Adult survival of Arctic terns in the Canadian High Arctic

Figures & data

Figure 1. Location of the Nasaruvaalik Island study site in the Canadian High Arctic.

Table 1. Summary of annual banding and recaptures of breeding Arctic terns at Nasaruvaalik Island, Nunavut, Canada, 2007–2016. New bandings in 2016 are not reported because they occurred in the final occasion of the study and did not inform estimates of apparent survival (φ) and recapture (p).

Year	Number of newly banded terns	Number of terns recaptured	Number of terns subsequently recaptured in future years
2007	59		22
2008	29	6	7
2009	49	1	23
2010	186	12	38
2011	87	25	24
2012	169	59	28
2016		39

Table 2. Summary of goodness-of-fit testing for encounters of banded breeding Arctic terns at Nasaruvaalik Island, Nunavut, Canada, 2007–2016. Test results are from UCARE 2.3.4 (Choquet et al. 2009). The overall test for the global model (Cormack-Jolly-Seber, or annual variation in apparent survival φ_t and recapture p_t) is the sum of all four tests, while the test allowing for apparent survival to differ for individuals newly marked (φ_t/t), is the sum of all tests excluding Test 3.SR. $\hat{c}$ is calculated as χ²/df.

Test	χ^2	df	p value	$\hat{c}$
3.SR	11.31	5	0.046
3.SM	5.74	3	0.124
2.CT	4.01	4	0.406
2.CL	9.68	3	0.022
Global model (φt pt)	30.75	15	0.009	2.05
Model (φt/t pt)	19.43	10	0.011	1.94

Table 3. Model selection results for Arctic terns breeding at Nasaruvaalik Island, Nunavut, Canada, 2007–2016. The survival rate (φ) and the recapture rate (p) subscripted with time (t) indicate that the rates were allowed to vary annually, while (t/t or ./.) indicates that survival rates were estimated separately for the year after first capture compared to survival in future. In all models, recaptures rates for 2013 to 2015 were fixed to 0. Model fitting results were adjusted for overdispersion ($\hat{c}$ = 1.94). QDeviance is an index of model fit, while QAICc is a measure of the model’s ability to explain the data. ΔQAICc is simply the QAICc difference between the best (lowest AICc) model and the model in question, while the QAICc weight is the relative support of each model compared to all others in the model set.

Model	Number of parameters	QDeviance	QAICc	ΔQAICc	QAICc weight
φt/. pt	13	29.58	485.66	0.00	0.652
φ./. pt	8	43.15	488.90	3.24	0.129
φ pt	7	46.56	490.27	4.60	0.065
φt pt	11	39.41	491.34	5.68	0.038
φt/t pt	16	29.41	491.77	6.11	0.031
φ./t pt	12	37.83	491.84	6.18	0.030
φt/. p	8	47.00	492.76	7.09	0.019
φ./. p	3	57.20	492.78	7.11	0.018
φ p	2	59.96	493.52	7.86	0.013
φt/t p	12	41.90	495.91	10.25	0.004
φt p	7	55.42	499.13	13.46	0.001

Choquet R., Lebreton J.D., Gimenez O., Reboulet A.M. & Pradel R. 2009. U-CARE: utilities for performing goodness of fit tests and manipulating capture–recapture data. Ecography 32, 1071–1074.

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