Saturday, 1 March 2008

Special birds: Three-toed Woodpecker

Three-toed Woodpecker Picoides tridactylus is a smallish woodpecker, between the slightly larger Great Spotted Woodpecker and slightly smaller Middle Spotted Woodpecker in size. This species is unique amongst European woodpeckers (but not globally) in that it only has three toes on each foot whereas its European relatives have four, hence its scientific and vernacular names. Three-toeds appear compact, stocky, large headed, short-necked and blunt tailed. On a perched view they appear rather dark, mainly because of the minimal amount of white on the wings (compare with Dendrocopos woodpeckers). The nominate tridactylus race of this species occurs in the boreal zone, particularly the fairly continuous area from Scandinavia eastwards into the Russian taiga but there are scattered populations in lowland forests in the Baltic States Poland and Belarus. The alpinus race is found to the south, in several rather fragmented populations in areas such as the Alps, the Bavarian Forest, Sumava Mountains, the Carpathians, the Rodope Mountains, the Balkan Range and the Dinaric Alps. It is worth noting that the Carpathian population is geographically isolated from the Alpine one by some 300-350km though the same race occurs in each. Though Poland hosts both races, their breeding ranges do not seem to overlap. The northeastern Polish population of tridactylus at Bialowieza is around 400km from the nearest alpinus birds in the Carpathians in southern Poland.

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