Tree species preferences shown by foraging birds in forest plantations in Northern England

Abstract

The feeding behaviour of six species of arboreal passerines was studied in a forestry plantation in Country Durham, UK. The study was undertaken to investigate bird species-tree species relationships for birds in Britain, in comparison with those already reported in North America. The birds were censused using a point-count method and observations on their feeding behaviour, particularly the tree species choice when feeding, were made. The birds showed a marked preference to feed in certain tree species (e.g. European larch Larix decidua and sycamore Acer pseudoplatanus) and tended to avoid other tree species (e.g. beech Fagus sylvatica and western hemlock Tsuga heterophylla). Each species of bird showed a preference for a different combination of tree species, which resulted in habitat partitioning. The extent of niche partitioning was primarily determined by this tree preference, but other factors (position within a tree and height of the feeding bird above ground level) also contributed to the separation of the bird species. Both bird density and the number of bird species were positively correlated with the number of tree species present—a relationship which has important implications for the pattern of planting in forests where attention is given to wildlife and conservation interests.