Spatial variation in seabird density at a shallow sea tidal mixing front in the Irish Sea

Abstract

The distributions of Manx shearwater, guillemot, razorbill, fulmar, and kittiwake were examined in relation to sea surface temperature and salinity at the Irish Sea Front in an attempt to understand the manner in which the front is utilized by seabirds. Bird distribution data were collected from 19 crossings of the front along five transects during July 1990. The spatial distributions of the seabirds were analysed by exploratory variography and the application of generalized additive models. The distributions of Manx shearwater, guillemots, and razorbills were associated with the front. A degree of spatial partitioning was also evident that suggested these species were adopting diVerent strategies for the utilization of resources at the front. Comparison with previous studies suggests that the relationship between the seabirds and the Irish Sea Front has been consistent over a period of several years, indicating that the front is a predictable resource for seabirds.