Ecological Archives E096-008-A1

He Zhang, Oscar Vedder, Peter H. Becker, and Sandra Bouwhuis. 2015. Contrasting between- and within-individual trait effects on mortality risk in a long-lived seabird. Ecology 96:7179. http://dx.doi.org/10.1890/14-0064.1

Appendix A. Contrasting between- and within-individual trait effects on mortality risk in a long-lived seabird.

Supplementary information regarding the between- and within-individual effects of ten phenotypic traits on mortality risk in the Common Tern, with descriptive statistics of the ten phenotypic traits (Table A1), information on our assessment of death (Table A2), quantification of between-trait correlations (Table A3), model comparison of models used to select forms of sex, recruitment age and frailty prior to assessing trait effects on mortality risk (Table A4) and a report on the estimated effects of the traits on mortality risk (Table A5).

Table A1. Descriptive statistics (mean and SD) for raw data, between- and within-individual components of each phenotypic trait.

Trait

Raw data

Between-
individual component

Within-
individual component

Age-corrected within-
individual component

 

mean

SD

mean

SD

mean

SD

mean

SD

Arrival date

120.60

12.65

120.60

7.93

0.00

9.86

0.00

8.33

Arrival mass

130.93

8.29

130.93

6.47

0.00

5.19

0.00

5.16

Breeding probability

0.90

0.31

0.90

0.21

0.00

0.23

0.00

0.23

Laying date

142.78

12.43

142.78

7.58

0.00

9.86

0.00

8.10

Egg volume

38.50

2.72

38.50

2.07

0.00

1.76

0.00

1.71

Clutch size

2.52

0.63

2.52

0.34

0.00

0.52

0.00

0.50

Brood size

1.83

1.07

1.83

0.58

0.00

0.90

0.00

0.90

Hatching success

0.74

0.36

0.74

0.19

0.00

0.31

0.00

0.30

Rearing success

0.44

0.38

0.44

0.19

0.00

0.33

0.00

0.32

No. of fledglings

0.69

0.80

0.69

0.38

0.00

0.70

0.00

0.70

 

Table A2. Assessment of the reliability of assuming a bird to be dead after not having observed it, based on the observation histories up to 2013 of 782 common terns that bred between 1993 and 2011: after first reproduction, 96% of breeders do not skip observation for two or more consecutive years.

Max. no. of consecutive gaps

No. of birds

% of birds

0

732

93.6

1

20

2.6

2

14

1.8

3+

16

2.0

 

Table A3. Between-trait correlations for the between- (lower triangular matrix) and within-individual trait components (upper triangular matrix). Reported are the correlation coefficient r and p value obtained using Kendall's method, as well as, between brackets, the r² value based on the Pearson correlation coefficient. Note that, for the within-individual components, only one combination of records was randomly selected for each individual to calculate the correlation to avoid bias due to the fact that individuals differ in their number of within-individual observations due to variation in lifespan.

 

Arrival date

Arrival mass

Breeding probability

Laying date

Egg volume

Clutch size

Brood size

Hatching success

Rearing success

No. of fledglings

 

r (r²)

p

r (r²)

p

r (r²)

p

r (r²)

p

r (r²)

p

r (r²)

p

r (r²)

p

r (r²)

p

r (r²)

p

r (r²)

p

Arrival date

 

 

-0.078 (0.014)

0.032

-0.013 (0.013)

0.649

0.435 (0.333)

<0.001

-0.195 (0.083)

<0.001

-0.203 (0.101)

<0.001

-0.224 (0.097)

<0.001

-0.179 (0.056)

<0.001

-0.152 (0.037)

<0.001

-0.203 (0.068)

<0.001

Arrival mass

-0.181 (0.052)

<0.001

 

 

-0.002 (0.001)

0.969

-0.041 (0.003)

0.270

0.042 (0.002)

0.264

0.077 (0.014)

0.042

0.074 (0.013)

0.052

0.042 (0.006)

0.259

0.009 (0.001)

0.833

0.031 (0.006)

0.409

Breeding probability

-0.112 (0.034)

<0.001

0.014 (0.001)

0.641

 

 

-0.001 (0.001)

0.981

0.069 (0.005)

0.018

0.008 (0.001)

0.800

0.016 (0.001)

0.592

0.032 (0.001)

0.281

-0.024 (0.001)

0.453

-0.002 (<0.001)

0.936

Laying date

0.582 (0.624)

<0.001

-0.165 (0.051)

<0.001

-0.141 (0.048)

<0.001

 

 

-0.267 (0.099)

<0.001

-0.344 (0.271)

<0.001

-0.306 (0.210)

<0.001

-0.184 (0.109)

<0.001

-0.185 (0.051)

<0.001

-0.269 (0.127)

<0.001

Egg volume

-0.105 (0.036)

<0.001

0.066 (0.015)

0.011

0.049 (0.002)

0.071

-0.077 (0.034)

0.001

 

 

0.149 (0.032)

<0.001

0.141 (0.031)

<0.001

0.086 (0.019)

0.001

0.037 (<0.001)

0.192

0.132 (0.022)

<0.001

Clutch size

-0.237 (0.160)

<0.001

0.114 (0.030)

<0.001

0.059 (0.022)

