View article

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 …