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Time of day is usually not considered an important factor underlying the structure of forest passerine communities. However, this study shows that the positions exploited in trees by some members of a community change during the day in a cyclic pattern. Coal Tit Pants ater, Crested Tit Parus cristatus and Goldcrest Regulus regulus foraged lower and nearer to the trunk at midday than in the first and last hours of the day. Simultanously, there were diurnal changes in the niche breadth (degree of uniformity in the exploitation of the different parts of the trees). The Coal Tit reached the maximum niche breadth values during the central part of the day, with the minimum being recorded at that time for the Crested Tit and the Goldcrest. On the other hand, Treecreepers Certhia sp. did not show significant diurnal variation. These results, together with the changes in activity levels during the day for each species, suggest that time of day plays an important role in the structure of the community, allowing a more uniform use of the habitat and addressing a new interpretation of the interspeciic relationships inside the community, with competitive relationships not showing the same intensity throughout the day. |
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