| Summary: | Blakers et al 1984). and is generally associated with waterways in woodlands and open forest (Morris 1976). This eagle is a diurnal predator which hunts visually and rabbits are its preferred food item (Blakers et aL 1984). Storr & Johnstone (1988) reported that the Little Eagle is a casual visitor to Penguin Island, which supports the largest breeding colony of Silver Gulls L a m novaehollan-diae in Western Australia (4000-5000 pairs). These gulls exhibit bimodal egg laying with peaks in late April and August (Wooller & Dunlop 1979). Predation is common in seabird colonies. Colonial nesting in the Black-headed Gull L ridibundus is thought to have evolved as an anti-predator adaptation (Tinbergen 19671, and should facilitate early detection and mobbing of the predator. The protection afforded by large numbers, however, apparently provides limited benefit to those pairs nesting on the periphery of the colony (Patterson 1965), which may be more apt to be taken by a predator. This paper documents the predatory behaviour and success of Little Eagles hunting Silver Gulls on Penguin Island during 1988 and assesses their possible impact on the reproductive success of the gulls. Study site and methods This study was conducted from March to October 1988 on
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