Jellyfish and fishery waste as food sources of Northern Fulmars Fulmarus glacialis feeding around St Kilda
Sula , Volume 10 - Issue 4 p. 143- 150
Northern Fulmar Fulmarus glacialis diets vary considerably between colonies. The catholic feeding habits of this species implicate that few samples are large enough to fully appreciate the range of prey taken (Furness & Todd 1984, Camphuysen 1990). Zooplankton forms significant food in some populations (Brown 1970, Bradstreet 1978, Camphuysen & Van Franeker 1988), fatty fish like sandeels, capelin or clupeids in others (Fowler & Dye 1987). However, the scavenging habits of Fulmars at fishing vessels have widely been used to explain its population increase and range expansion during the last two centuries (Lockley & Marchant 1951, Fisher 1952, Hudson & Furness 1988, Camphuysen 1990, Camphuysen et al. 1995). This would infer this latter food source to be of prime importance over a wide range. For centuries, St Kilda has been an important breeding station of Fulmars (Figure 1; Fisher 1952). Furness & Todd (1984) were the first to describe and quantify the diet of Fulmars in these remote islands and to compare the food choice of these birds with that on Foula (Shetland Isles). With a substantial variation in diet between colonies, obviously a reflection of local food sources, it can be envisaged that food choice may also vary within a given colony between seasons. In August 1982, Fulmars were captured, ringed and released on St Kilda as part of a morphological study of this species (Van Franeker 1983). Some birds regurgitated the contents of their proventriculus during handling and this article reports on the prey items found in these samples. Although the sample size is small, the data contribute to our knowledge of the food choice of Fulmars on St Kilda and add to the data collected one year earlier by Furness & Todd (1984).
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