SCHEKKERMAN H (1989) Autumn migration and biometrics of Lapland Bunting Calcarius lapponicus at Castricum NoordHolland. LIMOSA 62 (1): 29-34.

Lapland Longspur Calcarius lapponicus The autumn migration of the Lapland Bunting in the western part of the Netherlands is described on the basis of birds sighted or trapped at Castricum (Noord-Holland) during the period 1965-86. The first birds were seen in late August and early September, but regular migration occurred from the second half of September till late November, peaking at the end of October (fig. I). Numbers varied strongly from one year to the next, good and bad years showing different seasonal patterns of occurrence (fig. 2, 3). There was no significant difference in median migration dates between males and females, but adults seemed to pass later than first year birds, though only very few adults were caught (tab. I). Of the trapped buntings, 94% were in their first year and 58% were males. Data on wing length, subcutaneous fat, and weight are presented (fig. 4, 5, tab. 2). Mean wing length of males was larger in September and early October than in late autumn. The presence of subcutaneous fat suggested a bimodal pattern in fattening with peaks in the first half of October and in winter. The great majority of birds passing Castricum must be of northern European origin. On the basis of arrival times of Greenlandic Lapland Buntings in the northwestern British Isles (mainly September) and the fact that mean wing length of early birds at Castricum is closer to that of birds caught in Greenland in August than to that of later birds at Castricum, it is suggested that at least some early (mainly September) migrants in the Netherlands may be of Greenlandic origin. In the literature Lapland Buntings are reported to be more numerous in western Europe during autumn migration than in winter. The possibility is therefore suggested that the wintering area extends further into Europe than is presently recognised and lor that birds may winter widespread on the continent in low densities.

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