The use of grey alder Alnus incana by foraging Black Woodpeckers Dryocopus martius during winter
Very few studies have been made on the Black Woodpecker’s Dryocopus martius feeding on deciduous trees in Scandinavia, especially at winter. This pilot study on the Black Woodpecker’s feeding in grey alder Alnus incana showed that the grey alder is a significant feeding tree during the winter months. The woodpeckers seem to prefer feeding in the southerly sector of grey alder trunks with a diameter of 13.5–15.4 centimetres, in their first dying stages. This study indicates that litter of a significant size, that is found beneath trees penetrated by woodpeckers, are from carvings made by the Black Woodpecker. Litter surveying may hence be an alternative investigational method to radio tracking for nutritional studies on the Black Woodpecker. This paper also discusses the role of a potential prey found in grey alders, the alder wood-wasp Xiphydria camelus, as a complementary food source at winter in different parts of Sweden, compared to the more well-described carpenter ants Camponotus herculeanus found in Norway spruce Picea abies.
Copyright (c) 2020 Christer Olsson
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