Changes in organ size and nutrient reserves of arctic terns (Sterna paradisaea) breeding near a High Arctic polynya

Figures & data

Figure 1. Location of the study site at Nasaruvaalik Island in Penny Strait, Nunavut (75°49′ N, 96°18′ W), in the Canadian High Arctic (Mallory et al. 2017)

Table 1. Mass (±SD) and percentage change in body tissues in male and female arctic terns during prelaying and chick-rearing

	Male terns			Female terns
Body measure	PL (n = 6)	CR (n = 5)	Change (%)	PL (n = 5)	CR (n = 6)	Change (%)
Body mass (g)	115.2 ± 0.1	104.7 ± 1.3	−9.1	116.9 ± 0.6	107.6 ± 0.3	−8.0
SCBM (g/mm)	1.53 ± 0.01	1.59 ± 0.01	4.0	1.59 ± 0.1	1.58 ± 0.1	−0.4
Lipid (g)	6.6 ± 1.3	10.2 ± 1.7	53.5	7.8 ± 1.7	10.1 ± 3.2	30.4
Protein (g)	16.5 ± 0.8	16.5 ± 0.9	−0.5	17.1 ± 1.5	17.1 ± 1.5	−0.1
Heart (g)	1.19 ± 0.11	1.29 ± 0.09	8.4	1.26 ± 0.17	1.29 ± 0.07	2.4
Gizzard (g)	2.3 ± 0.4	1.2 ± 0.01	−45.1	2.3 ± 0.2	1.5 ± 0.3	−35.0
Liver (g)	4.2 ± 0.8	3.9 ± 0.7	−6.6	4.4 ± 1.1	3.3 ± 1.1	−25.6
Small intestine (mm)	386.0 ± 30.3	343.0 ± 49.7	−10.9	337.4 ± 53.1	347.0 ± 28.5	2.9
Small intestine (g)	1.9 ± 0.6	1.4 ± 0.3	−25.3	1.7 ± 0.4	1.4 ± 0.3	−17.2

Note. PL = prelaying; CR = chick-rearing; SCBM = size-corrected body mass (calculated as [plucked] body mass [g]/head length [mm]).

Figure 2. Changes in arctic tern (Sterna paradisaea) body mass (size-corrected dry mass) and associated organ sizes (lipid, protein, gizzard, liver, small intestine) through prelaying (P), early incubation (E), late incubation (L), and chick-rearing (C) on Nasaruvaalik Island, Nunavut, Canada, in 2007. Black circles are females (n = 5, 5, 5, 6) and gray circles are males (n = 6, 4, 4, 5). Circles represent mean values and vertical lines represent the 95 percent confidence interval

Figure 3. Zooplankton from one regurgitation of an arctic tern captured during the breeding season at Nasaruvaalik Island. Photo by Mark Mallory

Mallory, M. L., K. A. Boadway, S. E. Davis, M. Maftei, and A. W. Diamond. 2017. Breeding biology of Arctic terns (Sterna paradisaea) in the Canadian High Arctic. Polar Biology 40 (8):1515–25. doi:https://doi.org/10.1007/s00300-016-2072-1.

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