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Electronic Supplementary Material: Adélie penguin (Pygoscelis adeliae) survival rates and their
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relationship to environmental indices in the South Shetland Islands, Antarctica
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Jefferson T. Hinke · Susan G. Trivelpiece · Wayne Z. Trivelpiece
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The supplementary material presents methods and results from double banding study (Part 1) and a long-
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term study of return rates of banded adult Adélie penguins to breeding colonies (Part 2).
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Part 1. Double banding study to estimate the retention rates of aluminum and stainless steel bands
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In the austral spring of 2000, 200 nesting male Adélie penguins (Pygoscelis adeliae) were implanted with
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a passive integrated transponder (PIT tags). The PIT tags were placed under the skin of the lower
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neck/upper back with a sterile, single-use hypodermic applicator. Of the 200 penguins with PIT tags, 100
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also received an aluminum flipper band and another 100 received a stainless steel flipper band. Male
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Adélie penguins were chosen for the study because they exhibit high nest site fidelity, returning to the
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same nest location with >90% probability in subsequent years (Trivelpiece and Trivelpiece 1990). Such
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high nest fidelity helps ensure recapture of as many individuals as possible. The following spring, the
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study colonies were visually searched for banded birds and a hand-held receiver was used to scan all
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individuals in the study colony, both banded and unbanded, for PIT tags. The resulting recapture data are
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presented in Table A1.
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Band retention rates were estimated following the method of Kendall et al. (2009). The probabilities of
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retaining the flipper band (θf) or the pit tag (θp) are estimated by iteratively solving the following system
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of equations for each band type. Example R code is provided:
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lnl=function(beta,n1,n2)
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{
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p=plogis(beta)
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-n1[1]*log(p[1]*p[3]/(1-(1-p[1])*(1-p[3])))-
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n1[2]*log(p[1]*(1-p[3])/(1-(1-p[1])*(1-p[3])))-
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n1[3]*log((1-p[1])*p[3]/(1-(1-p[1])*(1-p[3])))-
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n2[1]*log(p[2]*p[4]/(1-(1-p[2])*(1-p[4])))-
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n2[2]*log(p[2]*(1-p[4])/(1-(1-p[2])*(1-p[4])))-
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n2[3]*log((1-p[2])*p[4]/(1-(1-p[2])*(1-p[4])))
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}
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mod=optim(c(0,0,0,0),lnl,n1=c(13,2,9),n2=c(29,3,1),hessian=T)
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se.beta=sqrt(diag(solve(mod$hessian)))
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se.beta/mod$par
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estimates=plogis(mod$par)
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lcl=plogis(mod$par - 1.96*se.beta )
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ucl=plogis(mod$par + 1.96*se.beta
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cbind(estimates,lcl,ucl)
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The retention rate of aluminum flipper bands were estimated to be 0.6 (95%CI : 0.39 -0.77), while
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stainless steel retention rates were much higher at 0.97 (95%CI : 0.79-0.99). The difference between
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bands is significant ( χ2 = 11.4, df =1, p = 0.0007)
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Part 2. Long-term study of overwinter return rates of aluminum and stainless steel bands on adult Adélie
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Penguins.
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Studies of reproductive performance of Adélie penguins at Admiralty Bay since the 1998/99 austral
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summer (see Hinke eta l. 2007 for description of methods) have used both aluminum and stainless steel
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flipper bands to identify males and females at approximately 100 study nests each year. Birds in this
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study are adult breeders of unknown age and unknown prior breeding experience. One member of the pair
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receives an aluminum flipper band and the other is marked with a stainless steel band such that both band
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types are distributed equally among the sexes. In the following breeding season, adults marked with
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flipper bands the year before are recaptured (visually resighted) in and around the breeding colonies and
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observed to determine breeding status. The presence/absence data, provided in Table A2, were used here
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to estimate return rates among breeding birds banded with different band types.
