Divergent foraging strategies during incubation of an unusually wide-ranging seabird, the Murphy's petrel ...

• Main Author: Brooke, MDL
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer 2019
• Subjects: activity patterns; area-restricted search; behavioural consistency; biologging; body mass; expectation maximisation binary clustering EMbC algorithm; gadfly petrel; seabirds; Henderson Island; Pacific
• Online Access: https://dx.doi.org/10.17863/cam.35620; https://www.repository.cam.ac.uk/handle/1810/288304

Divergent foraging strategies may emerge within a population due to a combination of physiological and environmental factors, yet in order to persist, neither strategy should offer a consistent selective advantage over the alternative in the long term. Murphy’s petrels Pterodroma ultima from Henderson Island (24°20’S, 128°20’W) in the South Pacific Ocean are highly vagile, and exhibit two distinct foraging trip types during incubation; similar proportions of birds undertake either looping trips around the South Pacific Gyre to waters off Peru (hereafter “East”) or trips south-west of the colony towards the Subtropical Front (“South”) (maximum ranges of c. 3,800 or 2,000 km from the colony, respectively). However, the relative benefits of the distinct trip types remain unclear. Through tracking birds with GPS and salt-water immersion loggers in 2015, the fine-scale foraging behaviour was examined for East (trip durations: 14.1 – 19.8 d, maximum ranges: 2,387 – 4,823 km) and South trips (12.9 – 25.8 d, 1,565 – ...