Data in Brief: Twig selection on mountain birch Betula pubescens by winter-feeding willow grouse Lagopus lagopus in a subarctic forest
In a subarctic forest at Kvaløya, northern Norway willow grouse ( Lagopus lagopus ) fed at snow level by clipping bits of twigs from mountain birch ( Betula pubescens ) during winter. Birch has two types of twigs ending in a terminal bud: long twigs with a smooth bark, and short twigs with rings of...
| Main Authors: | , |
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| Format: | Other/Unknown Material |
| Language: | unknown |
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Zenodo
2023
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| Subjects: | |
| Online Access: | https://doi.org/10.5061/dryad.s7h44j1bd |
| Summary: | In a subarctic forest at Kvaløya, northern Norway willow grouse ( Lagopus lagopus ) fed at snow level by clipping bits of twigs from mountain birch ( Betula pubescens ) during winter. Birch has two types of twigs ending in a terminal bud: long twigs with a smooth bark, and short twigs with rings of thicker bark. The grouse selected ringed twigs above smooth twigs despite a surplus of smooth twigs in the forest. Ringed twigs had more bark cm -1 of twig length and a higher relative bark/wood ratio than smooth twigs. Smooth twigs had growth nodes that increased in diameter inwards from the tip. Because of the non-linear relation between the area and the circumference of a circle, the bark/wood ratio decreased for each node. Although being able to clip much thicker twigs, 90 % of smooth twigs clipped by grouse were ≤ 2 mm in diameter. It is concluded that willow grouse fed optimally on birch in winter by selecting twigs to minimize fibrous wood intake. |
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