0.038

-0.358 (0.303)

<0.001

0.001 (0.002)

0.966

 

 

0.426 (0.321)

<0.001

0.137 (0.059)

<0.001

0.005 (0.001)

0.872

0.176 (0.073)

<0.001

Brood size

-0.197 (0.088)

<0.001

0.051 (0.007)

0.055

0.046 (0.013)

0.104

-0.328 (0.206)

<0.001

0.021 (0.002)

0.401

0.463 (0.353)

<0.001

 

 

0.656 (0.720)

<0.001

0.041 (0.004)

0.151

0.336 (0.220)

<0.001

Hatching success

-0.080 (0.028)

0.001

-0.015 (<0.001)

0.568

0.043 (0.009)

0.130

-0.167 (0.075)

<0.001

0.019 (0.003)

0.442

0.134 (0.047)

<0.001

0.652 (0.699)

<0.001

 

 

0.041 (0.002)

0.156

0.269 (0.156)

<0.001

Rearing success

-0.163 (0.041)

<0.001

0.088 (0.011)

0.001

0.074 (0.010)

0.011

-0.252 (0.078)

<0.001

0.013 (<0.001)

0.619

0.127 (0.019)

<0.001

0.097 (0.013)

<0.001

0.043 (0.005)

0.098

 

 

0.376 (0.236)

<0.001

No. of fledglings

-0.204 (0.060)

<0.001

0.081 (0.012)

0.003

0.075 (0.012)

0.009

-0.333 (0.151)

<0.001

0.070 (0.006)

0.005

0.279 (0.131)

<0.001

0.437 (0.309)

<0.001

0.315 (0.183)

<0.001

0.558 (0.457)

<0.001

 

 

 

Table A4. Generalized AIC values with degrees of freedom (df) between brackets, as obtained for models used to first select the best form for sex and recruitment age (RA; columns 1–4), then to select a frailty term (columns 5–6), before obtaining the results for effects of between- and within-individual effects (B and W, respectively) of 10 phenotypic traits on mortality risk in up to 782 common terns, as reported in table 1 in the main paper. The best performing models with the lowest AIC for each trait are indicated in bold. Note that sample sizes for each trait are identical to those presented in table 1 in the main manuscript and are therefore not reported here.

Model

B+W

B+W+
sex+RA

B*sex*RA+
W*sex*RA

B+W+
strata(sex,RA)

Frailty
(ID)

Frailty
(year)

Arrival date

4824 (2)

4831 (9)

4807 (23)

3310 (2)

3298 (110)

3289 (11)

Arrival mass

2244 (2)

2249 (9)

2269 (23)

1507 (2)

1507 (2)

1492 (12)

Breeding probability

5826 (2)

5830 (9)

5835 (23)

4077 (2)

4077 (2)

4054 (12)

Laying date

4511 (2)

4501 (9)

4501 (23)

3068 (2)

3068 (2)

3036 (13)

Egg volume

4741 (2)

4740 (9)

4744 (23)

3302 (2)

3302 (2)

3288 (11)

Clutch size

4715 (2)

4713 (9)

4719 (23)

3272 (2)

3272 (2)

3259 (11)

Brood size

4745 (2)

4744 (9)

4763 (23)

3306 (2)

3306 (2)

3293 (11)

Hatching success

4780 (2)

4780 (9)

4801 (23)

3343 (2)

3343 (2)

3329 (11)

Rearing success

3734 (2)

3738 (9)

3756 (23)

2569 (2)

2569 (2)

2561 (8)

No. of fledglings

4751 (2)

4750 (9)

4764 (23)

3312 (2)

3312 (2)

3299 (10)

 

Table A5. Original (without separation of between- and within-individual trait components) as well as standardized effects for each of ten phenotypic traits on mortality risk in up to 782 common terns. Note that sample sizes and p values of the standardized effects are identical to those presented in table 1 in the main manuscript and are therefore not reported here.

 

Original effects without separation
of between- and within-individual effects

Standardized effects

Trait

Between-individual effect

Within-individual effect

Age-corrected
within-individual effect

 

E

SE

p

E

SE

E

SE

E

SE

Arrival date

0.015

0.004

<0.001

0.488

0.044

-0.335

0.065

-0.256

0.063

Arrival mass

-0.006

0.009

0.510

-0.203

0.073

0.193

0.074

0.127

0.074

Breeding probability

-0.545

0.126

<0.001

0.053

0.048

-0.261

0.041

-0.214

0.041

Laying date

-0.002

0.006

0.790

0.435

0.052

-0.893

0.089

-0.470

0.070

Egg volume

0.006

0.019

0.750

-0.189

0.052

0.244

0.050

0.169

0.049

Clutch size

0.015

0.091

0.870

-0.356

0.047

0.300

0.059

0.155

0.057

Brood size

-0.014

0.051

0.780

-0.311

0.051

0.186

0.055

0.045

0.054

Hatching success

-0.081

0.144

0.570

-0.171

0.048

0.077

0.052

0.006

0.052

Rearing success

0.102

0.161

0.530

-0.283

0.059

0.216

0.060

0.011

0.060

No. of fledglings

0.024

0.072

0.740

-0.318

0.057

0.193

0.057

0.004

0.056


[Back to E096-008]