Foraging behavior of the Eurasian Three-toed Woodpecker subspecies Picoides tridactylus funebris in southern Gansu, China

Abstract

Freiburg, Germany Abstract The Three-toed Woodpecker subspecies Picoides tridactylus funebris is endemic to the Qinghai-Tibet plateau in China. No part of its life history was ever reported since its discovery in 1870. To close this gap, we observed foraging behavior of a pair between April and August 2007. A total of 117 observations (28 for male and 89 for female) were obtained by following the birds within their home-ranges using radio-tracking. P. t. funebris preferred foraging on live spruces and snags bigger than available with an average diameter of breast height (DBH) of 32.7 ± 9.2 cm. The most frequent foraging technique was pecking (39.8% of foraging time) and peeling (13.2%). Moreover, sap-sucking was observed more often in P. t. funebris than in P. t. alpinus , suggesting that P. t. funebris was more dependent on the tree sap than the other subspecies. We found distinct niche partitioning between the sexes with respect to use of three out of four investigated parameters of the foraging substrates. These differences were likely related to sexual dimorphism pronounced by slightly larger bill of the male. We concluded that the subspecies P. t. funebris displayed foraging behavior which was very similar to that of other subspecies of the