Population fluctuations of Siskins Carduelis spinus,Common Crossbills Loxia curvirostra, and Citril FinchesCarduelis citrinella in relationship to flowering intensityof spruce Picea abies

Siskin (Carduelis spinus) Science Article 1

abstract

Annual population abundances from 1992 to 2002 of Siskins Carduelis spinus, CommonCrossbills Loxia curvirostra and Citril Finches Carduelis citrinella were studied in relationto flowering intensity of spruce Picea abies.We used point countmethod to study thechanges in abundance of the three species in the Northern Black Forest (southwest Germany).Our results indicated that Siskins and Crossbills showed large fluctuations inabundance that correlated with spruce flowering intensity in the preceding year. In contrast,abundance of Citril Finches did not correlate with spruce flowering intensity. Wesuggest that Citril Finches, due to their high breeding site fidelity, their less expressedexploratory breeding behaviour and their preference for pine seeds, do not react to spruceseed availability by a change in abundance as documented for the other two species.

Marc I. Forschler, Lothar Forschler & Ulrich Dorka, Ornis Fennica 83:91-96. 2006

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