precipitation
Nesting precipitation
Model
All response variables
All except clutch size
All except clutch size
Transformation
Ln
Square root
Square root
Nesting precipitation
Chick rearing
temperature
Chick precipitation
Nesting precipitation
Nesting precipitation
Clutch size
Brood size and FBPA
Ln
Square root
Brood size
Lay date
Clutch size and FBPA
Square root
Square root
Ln
Table S3 R2 values of multiple regressions of each response variable, i.e. first egg date, clutch
size, brood size and fledgings per breeding attempt (FBPA), against winter temperature and
precipitation in each of the potential winter distributions (note that the restricted and maximum
ranges were identical for spotted flycatcher). Asterisks denote the winter distribution that
generated the highest r2 value for each response variable. For redstart, winter precipitation from
restricted and maximum ranges and quartiles 1, 2 and 3 were ln transformed, and precipitation
from quartile 4 was square-root transformed. For spotted flycatcher winter precipitation was ln
transformed for quartile 1 and square-root transformed for quartile 2. For the wood warbler lay
date model temperature in the maximum winter range, and quartiles 1 and 2 was ln transformed;
in the brood size model temperature and precipitation in quartile 2 were ln transformed; in the
FBPA model temperature in the maximum range and quartile 1, and precipitation in quartile 2
were ln transformed.
response
restricted maximum quartile 1 quartile 2 quartile 3 quartile 4
variable
first egg
0.14
0.07
0.15
*0.15
0.13
0.14
date
redstart
clutch size
0.02
0.02
0.01
0.03
*0.08
0.01
brood size
0.04
0.04
0.04
0.05
0.05
*0.05
FPBA
0.13
0.07
0.08
0.15
*0.15
0.09
first egg
0.05
0.08
*0.24
0.06
0.03
date
spotted
clutch
*0.13
0.07
0.04
0.05
0.09
flycatcher size
brood size
0.30
0.35
*0.39
0.36
0.34
FPBA
0.05
*0.06
0.06
0.05
0.05
first egg
*0.11
0.04
0.01
<0.01
0.02
0.03
date
wood
clutch size
*0.08
0.03
0.02
0.03
0.06
0.02
warbler
brood size
0.01
0.02
*0.11
0.01
0.06
<0.01
FPBA
0.03
0.03
0.05
*0.10
0.01
0.06
species
Table S4 Pearson’s correlation coefficients between climatic variables used as predictors in
multiple regression analyses; asterisks denote significant correlations (* P < 0.05, ** P < 0.01,
*** P < 0.001; not corrected for multiple comparisons). See Table S3 for list of transformations.
redstart
lay date
winter temp
winter
precipitation
+0.08
passage
temperature
+0.41*
passage
precipitation
-0.33
Sahel
rainfall
-0.09
early spring
temperature
+0.31
nesting
temperature
+0.15
nes
precip
+0
winter precip
-
-0.09
-0.13
+0.28
+0.00
-0.21
-0
passage temp
-
-
-0.42**
-0.09
+0.30
-0.11
+0
passage precip
-
-
-
+0.22
+0.19
+0.32
-0
Sahel rainfall
-
-
-
-
+0.13
+0.09
+0
early spring temp
-
-
-
-
-
+0.53***
-0
redstart
clutch size
redstart
brood size
redstart
FPBA
nesting temp
-
-
-
-
-
-
-0
winter temp
+0.08
+0.41*
-0.34
-0.10
+0.35*
+0.20
+0
winter precip
-
-0.08
-0.11
+0.32
+0.01
-0.20
-0
passage temp
-
-
-0.46**
-0.11
+0.28
-0.11
+0
passage precip
-
-
-
+0.17
+0.16
+0.28
-0
Sahel rainfall
-
-
-
-
+0.08
+0.05
+0
early spring temp
-
-
-
-
-
+0.56***
-0
nesting temp
-
-
-
-
-
-
-0
winter temp
+0.08
+0.40*
-0.31
-0.09
+0.29
+0.12
+0
winter precip
-
-0.07
-0.15
+0.28
+0.00
-0.17
-0
passage temp
-
-
-0.46**
-0.08
+0.27
-0.05
+0
passage precip
-
-
-
+0.20
+0.20
+0.19
-0
Sahel rainfall
-
-
-
-
+0.15
+0.11
+0
early spring temp
-
-
-
-
-
+0.49**
-0
nesting temp
-
-
-
-
-
-
-0
