Table 1. Summary of model selection results for logistic regression models predicting hatching success, chick survival, and overall reproductive success in Fork-tailed Storm-Petrel (Oceanodroma furcata) nests at Kasatochi Island, Alaska. Models are listed in order of best fit for each success parameter in each year based on Akaike’s information criterion for small sample sizes (AICc). Except for the null model, only models with ΔAICc < 2.0 are shown. Log(L) is the log-likelihood value, k is the number of parameters in the model, ΔAICc is the difference in AICc value between each model and the top model, wi is the Akaike weight, and R2 is the proportion of the total variation in success explained by the model. Brooding duration (BRD) data are available only for 2006.


Success Year Model log(L) k AICc ΔAICc wi R2
Hatching success
2005 DEP+SLP+VEGH+TEMPR+RH+EGGV
DEP+RH
VEGH+VEGC+RH
SLP+VEGH+TEMPR
Null
-7.33
-12.02
-11.01
-8.97
-35.34
7
3
4
4
1
31.96
32.31
32.47
32.63
72.74
0.00
0.35
0.51
0.67
40.78
0.30
0.25
0.23
0.21
0.00
0.345
0.270
0.232
0.093
0.000
2006 DEP+VEGC+EGGV
EGGV
VEGH+VEGC
Null
-13.60
-14.96
-12.91
-30.53
4
2
3
1
34.61
35.92
36.07
63.10
0.00
1.31
1.46
28.49
0.29
0.15
0.13
0.00
0.217
0.062
0.072
0.000
Chick survival
2005 TEMP
TEMP+EGGV
TEMP+VIS
Null
-28.81
-25.94
-24.49
-48.87
2
3
3
1
57.80
59.13
59.78
99.80
0.00
1.33
1.98
42.00
0.42
0.22
0.16
0.00
0.348
0.368
0.328
0.000
2006 TEMP+BRD
TEMP
TEMP+VIS+BRD
Null
-4.57
-5.49
-4.58
-31.51
3
2
4
1
17.42
19.13
19.22
65.07
0.00
1.71
1.80
47.65
0.39
0.17
0.16
0.00
0.190
0.138
0.145
0.000
Overall reproductive success
2005 TEMP+VIS
TEMP+EGGV
Null
-12.26
-14.62
-57.38
3
3
1
34.96
35.18
116.81
0.00
0.22
81.85
0.45
0.41
0.00
0.328
0.224
0.000
2006 TEMP+BRD
TEMP+VIS+BRD
TEMP+VIS
Null
-5.39
-5.05
-8.00
-48.41
3
4
3
1
20.19
20.45
22.12
99.05
0.00
0.26
1.93
78.86
0.39
0.34
0.15
0.00
0.140
0.145
0.144
0.000

†BRD: brooding duration; DEP: chamber depth; EGGV: egg volume; RH: relative humidty; SLP: slope; TEMP: temperature; TEMPR: temperature range; VEGC: vegetation cover; VEGH: vegetation height; VIS: visitation rate