Aves, p�le ornithologique de Natagora

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Aves, 39/1 | 2002 | 3-21

  Habitat use by the Spotted Nutcracker (Nucifraga c. caryocatactes) in the Norway Spruce (Picea abies) forestry
Schmitz, L.

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Article summary

This study of habitat choice in the Spotted Nutcracker was conducted south-east of Spa (5°57' E; 50°28' N) at a 480-565 m elevation range. A statistical index of even-aged Spruce stands use was assessed by counting empty hazelnut shell remains on 104 hundred m line-transects during a brief period lasting from December 27th 1992 to January 1st 1993. This index peaked in 7 to 15 m mean height and 16 to 30 years old stands, the Nutcracker feeding habitat ranging from 7.2 to 23.7 m and 12 to 58 years resp. A 2 m high pruning is the first cultural operation, occurring shortly before the first thinning at a stand age of ca. 20 years. Pruning significantly reduced habitat use by the Spotted Nutcracker as does thinning a bit later, but less clearly. The method used provides an insight into habitat use by the Nutcrackers for feeding activities ranging from food caching to recovery and consumption. Yet it covers neither hoarding and caching at the hoarding place nor possible intra-seasonal habitat choice variation. The selection of thick-cover stands provides a good protection against snow cover which depth is twice as high in mature stands and four times higher in forest gaps and clearings. It is assumed that this caches are also safe from seed-eating mammals like Red Squirrels (Sciurus vulgaris), Bank Voles (Clethrionomys glareolus) and Wood Mices (Apodemus sylvaticus and flavicollis). The use of close stands may allow the Nutcracker to keep an individualistic behaviour during the whole non-breeding season. Finally, attention is driven to the possible role of habitat choice in the Nutcracker's range evolution in Europe following the conifer forestry expansion and occurring independently of the invasive movements.

Articles on the same species

Cassenoix moucheté européen
Nucifraga caryocatactes caryocatactes

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