Correlates of Creeping Speed Variability in Two Species of Treecreepers

Abstract

Foraging behavior of Short-toed Treecreeper Certhia brachydactyla and Eurasian Treecreeper C. familiaris was examined to test how well it fits a simple foraging model using data on arthropod distribution on tree trunks. Field observations in general supported the model predictions. Short-toed Treecreeper crept, on average, slower than Eurasian Treecreeper. Both species crept more slowly on larger trees. Eurasian Treecreeper crept slower on thick English oaks than on thick Scotch pines. Both treecreepers moved slower when probing as compared to gleaning, which was expected as foraging technique strongly affects handling time.