Gloger’s ecogeographical rule and colour variation among Willow Tits Parus montanus

摘要: The Willow Tit Parus montanus is distributed across the Palaearctic and into Oriental zoogeographical region with 15 subspecies. P. m. borealis only subspecies in Fennoscandia. Based on 86 skinned museum specimens from Norway (south of 64 oN), we found relatively large variations colours mantle, underpart cheeks. Birds along coast are significantly darker have less white their cheeks than inland birds. Furthermore, birds become paler underparts towards north east, particular annual precipitation explains a significant part colour variation. This accordance Gloger's climatic rule that points out feathers tend to be darkly coloured habitats where relative humidity high pale it low.