MEPS 411:271-283 (2010)  -  DOI:

Foraging behaviour and habitat use of a  short-ranging seabird, the crested tern

L. J. McLeay1,2,*, B. Page1, S. D. Goldsworthy1,2, D. C. Paton2, C. Teixeira1,3, P. Burch1, T. Ward1,2

1Aquatic Sciences, South Australian Research and Development Institute, PO Box 120, Henley Beach, South Australia 5022, Australia
2The University of Adelaide, School of Earth and Environmental Sciences, Adelaide, South Australia 5005, Australia
3University of New South Wales, School of Mathematics and Statistics, Sydney, New South Wales 2052, Australia

ABSTRACT: We used satellite tracking technology on the crested tern Sterna bergii, a seabird weighing <400 g. GPS units weighing <22 g were deployed on adult terns brooding young chicks. Individuals typically commuted to foraging grounds <40 km from the colony where their travel speeds slowed to ≤10 km h–1, presumably as prey encounter rates increased. Individuals undertook trips up to 4 h 17 min in length and 118 km in distance, and trip duration was positively correlated with the maximum distance and total distance traveled. Foraging behaviour, examined in relation to habitat characteristics (benthic habitat type, depth, sea surface temperature [SST], chlorophyll a [chl a]), was typically associated with warm (19 to 21°C), shallow (<20 m depth) waters that were relatively high in chl a (>0.5 mg m–3). The most well-supported model (generalised linear mixed model) of foraging behaviour indicated a positive relationship between time spent at sea, distance travelled and chl a, suggesting individuals spent relatively more time foraging at greater distances from the colony in zones of higher primary production. The timing and location of crested tern breeding may be linked to the 2-fold increase in primary production near Troubridge Island over the austral summer. Individual differences in the length (distance and duration) of foraging trips may reflect either prior knowledge of where prey aggregations exist, distinctions in individual niche use driven by the types or sizes of prey available, and/or alternate behavioural states (self feeding and provisioning). The restricted foraging range of crested terns while breeding may make them sensitive to competition with fisheries that operate within their foraging range.

KEY WORDS: Bio-logging · Foraging ecology · Seabird · GPS · Habitat partitioning · Sterna bergii

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Cite this article as: McLeay LJ, Page B, Goldsworthy SD, Paton DC, Teixeira C, Burch P, Ward T (2010) Foraging behaviour and habitat use of a  short-ranging seabird, the crested tern. Mar Ecol Prog Ser 411:271-283.

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