nesting precip
-
-
-
-
-
-
chick rearing temp
-
-
-
-
-
-
winter temp
+0.08
+0.41*
-0.34*
-0.10
+0.30
+0.04
-0
winter precip
-
-0.08
-0.11
+0.32
+0.01
-0.22
-0
passage temp
-
-
-0.46**
-0.11
+0.34
-0.16
+0
passage precip
-
-
-
+0.17
+0.19
+0.38*
-0
Sahel rainfall
-
-
-
-
+0.22
+0.18
+0
early spring temp
-
-
-
-
-
+0.53**
-0
nesting temp
-
-
-
-
-
-
-0
nesting precip
-
-
-
-
-
-
winter temp
winter
precipitation
-0.01
passage
temperature
+0.56***
passage
precipitation
-0.33
Sahel
rainfall
-0.12
early spring
temperature
+0.26
nesting
temperature
+0.23
winter precip
-
-0.01
-0.06
+0.30
-0.07
+0.29
-0
passage temp
-
-
-0.45**
+0.21
+0.33*
+0.31
-0
passage precip
-
-
-
+0.19
+0.21
+0.07
+0
Sahel rainfall
-
-
-
-
+0.27
+0.20
-0
early spring temp
-
-
-
-
-
+0.19
+0
nesting temp
-
-
-
-
-
-
-0.4
winter temp
-0.01
+0.56***
-0.33
-0.12
+0.23
+0.22
+0
winter precip
-
-0.01
-0.06
+0.30
-0.07
+0.29
-0
passage temp
-
-
-0.45**
+0.21
+0.30
+0.29
-0
passage precip
-
-
-
+0.19
+0.21
+0.08
+0
Sahel rainfall
-
-
-
-
+0.26
+0.18
-0
early spring temp
-
-
-
-
-
+0.17
+0
nesting temp
-
-
-
-
-
-
-0.4
chick rearing temp
spotted
flycatcher
lay date
spotted
flycatcher
clutch size
nes
precip
+0
spotted
flycatcher
brood size
spotted
flycatcher
FPBA
winter temp
-0.01
+0.56***
-0.33
-0.12
+0.26
+0.24
+0
winter precip
-
-0.01
-0.06
+0.30
-0.08
+0.28
-0
passage temp
-
-
-0.45**
+0.21
+0.35*
+0.33*
-0
passage precip
-
-
-
+0.19
+0.18
+0.04
+0
Sahel rainfall
-
-
-
-
+0.28
+0.19
-0
early spring temp
-
-
-
-
-
+0.15
+0
nesting temp
-
-
-
-
-
-
-0.5
nesting precip
-
-
-
-
-
-
chick rearing temp
-
-
-
-
-
-
winter temp
-0.01
+0.56***
-0.33
-0.12
+0.25
+0.24
+0
winter precip
-
-0.01
-0.06
+0.30
-0.08
+0.29
-0
passage temp
-
-
-0.45**
+0.21
+0.34*
+0.34*
-0
passage precip
-
-
-
+0.19
+0.20
+0.06
+0
Sahel rainfall
-
-
-
-
+0.28
+0.21
-0
early spring temp
-
-
-
-
-
+0.16
+0
nesting temp
-
-
-
-
-
-
-0.4
nesting precip
-
-
-
-
-
-
winter temp
winter
precipitation
+0.02
passage
temperature
+0.33
passage
precipitation
-0.29
Sahel
rainfall
-0.02
early spring
temperature
+0.11
nesting
temperature
-0.00
winter precip
-
-0.08
-0.14
+0.32
-0.06
+0.11
-0
passage temp
-
-
-0.25
+0.14
+0.33
+0.16
+0
passage precip
-
-
-
+0.27
+0.17
+0.19
-0
Sahel rainfall
-
-
-
-
+0.35
+0.30
+0
early spring temp
-
-
-
-
-
+0.59***
-0
nesting temp
-
-
-
-
-
-
-0.
winter temp
+0.05
+0.37
-0.35
+0.02
+0.23
-0.06
+0
winter precip
-
-0.37
+0.09
+0.27
-0.18
-0.13
+0
passage temp
-
-
-0.36
-0.45
+0.34
-0.01
+0
passage precip
-
-
-
+0.45
+0.40
+0.70**
-0
Sahel rainfall
-
-
-
-
+0.34
+0.37
-0
early spring temp
-
-
-
-
-
+0.60*
-0.6
nesting temp
-
-
-
-
-
-
-0.
winter temp
-0.01
+0.50**
-0.39*
-0.12
+0.15
+0.15
+0
winter precip
-
-0.12
-0.04
+0.30
-0.05
+0.14
+0
passage temp
-
-
-0.41*
+0.05
+0.32
+0.17
+0
passage precip
-
-
-
+0.21
+0.14
+0.14
-0
Sahel rainfall
-
-
-
-
+0.26
+0.21
+0
early spring temp
-
-
-
-
-
+0.54***
-0
nesting temp
-
-
-
-
-
-
-0
nesting precip
-
-
-
-
-
-
chick rearing temp
wood
warbler
lay date
wood
warbler
clutch size
wood
warbler
brood size
nes
precip
+0
chick rearing temp
wood
warbler
FPBA
-
-
-
-
-
-
winter temp
+0.19
+0.31
-0.37
+0.03
+0.12
-0.12
+0
winter precip
-
-0.14
-0.21
+0.21
-0.10
-0.00
+0
passage temp
-
-
-0.28
+0.03
+0.23
+0.12
+0
passage precip
-
-
-
+0.30
+0.25
+0.22
-0
Sahel rainfall
-
-
-
-
+0.31
+0.47*
+0
early spring temp
-
-
-
-
-
-0.65**
-0.6
nesting temp
-
-
-
-
-
-
-0.
nesting precip
-
-
-
-
-
-
chick rearing temp
-
-
-
-
-
-