Monday, 24 September 2007

Holes: White-backed Woodpecker

This photo shows an adult male White-backed Woodpecker (lilfordi race) in the Abruzzo mountains, central Italy (Paul Harris). Note the almost perfectly round cavity entrance, which is typical for many species including White-backed. The paleness of the exposed wood in the entrance hole indicates the "newness" of the cavity. Indeed, woodpeckers excavate fresh, new nesting holes every spring, though occasionally an old hole will be re-used, presumably after it has proven to be a success, safe nest site. Used cavities often remain clean, as woodpeckers are hygenic breeders removing the droppings of their chicks as they grow, and thus can be re-used (by the woodpeckers who made it or by secondary cavity breeders). White-backed Woodpeckers rarely re-use a hole. This is probably because their holes often do not survive from one spring to the next as they are invariably made in very rotten trees which decay rapidly and become unstable.

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