The non‐breeding period is critical for restoration of body condition and self‐maintenance in albatrosses, yet detailed information on diet and distribution during this stage of the annual cycle is lacking for many species. Here, we use stable isotope values of body feathers (δ¹³C, δ¹⁵N) to infer habitat use and trophic level of non‐breeding adult Grey‐headed Albatrosses Thalassarche chrysostoma (n = 194) from South Georgia. Specifically, we: (1) investigate intrinsic drivers (sex, age, previous breeding outcome) of variation in habitat use and trophic level; (2) quantify variation among feathers of the same birds; and (3) examine potential carry‐over effects of habitat use and trophic level during the non‐breeding period on subsequent breeding outcome. In agreement with previous tracking studies, δ¹³C values of individual feathers indicate that non‐breeding Grey‐headed Albatrosses from South Georgia foraged across a range of oceanic habitats, but mostly in subantarctic waters, between the Antarctic Polar Front and Subtropical Front. Sex differences were subtle but statistically significant, and overlap in the core isotopic niche areas was high (62%); however, males exhibited slightly lower δ¹³C and higher δ¹⁵N values than females, indicating that males forage at higher latitudes and at a higher trophic level. Neither age nor previous breeding outcome influenced stable isotope values, and we found no evidence of carry‐over effects of non‐breeding habitat use or trophic level on subsequent breeding outcome. Repeatability among feathers of the same individual was moderate in δ¹³C and low in δ¹⁵N. This cross‐sectional study demonstrates high variability in the foraging and migration strategies of this albatross population.

中文翻译：

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稳定的同位素证明了非繁殖信天翁栖息地利用和营养水平的种内差异

非繁殖期对于信天翁的身体状况的恢复和自我维持至关重要，但是许多物种都缺乏年度周期这一阶段饮食和分布的详细信息。在这里，我们用身体羽毛的稳定同位素值（δ ¹³ C，δ ¹⁵ N）来推断栖息地利用和非繁殖成年灰头信天翁的营养水平Thalassarche chrysostoma（ñ = 194），来自南乔治亚州。具体来说，我们：（1）研究栖息地使用和营养水平变化的内在驱动因素（性别，年龄，以前的繁殖结果）；（2）量化同一只鸟的羽毛之间的变化；（3）研究非繁殖期间栖息地使用和营养水平对后续繁殖结果的潜在影响。与先前的跟踪研究协议，△ ^13个个人羽毛的C值表明，非繁殖灰头信天翁从南乔治亚在一系列的海洋栖息地觅食，但主要是在亚南极水域，南极极锋和副热带阵线之间。性别差异微妙但具有统计学意义，核心同位素利基区域的重叠率很高（62％）；但是，男性的δ值略低¹³ ℃和更高δ ¹⁵比女性的N个值，指示男性觅食在高纬度地区和在较高的营养级。年龄和先前的繁殖结果均未影响稳定的同位素值，而且我们没有发现未繁殖的栖息地使用或营养水平对后续繁殖结果的残留影响的证据。同一个体的羽毛之间重复性δ温和¹³ ℃并在低δ ¹⁵ N.这横断面研究表明在觅食高可变性，这信天翁人口的迁移策略。