Appendix S2. Details of results.
1. Correlations between environmental variables
Table A1. Pearson’s correlation coefficients between environmental (climatic and oceanic) variables. Only significant correlations are indicated. NAO
denotes the North Atlantic Oscillation index. NAO(t-1) denotes the North Atlantic Oscillation index computed for the 4th quarter of the previous year. SST
and Chl-a denote sea surface temperature and chlorophyll a concentration, respectively.
1st quarter
NAO(t-1)
NAO(t-1)
NAO
1st quarter
SST
2nd quarter
NAO
SST
Chl-a
NAO
SST
0.6
0.76
0.65
0.7
0.62
3rd quarter
Chl-a
NAO
SST
Chl-a
0.86
Chl-a
NAO
2nd quarter
SST
Chl-a
NAO
3rd quarter
SST
Ch-la
0.89
2. Relationship between mate fidelity (FidMate), nest fidelity (FidNest) and breeding
success (BS)
Table A2. Model-averaged partial regression coefficients (β) and unconditional 95% confidence
intervals (CIs) from generalized linear mixed-effects model of mate fidelity (FidMate). The fixed effects
independent variable is pair breeding success (BS). Akaike weight (w) indicates relative importance of
BS based on summing weights across models where BS occurs. Random effects for nest identity
(variance component=0.27) and pair identity (variance component=2.52) were fitted (n=403).
Coefficients are in bold where CIs do not include zero.
Variable
w
β
Lower CI
Upper CI
BS
0.98
1.24
0.43
2.05
Table A3. Model-averaged partial regression coefficients (β) and unconditional 95% confidence
intervals (CIs) from generalized linear mixed-effects model of nest fidelity (FidNest). The fixed effects
independent variable is pair breeding success (BS). Akaike weight (w) indicates relative importance of
BS based on summing weights across models where BS occurs. Random effects for nest identity
(variance component=0.24) and year (variance component=0.39) were fitted (n=445). Coefficients are
in bold where CIs do not include zero.
Variable
w
β
Lower CI
Upper CI
BS
0.96
0.75
0.25
1.25
3. Relationships between nest fidelity (FidNest) and environmental predictors with
separate modeling for successful and unsuccessful pairs
Table A4. Model-averaged partial regression coefficients (β) and unconditional 95% confidence
intervals (CIs) from generalized linear mixed-effects models of nest fidelity (FidNest) with separated
analyses for unsuccessful (n=) and successful (n=) pairs. Fixed effects independent variables of the
model set are the Sea Surface Temperature computed for the 2nd quarter of the year (SST(q2)) and
Chlorophyll a concentration computed for the 2nd and 3rd quarters (Chl-a(q2) and Chl-a(q3)). Akaike
weight (w) indicates relative importance of a given covariate based on summing weights across
models where the covariate occurs. Coefficients are in bold where CIs do not include zero.
Unsuccessful pairs
Successful pairs
Variable
w
β
Lower CI
Upper CI
w
β
Lower CI Upper CI
Chl-a(q3)
0.53
-29.2
-71
12
0.92
-58.3
-89
-27
Chl-a(q2)
0.41
4.5
-3
11
0.33
-3.09
-13.8
7.9
SST(q2)
0.38
-0.5
-1.5
0.53
0.37
-0.77
-2.3
0.82
BSmean
0.28
-1.2
-6.6
4.2
0.28
-2.1
-10
5.8
4. Relationships between nest fidelity (FidNest), breeding success (BS) and three
univariate predictors of BS
(A) 2nd quarter North Atlantic Oscillation index (NAO)
Table A5. Model-averaged partial regression coefficients (β) and unconditional 95% confidence
intervals (CIs) from generalized linear mixed-effects models of mate fidelity (Fidmate, n=403) and nest
fidelity (FidNest, n=445). Fixed effects independent variables of the model set are the pair breeding
success (BS), the NAO index (2nd quarter) and their interaction. Akaike weight (w) indicates relative
importance of a given covariate based on summing weights across models where the covariate
occurs. Coefficients are in bold where CIs do not include zero.
Fidmate
FidNest
Variable
w
β
Lower CI
Upper CI
w
β
Lower CI
Upper CI
BS
0.99
1.22
0.39
2.04
0.99
0.64
0.098
1.17
NAO
0.36
0.16
-0.48
0.81
0.86
-0.08
-0.84
0.68
BS×NAO
0.1
0.14
-1.19
1.47
0.76
-1.21
-2.23
-0.18
(B) 2nd quarter chlorophyll a concentration (Chl-a)
Table A6. Model-averaged partial regression coefficients (β) and unconditional 95% confidence
intervals (CIs) from generalized linear mixed-effects models of mate fidelity (Fidmate, n=403) and nest
fidelity (FidNest, n=445). Fixed effects independent variables of the model set are the pair breeding
success (BS), the chlorophyll a concentration (2nd quarter, Chl-a) and their interaction. Akaike weight
(w) indicates relative importance of a given covariate based on summing weights across models
where the covariate occurs. Coefficients are in bold where CIs do not include zero.
Fidmate
FidNest
Variable
w
β
Lower CI
Upper CI
w
β
Lower CI
Upper CI
BS
0.07
0.82
-1.72
3.36
1.0
3.19
0.94
5.44
Chl-a
0.97
12.52
-3.48
28.5
1.0
-0.36
-5.73
4.99
BS×Chl-a
0.02
6.49
-6.97
19.95
0.94
-8.22
-14.1
-2.27
(C) 3rd quarter chlorophyll a concentration (Chl-a)
Table A7. Model-averaged partial regression coefficients (β) and unconditional 95% confidence
intervals (CIs) from generalized linear mixed-effects models of mate fidelity (Fidmate, n=403) and nest
fidelity (FidNest, n=445). Fixed effects independent variables of the model set are the pair breeding
success (BS), the chlorophyll a concentration (3rd quarter, Chl-a) and their interaction. Akaike weight
(w) indicates relative importance of a given covariate based on summing weights across models
where the covariate occurs. Coefficients are in bold where CIs do not include zero.
Fidmate
FidNest
Variable
w
β
Lower CI
Upper CI
w
β
Lower CI
Upper CI
BS
0.01
-0.73
-10.5
9.02
0.99
3.95
-0.89
8.80
Chl-a
1.0
160.5
-9.73
330.6
1.0
-21.5
-50.9
7.91
BS×Chl-a
0.0
69.2
-71.7
210.2
0.76
-39.4
-76.8
-2.03
5. Comparison of models with various random effects structures
Table A8. AICc of generalized linear mixed-effects models of breeding success (BS) for various model
structures (Year: year factor; IDpair: pair identity; IDnest: nest identity).
Random effects
Degrees of freedom
AICc
IDpair
3
953.9381
Year + IDpair + IDnest
4
955.9021
IDnest
2
959.1305
Year + IDnest
3
961.0354
IDpair
2
979.4369
Year + IDpair
3
981.364
Year
2
992.3991
(none)
1
994.2423