Population trends of some common trans‐Saharan migrant birds, mostly passerines, were investigated using data from breeding census schemes in five northern European countries during the periods 1976‐89 and 1981‐89. Overall, census data for the 14 species censused in all five countries show about equal numbers of increases and decreases. This is not as expected from the work of Berthold et al. (1986) for birds breeding and on migration in central Europe. Comparison of results between national schemes shows no evidence for overall differences in trends. Correlations in census results between the different schemes, species by species, were mainly positive. For all five countries, there were more positive than negative correlations between year‐to‐year population changes and an appropriate measure of African rainfall.
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John H. Marchant (1992) studied this question.
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