Habitat distribution and conservation of land bird populations in northern Norway

About 300 km line transect censuses of breeding land birds were made in northern Norway in 1974–76. The data (1020 pairs in 26 samples) were grouped into seven major habitats: stony ground and oceanic heath (C1), continental dry heath (C2). “′2Calcarius heath”, dry peatland, wet peatland (C5), meagre and average birch forest, and rich birch forest (C7). Bird density ranged from 22 pairs km −2 (C2) to 364 pairs km −2 (C7), but most habitats had 67–96 pairs km −2 . The bird communities are described. Defining the Optimal habitat for a species as the maximum‐density habitat, the 43 species observed were found to comprise three major groups: tundra species (optimal habitat C1), peatland species (C5) and forest species (C7). Species whose central range includes northern Norway had a broader habitat amplitude than those with a southern or a very northern distribution. A new index was devised for the evaluation of the conservational importance of a habitat or a species. From the North European standpoint. C1 is certainly the most important habitat in northern Norway, as C1 supports many species which are rare in other parts of North Europe. However, population trends should also be taken into account when conservational preferences are judged.