Seabird foraging behaviour can reflect prey abundance at sea, and is influenced by stress hormone levels, thus providing a potential indicator of at-sea conditions. Using common diving petrels ( Pelecanoides urinatrix, hereafter CDPs), a procellariform that preferentially forages on crustacean zooplankton, we sought to understand how spatially separate colonies responded behaviourally and physiologically to contrasting prey levels with a view to recruiting this species as an environmental indicator. In 2016, incubating CDPs from Tiritiri Matangi (− 36.59S; 174.88E, low levels of preferred prey) and Burgess (− 35.91S; 174.12E, high levels of preferred prey) Islands within the Hauraki Gulf, New Zealand, were tracked using GPS devices. We hypothesised that Tiritiri birds would exhibit greater foraging effort and higher stress hormone levels across the breeding season due to lower levels of available prey. Hidden Markov methods were used to model foraging effort, and prey trophic level (stable isotopes: δ 13 C and δ 15 N) and stress hormone levels (CORT) quantified in plasma samples. During incubation birds were spatially segregated when foraging. Tiritiri birds exerted more effort, chasing higher trophic level prey at larger distances from the colony, and had higher body weight and lower CORT than Burgess birds. However, bird CORT levels responded more to reproductive duties (peaking during chick rearing) as opposed to colony location, i.e. CORT was not consistently higher in Tiritiri birds. Although a snapshot, our findings illustrate the promise of integrating multiple parameters when recruiting seabirds as ocean indicators, resulting in improved resolution of future monitoring programmes based upon them.

中文翻译：

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海鸟作为环境指标：常见潜水海燕（Pelecanoides urinatrix）的觅食行为和生态生理反映了当地规模的猎物可用性差异

海鸟觅食行为可以反映海上猎物的数量，并受应激激素水平的影响，从而提供了海上条件的潜在指标。使用常见的潜水海燕（Pelecanoides urinatrix，以下简称 CDP），一种优先在甲壳类浮游动物上觅食的原虫，我们试图了解空间分离的群体如何在行为和生理上对对比猎物水平做出反应，以期将该物种作为环境指标。2016 年，新西兰 Hauraki 湾内的 Tiritiri Matangi（- 36.59S；174.88E，低水平的首选猎物）和 Burgess（- 35.91S；174.12E，高水平的首选猎物）岛屿的孵化 CDP 使用GPS 设备。我们假设，由于可用猎物水平较低，Tiritiri 鸟类在整个繁殖季节会表现出更大的觅食努力和更高的应激激素水平。隐马尔可夫方法被用来模拟觅食努力，以及血浆样品中量化的猎物营养水平（稳定同位素：δ 13 C 和δ 15 N）和应激激素水平（CORT）。在孵化期间，鸟类在觅食时被空间隔离。Tiritiri 鸟类付出更多努力，在距离群体更远的地方追逐更高营养级的猎物，并且比 Burgess 鸟类具有更高的体重和更低的 CORT。然而，鸟类的 CORT 水平对繁殖职责（在雏鸡饲养期间达到峰值）的反应与群体位置相反，即在 Tiritiri 鸟类中 CORT 并不总是更高。虽然是截图，