Population density and breeding ecology of the House Martin Delichon urbica in Pomerania (NW Poland)

Abstract

Studies were carried out in 23 rural sample plots in NW Poland in 1985-1995 (total study area - 5 117 km2, including 635 villages and other settlements). The density of the breeding population in the overall landscape varied between 2.2 and 16.2 nests/km2, and in built-up areas from 207 to 1303 nests/km2. In the first brood, begun in mid-May, the average clutch was 3.99 eggs; 47% of clutches contained 4 eggs, 23% - 3 eggs and 21% - 5 eggs. In the second brood the average clutch was 3.61 eggs. Clutches of 4 and 3 eggs accounted for 49% and 26% respectively of the total number of clutches. 49% of pairs from the first broods were also involved in second ones. Hatching success (number of young hatched compared with the number of eggs laid) was 94.3% in the first brood and 95.8% in the second. Fledging success (number of young fledged compared to the number hatched) was 97.5% and 95.1% respectively and final breeding success (number of fledglings compared to the number of eggs laid) was 91.9% and 91.2%. A statistical pair produced 5.3 young per breeding season.