Table 1 Foraging trip characteristics (mean ± SE) of red-footed and brown boobies by sex, and results of GLMMs

n (birds / trips)

5 / 8

19 / 46

24 / 54

27 / 124

31 / 93

58 / 217

–

–

–

Max dist. (km)

90.4 ± 34.0

57.4 ± 6.9

62.3 ± 7.7^b

14.8 ± 1.4^a

23.5 ± 1.7^a

18.5 ± 1.1^b

1.191 (0.275)^g

7.496 (0.006)

22.491 (< 0.001)

Dist. coast (km)

44.0 ± 17.0

31.8 ± 0.3

33.6 ± 3.8^b

4.5 ± 0.9^a

11.3 ± 0.1^a

7.4 ± 0.7^b

0.539 (0.463)

6.298 (0.012)

28.91 (< 0.001)

Total dist. (km)

252.1 ± 83.4

194.5 ± 22.9

203.0 ± 22.8^b

49.9 ± 3.9^a

77.2 ± 5.5^a

61.6 ± 3.4^b

0.472 (0.492)

5.729 (0.017)

26.33(< 0.001)

Trip dur. (h)

14.6 ± 5.4

12.4 ± 1.8

12.7 ± 1.7^b

3.0 ± 0.3^a

4.4 ± 0.4^a

3.6 ± 0.3^b

0.041 (0.840)^g

4.311 (0.038)^g

21.40 (< 0.001)

Prop. time forage*

0.41 ± 0.03

0.52 ± 0.02

0.50 ± 0.02

0.50 ± 0.02

0.50 ± 0.02

0.50 ± 0.01

3.807 (0.051)

0.141 (0.708)

0.230 (0.631)

Prop. time travel*

0.39 ± 0.03

0.29 ± 0.01

0.31 ± 0.01

0.32 ± 0.02

0.36 ± 0.02

0.34 ± 0.01

0.005 (0.945)

1.448 (0.229)

Prop. time rest*

0.23 ± 0.04

0.19 ± 0.02

0.20 ± 0.02

0.21 ± 0.02

0.17 ± 0.02

0.20 ± 0.01

0.885 (0.347)

1.653 (0.199)

0.964 (0.326)

Core HR (km²)

143.5 ± 66.3

61.2 ± 11.3

73.4 ± 14.0^b

15.3 ± 3.4

30.4 ± 4.1

21.8 ± 2.7^b

1.550 (0.213)

1.034 (0.309)

9.197 (0.002)

Main HR (km²)

827.3 ± 424.9

335.7 ± 71.9

408.5 ± 88.6^b

58.2 ± 11.7

121.2 ± 14.4

85.2 ± 9.3^b

1.366 (0.242)

1.853 (0.173)

0.704 (0.001)

Bathymetry (m)

2023 ± 476.0

2321 ± 209

2277 ± 190^b

793 ± 98^a

1634. ± 125^a

1153 ± 82^b

0.362 (0.548)

12.342 (< 0.001)

13.043 (< 0.001)

Dives hr.⁻¹

8.8 ± 2.8

6.7 ± 1.4

7.4 ± 1.3

7.2 ± 1.1

7.2 ± 0.9

7.2 ± 0.7

0.027 (0.868)

0.991 (0.970)

Max dive depth (m)

0.42 ± 0.03

0.50 ± 0.05

0.47 ± 0.03^b

0.73 ± 0.05

0.73 ± 0.04

0.73 ± 0.03^b

0.388 (0.534)

0.013 (0.909)

16.219 (< 0.001)

Dive dur. (s)

5.8 ± 1.6

4.2 ± 1.7

4.8 ± 1.3

5.1 ± 2.2

2.1 ± 0.3

3.7 ± 1.2

0.591 (0.442)

1.702 (0.192)

1.171 (0.279)