Abstract

Over 1,000 Merlin Falco columbarius nest records were analysed following a national survey in Britain in 1993-94. The broad-scale principal habitat, altitude and nest-site were assessed in relation to clutch size, successful brood size and productivity for 13 study areas. The majority of breeding areas (87.5%) were found in five moorland types (dry heather moor, mixed wet-dry heather moor, wet heather moor, grass moor and mixed grass-heather moor). The use of tall conifer plantations for nesting, away from previously documented areas in southwest Scotland, northeast England and Wales, was not widespread. Habitat choice influenced nest-site, with 77% of nests on the ground in heather, 19% in old stick nests in trees and 2% on crags. Productivity for the two years combined varied in relation to the principal habitat at breeding areas, ranging from 1.9 fledged young per pair in wet heather moors and tall conifer plantations to 2.7 on grass moors and mixed grass-heather moors. Productivity also varied significantly across study areas in both survey years. However, overall productivity for Britain, of 2.0 and 2.5 fledged young per pair for 1993 and 1994 respectively, was indicative of a stable or increasing Merlin population.