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On average, 40% of all aluminum bands are resighted the following year, while 50% of all stainless steel
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bands are resighted the following year. For any given year, the return rate of stainless steel bands were
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greater than for aluminum bands by 10.4% (95% CI: 4.3% - 16.4%; Paired t-test: t = 3.76, df=12,
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p=0.002). This difference is largely driven by higher return rates of females with stainless steel bands
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(13.6% greater than aluminum bands, 95% CI 7.4 – 19.9%, paired t-test: t = 4.78, df=12, p=0.0005) than
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males (7.4% greater than aluminum bands 95% CI: 0.0-15.1%, paired t-test t=2.08, df=12, p=0.06).
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The higher return rate of stainless steel bands is consistent with the higher retention rate of stainless steel
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bands estimated in the double banding study. The two data sets reported here support the inclusion of
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band affects in the Capture-Mark-Recapture models for estimating survival rates of Adélie penguins at
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Admiralty Bay.
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References
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Hinke JT, Salwicka K, Trivelpiece SG, Watters GM, Trivelpiece WZ (2007) Divergent responses of
Pygoscelis penguins reveal a common environmental driver. Oecologia 153:845-855
Kendall WL, Converse SJ, Doherty PF Jr., Naughton MG, Anders A, Hines JE, Flint E (2009) Sampling
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design considerations for demographic studies: a case of colonial seabirds. Ecol App 19:55-68
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Trivelpiece WZ, Trivelpiece SG (1990) Courtship period of Adélie, gentoo, and chinstrap penguins. In:
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Davis JS, Darby JT, (eds), Penguin Biology. Academic Press, Inc, San Diego, pp 113-127
Table A1 Release and recapture information for doubly-tagged male Adélie penguins(Pygoscelis adeliae)
at Admiralty Bay, King George Island. All recapture data are made the year following the initial banding
event
Band Type
Alum + PIT
SS + PIT
N. released
100
100
N. recapture (yr+1)
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N. recaptured with both bands
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N. recaptured with only flipper band
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N. recaptured with only PIT tag
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Flipper band retention rate (θf) and 95% CI
0.6 (0.39-0.77)
0.97 (0.79-0.99)
PIT retention rate (θp) and 95% CI
0.87 (0.59-0.97)
0.91 (0.74-0.97)
Table A2 Release and recapture information for breeding male and female Adélie (Pygoscelis adeliae) penguins at Admiralty Bay, King George
Island. All recapture data are made the year following the initial banding event
Male
Female
Alum
Alum
Alum
Steel
Steel
Steel
Alum
Alum
Alum
Steel
Steel
Steel
releases
recaptures
recapture
releases
recaptures
recapture
releases
recaptures
recapture
releases
recaptures
recapture
(yr)
(yr +1)
rate
(yr)
(yr +1)
rate
(yr)
(yr +1)
rate
(yr)
(yr +1)
rate
1998-99
51
21
0.41
48
22
0.46
48
14
0.29
51
13
0.25
1999-00
36
12
0.33
61
27
0.44
64
18
0.28
37
23
0.62
2000-01
42
10
0.24
58
28
0.48
58
12
0.21
42
19
0.45
2001-02
53
22
0.42
50
31
0.62
46
18
0.39
49
31
0.63
2002-03
49
10
0.20
50
14
0.28
50
4
0.08
51
7
0.14
2003-04
48
9
0.19
52
21
0.40
52
9
0.17
47
15
0.32
2004-05
51
23
0.45
47
17
0.36
47
15
0.32
51
20
0.39
2005-06
50
31
0.62
50
39
0.78
51
31
0.61
49
35
0.71
2006-07
44
33
0.75
54
42
0.78
52
28
0.54
45
34
0.76
2007-08
54
42
0.78
46
29
0.63
47
31
0.66
53
36
0.68
2008-09
52
19
0.37
48
27
0.56
48
14
0.29
52
21
0.40
2009-10
48
20
0.42
55
22
0.40
52
19
0.37
45
21
0.47
2010-11
52
31
0.60
51
27
0.53
48
17
0.35
49
25
0.51
Average
48.5
21.8
0.44
51.5
26.6
0.51
51.0
17.7
0.35
47.8
23.1
0.49
(SD)
(5.1)
(10.2)
(0.19)
(4.4)
(7.9)
(0.15)
(5.0)
(8.1)
(0.17)
(4.5)
(8.9)
(0.19)
Year