Behavioral Ecology Advance Access published online on February 24, 2009
Behavioral Ecology, doi:10.1093/beheco/arp024
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Superb fairy-wren males aggregate into hidden leks to solicit extragroup fertilizations before dawn
a Evolutionary Ecology Group, School of Botany and Zoology, Australian National University, Canberra ACT 0200, Australia b Department of Biological and Environmental Science, Division of Ecology and Evolution, P.O. Box 65, University of Helsinki, 00014 Helsinki, Finland c Australian Antarctic Division, Kingston, Tasmania 7050, Australia d School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK e Institute of Experimental Ecology, University of Ulm, 89081 Ulm, Germany
Address correspondence to A. Cockburn. E-mail: andrew.cockburn{at}anu.edu.au.
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Abstract |
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Female superb fairy-wrens Malurus cyaneus initiate extragroup fertilizations by forays to the territory of preferred males, just before sunrise, 2–4 days before egg laying. Over a prolonged breeding season, males advertise their availability to foraying females by singing during the dawn chorus. Here, we show that 1) males commence dawn advertisement at the same time of the year regardless of their quality or status; 2) subordinate males advertise by singing in close proximity to the dominant, or by using the dominant's song perch, despite inevitable punishment; 3) low-quality dominants and their helpers sing from the boundary of their own territory, which increases their proximity to attractive neighboring dominants; 4) each spatial cluster of males use a common dialect of a song that is implicated in extragroup choice, despite the ability of individual males to sing several dialects; and 5) there is leakage of paternity to lower-quality helpers and neighbors as a result of their "satellite" behavior. Collectively, these data suggest that Wagner's hidden lek hypothesis (Wagner RA, 1998. Hidden leks: sexual selection and the clustering of avian territories. In: Parker PG, Burley NT, editors. Avian reproductive tactics: female and male perspectives. Ornithological Monographs No. 49. Allen Press. p. 123–145) can be extended to birds that defend year-round all-purpose territories and that mating induced by parasitic behavior of low-quality satellites can be one explanation for polyandry in birds.
Key words: cooperative breeding, dawn chorus, extrapair copulation, hidden lek, Malurus, polyandry, song dialect.
Received 16 September 2008; revised 28 December 2008; accepted 14 January 2009.