Seabird foraging behaviour indicates prey type

Marine Ecology Progress Series

Silvano Benvenuti¹  Anthony J. Gaston¹  Luigi Dall#146Antonia¹  Kyle Hamish Elliott¹  Gail K. Davoren¹  Kerry Woo¹ 

关键词: Thick-billed murre;    Uria lomvia;    Seabirds as indicators;    Dive shape;    Foraging strategies;    Specialization;   

DOI  :  10.3354/meps07221

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: To investigate how a generalist marine predator modifies its foraging behaviour by prey type, we attached time-depth-temperature recorders to chick-rearing thick-billed murres (n = 204) at Coats Island, Nunavut, Canada from 1999 to 2007. Predators varied their behavior along 3 major ‘axes’: foraging effort, prey depth and prey lifestyle (benthic/pelagic). Dive behaviours for different prey—fish doctor, squid, sandlance, amphipods, snakeblenny, daubed shanny, sandlance and Arctic shanny—were discriminated from one another in a discriminant analysis of dive variables and these prey were therefore considered ‘specialist’ prey items. Specifically, amphipods were captured during V-shaped dives near the colony with a slow bird descent rate, squid were captured during deep V-shaped dives in cold water and fish doctor were captured during a long series of U-shaped dives in relatively warm water far from the colony. Arctic shanny and snakeblenny tended to be taken at moderate distances from the colony, with snakeblenny taken at deeper depths. Daubed shanny captures showed a bimodal distribution, with some taken at shallow depths far from the colony and others at deep depths close to the colony. Dive behaviours for Arctic cod, capelin and sculpin overlapped both with each other and the behaviours for specialist prey items and, therefore, were classified as ‘generalist’ prey items. In general, V-shaped dives preceded deliveries of pelagic prey items and U-shaped dives preceded deliveries of benthic prey items. Our results strongly suggest that generalist marine predators use stereotypic behaviour to forage for prey items, based on previous knowledge about what locations/strategies maximized intake for a given prey type.

【 授权许可】

Unknown