Variationer i fåglarnas antal vid en matningsplats i en trädgård i ett förortsområde nära Oslo, Norge, 2000 – 2008

Abstract

The presence of birds visiting a feeding site near a villa in a suburban area to the west of Oslo was observed daily at close range during 2000–2008. The bird assemblage consisted of 17 species. Some species were present throughout the year, whereas others occurred during different seasons. Most species showed a stable occurrence from year to year and was little influenced by climatic factors. When comparing with the bird community in a spruce forest about three kilometres away, only 36% of the forest species occurred regularly at the suburban site, showing a considerable loss of diversity when a forest is changed into a suburban habitat. Abundance was recorded by the time it took the birds to consume one kilo of sunflower seeds. Maximum consumption occurred during summer and minimum during late winter. A general decrease in consumption in all years of study started during autumn followed by another marked decrease at the time of the first snowfall, which obviously acted as a signal for emigration out of the area.