BUZZARDS BUTEO-BUTEO AND RAVENS CORVUS-CORAX IN THE UPLANDS OF BRITAIN - LIMITS TO DISTRIBUTION AND ABUNDANCE

The current breeding ranges of Buzzards Buteo buteo and Ravens Corvus corax in Britain are restricted to the west, and both are relies of fo rmer widespread but not necessarily even distributions, Moore (1957) a ttributed the Buzzard's contraction in range to persecution by gamekee pers, his evidence being the complementary nature of the Buzzard's dis tribution with those of gamekeepers in the lowlands and grouse moors i n the uplands; others have attributed the Raven's decline to the same cause, Is Moore correct and, if so, are these species' ranges still li mited by persecution! Here we adopt an approach similar to Moore's, wh ereby we compare the current geographical patterns of abundance of Buz zards and Ravens in the British uplands with that of an index of grous e moor density, Unlike Moore, however, we take into account climate, l and cover, topography and sheep stocking density, as well as grouse mo or distribution, using multiple logistic regression modelling, We show that in the uplands the distribution of grouse moors strongly limits that of Buzzards and Ravens but are unable to conclude that this is a result of persecution because there are several competing hypotheses ( moor management, food and nest-site availability) between which we are unable to distinguish.