Aspects of the ecology of the European woodcock Scolopax rustlcola L

摘要: The trends in the numbers of British breeding woodcock Scolopax rusticola and Continental that visit Britain winter were examined using ringing recoveries bag records. proportion foreign: present S England Wales is appreciably higher than N Scotland. Average annual survival rates for adult foreign- ringed estimated as 58% 54% respectively. Calculations production young woodcock, based on Trust Ornithology nest record cards from data collected NE Derbyshire, suggested too few are produced to compensate current rate mortality among woodcock. Woodcock chick was key factor an analysis 15 years Derbyshire. Overwinter loss density-dependent main regulatory, or k, factor. This important because it means arrival probably increases resident birds. A simulation model Derbyshire used estimate maximum sustainable shooting yield effectiveness bans cold weather. When feeding at night winter, select grass fields preference arable use areas dominated by grass. They between older basis relative availability earthworms other soil invertebrates, particularly leather]ackets, Tipulidae larvae. faithful natal site exhibit lower wintering fidelity. experience winters, when freezing conditions prevent birds feeding, recovery population following severe winters took three-year. Most weather movements within only made migrants. In season, selected shrubby cover, typical edges stands, lowland mixed deciduous woodland. upland area birchwood heather moorland, preferred dense birch thickets although nested more open typically bracken Pteridium aguilinum Calluna vulgaris. both situations, habitats most intensively supported available densities avoided. Clearly, conversion grassland will reduce suitable habitat winter. managed coppice last 50 has contributed decline population, provides ideal fact do not breed SW maybe due increased overwinter mortality, a high density occur there