Antipredator Behavior and Breeding Associations of Bar-Tailed Godwits and Whimbrels

Abstract

-Breeding associations between Whimbrels (Numenius phaeopus) and Bar-tailed Godwits (Limosa lapponica) were studied in Finnmark, northern Norway. Bar-tailed Godwit nests were distributed closer than expected by chance to Whimbrel nests. Timing of egg laying showed that the godwit, not the Whimbrel, chose to nest close to the other species. Whimbrels defended their nests aggressively against predators, while Bar-tailed Godwits did not. Godwits nested within the aggressive response distance of nesting Whimbrels. We suggest that Bar-tailed Godwits seek nest protection by breeding under the of the Whimbrel. Received 28 May 1991, accepted 22 February 1992. THERE ARE numerous studies of antipredator behavior in the Charadriiformes (shorebirds and allies). A number of species in this group defend their broods actively against potential predators (Gochfeld 1984). This defense may take the form of physical attacks, and often results in the retreat of the predator. Aggressive antipredator behavior of this kind may benefit more timid species nesting in the neighborhood, and lead to breeding associations in the area defended by the aggressive species (denoted by Dyrcz et al. 1981). Well-known examples are a number of species seeking protection in colonies of terns and gulls (Koskimies 1957, Fuchs 1977, Nuechterlein 1981, Burger 1984), but even the protective umbrella of more solitary species like Lapwings (Vanellus vanellus; Goransson et al. 1975, Elliot 1985), Black-tailed Godwits (Limosa limosa; Lind 1961, Dyrcz et al. 1981), and Merlins (Falco columbarius; Wiklund 1982) is utilized by other