Sex-specific chick provisioning and kleptoparasitism in the Least Frigatebird, Fregata ariel
Bradley C. Congdon A C and Myriam Preker BA School of Tropical Biology, James Cook University, PO Box 6811, 
Cairns, Qld 4870, Australia.
B 321 Pullenvale Road, Pullenvale, Qld 4069, Australia.
C Corresponding author. Email: brad.congdon@jcu.edu.au
Emu 104(4) 347-351 https://doi.org/10.1071/MU03008
Submitted: 16 March 2003 Accepted: 22 July 2004 Published: 16 December 2004
Abstract
We examined sex-specific patterns of provisioning behaviour and kleptoparasitic host-use in the Least Frigatebird Fregata ariel. We aimed to determine, first, whether sex-specific kleptoparasitism, either at sea, or adjacent to the breeding colony, is an important source of food for chick provisioning and, second, whether observed behaviour is consistent with the expectation that sexual size-dimorphism in resource-poor environments consistently results in sex-specific divergence of foraging behaviour. We observed sex-specific differences in the time of day that adult frigatebirds provision chicks but no differences in the overall provisioning rate between sexes. We also observed no sex-specific kleptoparasitism via simultaneous monitoring of provisioning by Least Frigatebirds and Masked Boobies. Sex-specific differences in prey types attacked at the colony were observed, but these conflicted with predictions based on previous studies and were directly correlated with diural patterns of adult frigatebird attendance. Overall, we suggest that sexual differences in foraging behaviour in Least Frigatebirds are minimal and relate to either the use of different risk-sensitive foraging strategies by each sex, or are a consequence of body size differences in independently foraging sexes. While our results must be considered preliminary, we believe they provide justification for further critical examination of mechanisms of sex-specific behavioural divergence in seabird taxa.
Acknowledgments
Our sincere thanks to the following people and institutions who provided logistic assistance during this project: John Cornelius, Dave Neil, Pam Dyer, the Raine Island Corporation, the crew of the QNPWS research vessel Kerra Lyn, the Queensland National Parks and Wildlife Service (Cairns). This project was funded by a Raine Island Corporation Research Support Grant.
Aho, T. , Kuitunen, M. , Suhonen, J. , Hakkari, T. , and Jantti, A. (1997). Effects of male removal on female foraging behavior in the Eurasian Treecreeper. Behavioral Ecology and Sociobiology 41, 49–53.
| Crossref | GoogleScholarGoogle Scholar |
Megyesi, J. L. , and Griffin, C. R. (1996). Brown Noddy chick predation by Great Frigatebirds in the northwestern Hawaiian Islands. Condor 98, 322–327.
Pasinelli, G. (2000). Sexual dimorphism and foraging niche partitioning in the Middle Spotted Woodpecker Dendrocopos medius. Ibis 142, 635–644.
Peters, W. M. D. , and Grubb, T. C. (1983). An experimental analysis of sex-specifc foraging in the Downy Woodpecker, Picoides pubescens. Ecology 64, 1437–1443.
Vickery, J. A. , and Brooke, M. D. L. (1994). The kleptoparasitic interactions between Great Frigatebirds and Masked Boobies on Henderson Island, South Pacific. Condor 96, 331–340.
Woo, K. , Kober, K. , and Gaston, A. J. (1999). Differences in timing of incubation shifts between male and female Thick-billed Murres are associated with variation in maximum diving depth. Pacific Seabird 26, 55.