Browne & Mead (2003)
montifringilla different breeding seasons. Three Bramblings were found respectively at places 280 km, 420 km and 580 km apart; one Northern Bullfinch Pyrrhula pyrrhula at places 424 km apart (natal dispersal); two Common Redpolls Carduelis flammea at places 280 km and 550 km apart; one Lesser Redpoll C. cabaret at places 300 km apart (natal dispersal); and one Eurasian Siskin C. spinus at places 120 km apart. On the other hand, some adult Siskins in south Scotland were found in the same breeding area in successive years, despite large fluctuations in cone crops and breeding numbers from year to year (Shaw 1990). In North America, one Pine Siskin Carduelis pinus was found at the same place in different breeding seasons, while two others were found at places 346 km and 1138 km apart (Brewer et al. 2000). Of nine recoveries of Evening Grosbeaks Hesperiphona vespertina in different breeding seasons, two were at the same place, three were within 100 km and four had moved 322-946 km (Brewer et al. 2000). Clearly, long-distance moves from one breeding area to another are not unusual in irruptive finches.
While some individuals remain within the breeding range year-round, but change breeding localities, others winter at lower latitudes, at least in certain years. Typically, as mentioned above, the numbers of birds undertaking migration, and the distances involved, vary greatly from year to year. Huge annual variations in the numbers of migrants are evident at migration watch sites, such as Falsterbo and Ottenby in Sweden, in which the numbers of some irruptive species can vary from nil in some years to many thousands of individuals in other years (Figures 18.5 and 18.6). During 1950-1960, the Eurasian Jay Garrulus glandarius count in seven years at Falsterbo was nil, but in 1955 it reached more than 10 000. Over the same period, Eurasian Siskins Carduelis spinus varied from 4220 to 35 904, Common Redpolls C. flammea from 0 to 489, Eurasian Bullfinches Pyrrhula pyrrhula from 0 to 360, Great
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