Flexibility in foraging strategies of Brown Skuas in response to local and seasonal dietary constraints

Carneiro, Ana P.B.; Manica, Andrea; Trivelpiece, Wayne Z.; Phillips, Richard A.. 2015 Flexibility in foraging strategies of Brown Skuas in response to local and seasonal dietary constraints. Journal of Ornithology, 156 (3). 625-633. https://doi.org/10.1007/s10336-015-1156-y

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Abstract/Summary

The Brown Skua Stercorarius antarcticus lonnbergi is an opportunistic species that displays a high degree of flexibility in foraging tactics. We deployed global positioning system (GPS) and immersion (activity) loggers on breeding Brown Skuas of known sex, body size and condition at Admiralty Bay, King George Island with the aim to examine the impacts of spatial and seasonal fluctuations in prey availability on movement and foraging behavior. We also investigated whether reversed sexual size dimorphism (females larger than males) in this species leads to differences between sexes in foraging behavior and whether this or other factors contribute to variation in breeding success. Analysis of the GPS data highlighted the high degree of plasticity in foraging behavior among individuals. Although most Brown Skuas were flexible in their feeding tactics, this was not enough to ensure a successful breeding season, as few pairs fledged chicks. During early chick rearing, Brown Skuas spent most of their time on land, feeding almost exclusively on penguin chicks. By late chick rearing, when the availability of penguins had diminished, Brown Skuas supplemented the food obtained on land by traveling to the ocean. All foraging trips to sea occurred during daylight, mostly during the early morning. Despite marked sexual size dimorphism, we failed to find any difference in foraging tactics between males and females. Furthermore, although laying date affected the number of chicks hatched (earlier pairs were more successful), no relationship was found between breeding success and male or female body size, condition or degree of dimorphism within pairs

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1007/s10336-015-1156-y
Programmes:	BAS Programmes > BAS Programmes 2015 > Ecosystems
ISSN:	2193-7192
Additional Keywords:	activity patterns, Antarctica, behaviour, GPS tracking, prey availability, reversed size dimorphism
Date made live:	09 Feb 2015 14:09 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/509655

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1007/s10336-015-1156-y

Programmes:

BAS Programmes > BAS Programmes 2015 > Ecosystems

ISSN:

2193-7192

Additional Keywords:

activity patterns, Antarctica, behaviour, GPS tracking, prey availability, reversed size dimorphism

Date made live:

09 Feb 2015 14:09 +0 (UTC)