Förekomst av unga fjällabbar Stercorarius longicaudus i Lappland under 2009

Abstract

Between 12 and 27 June 2009, 10 immature Long-tailed Skuas Stercorarius longicaudus were recorded in breeding areas in Swedish Lapland. Based on plumage characters, these were aged as 3rd calendar year birds. The fraction of immatures in the total number of aged birds was 4–10%, which seems to be in accordance with maximum abundances of immatures reported in earlier studies. The first immature birds were sighted about two weeks after the arrival of adults. There was no breeding this year, and adults and immatures both departed at the end of June. Prospecting before being recruited into the breeding population may enhance early arrival in later years, which in turn may increase the probability to recruit.