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Feeding, fasting and foraging success during chick rearing in macaroni penguins

Green, J.A.; Boyd, I.L.; Woakes, A.J.; Green, C.J.; Butler, P.J.. 2007 Feeding, fasting and foraging success during chick rearing in macaroni penguins. Marine Ecology Progress Series, 346. 299-312. 10.3354/meps07024

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Abstract/Summary

Foraging behaviour and energy expenditure were measured continuously throughout the chick-rearing period of free-ranging macaroni penguins Eudyptes chrysolophus. These data were integrated with values obtained from the literature on body mass, assimilation efficiency, body reserve consumption and deposition rates, chick growth and energy expenditure and energy content of food in a new type of algorithm to predict (with 95% confidence limits [CL]) foraging success and daily changes in body mass. A successfully breeding pair of macaroni penguins will capture 111.7 kg (95% CL: 79.4 to 158.0 kg) of prey during the chick-rearing period. The crucial phase of the chick rearing period was around the time that chicks crèche, when prey consumption rates more than doubled as the male assisted in foraging and recovered from a long fast. Female macaroni penguins extracted 2.28 (1.60 to 3.26) and males extracted 2.84 (2.02 to 3.99) g of prey from their environment for every minute spent submerged during foraging. Only 15.3 (14.7 to 15.6)% of all prey consumed was fed to chicks. While food capture rates increase in the middle of the breeding season, this may be more a function of greater food availability than a response to demands from their chick. Male and female macaroni penguins have differing breeding strategies with the male showing the characteristics of a capital then income breeder while the female has a strategy that shows characteristics of both capital and income strategies simultaneously. The high synchronicity and precise timing of the macaroni penguin breeding season and timing of the increase in prey capture rates suggest an influx of prey to their foraging area during the middle of the breeding season. A depletion of prey resources in the foraging area used during the breeding season could affect foraging success and have profound effects on the body condition and composition of this species and its ability to raise chicks successfully.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.3354/meps07024
Programmes: BAS Programmes > Global Science in the Antarctic Context (2005-2009) > DISCOVERY 2010 - Integrating Southern Ocean Ecosystems into the Earth System
ISSN: 0171-8630
Additional Keywords: Penguin; Antarctic krill; Foraging; CPUE; Energetics; Diving; Breeding
NORA Subject Terms: Marine Sciences
Zoology
Biology and Microbiology
Ecology and Environment
Date made live: 22 Feb 2011 15:56
URI: http://nora.nerc.ac.uk/id/eprint/11744

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