Habitat selection and bird community in a mature beech forest

点击翻译按钮获取中文摘要

A study plot of 10ha was set up in a mature beech forest at Kaya-no-daira in north-eastern part of Nagano Prefecture. Birds were captured and color-banded for individual identification. I collected data on breeding performances of birds starting from territory establishment in May to fledging of the latest young in July for three years, with all other kinds of behavioral data including foraging and interactions. As the plot is covered with deep snow during winter, only small portion of breeding bird species (mainly cavity-nesters) winter there. The wintering species, e.g.Parus ater, P.major, Dendrocopos major, Sitta europaea, however, dominated in the breeding community. Two other abundant species (summer visitors) were Ficedula narcissina and Emberiza variabilis. The former is a cavity-nester and the latter is a nester in sasa-bush. The abundant six species formed territories all over the plot, while some other species, e.g.Cettia diphone, E.spodocephala, had territories confined to t … More he forest-edge and canopy gaps, which suggests that canopy gaps supplied edge-dwelling species with breeding habitats within the forest. Some males of the six abundant species formed territories in the plot for more than a year. In these cases, the positions of the territories of a male were almost the same between years, suggesting that individual males could select habitats on the Principle 'settle where you bred before.'The six abundant species were generally segregated vertically in their foraging positions. But this segregation collapsed with snow-melting and foliation in mid-May ; all the species shifted their foraging sites to the foliage and repeatedly attacked leaves of beech. This shift is probably related to the flush of leaf-eating insects at this period, and suggests the existence of an important process determining the bird community structure during the severe, food-poor period before snow-melting. Existence of interspecific competition between cavity-nesters for nest-cavities was also suggested. Less