Forage niche differentiation of three sympatric woodpecker species in winter

This systematic survey aimed to acquire knowledge about the foraging behavior of the woodpecker in broad-leaved Korean pine forests,and explore the coexisting features of sympatric woodpecker species,by investigating the foraging habitat and behavior characteristics of three woodpecker species. The species were black woodpeckers( Dryocopus martius),three-toed woodpeckers( Picoides tridactylus),and the great spotted woodpecker( Dendrocopos major) that are distributed in Liangshui nature reserve in the northeastern region of China. The survey was conducted from January 5 to 13,2016 and45 east-west direction parallel transects were set in the core area of the reserve,each with a length 1 km and each transect was surveyed two times. Furthermore,25 and 20 transects were surveyed in the morning and afternoon,respectively. Except for the species and sex of the woodpeckers,15 variables of the forage habitat and behavioral characteristics were measured,which were forest type,slope position,dominant tree species,crown