Long-term monitoring of a colony of Black-legged Kittiwakes Rissa tridactyla in Scotland

Abstract

A Black-legged Kittwake Rissa tridactyla colony at Dunbar in East Lothian, Scotland, was monitored between 1990 and 2007 with colony size, productivity, and the body mass of adults and nestlings recorded for the duration of the study. The colony increased in size from 641 nests in 1991 to 1,155 nests in 2007. Productivity varied significantly between years but showed no overall trend for increasing or decreasing productivity over time. Nestling body mass also decreased during the study period and there was increased pre-fledging mortality during the last four years. Adult body mass varied significantly but was not correlated with productivity or with changes in body mass of nestlings. Despite the increasing colony size, the decreasing body mass of nestlings and increasing nestling mortality may suggest that food supply is beginning to have a detrimental effect on the Dunbar colony.