Friday, January 20, 2012

Winter Feeding by the Goldfinch

Goldfinch, Carduelis carduelis
While some of the Irish population of Goldfinch (Carduelis carduelis) migrate in the winter, the majority are present all year round (1). The bulk of C. carduelis diet in the summer and autumn is comprised of seeds of various plants, various thistle species in particular (2). The unavailability of these in the spring and winter has resulted in C. carduelis being a common visitor to bird feeders in suburban gardens. However, as these are not the most reliable of food sources, C. carduelis relies on insects throughout the lean months to feed. At this time of the year it is common to see flocks of C. carduelis alighting on trees throughout the country to feed on insects present among the branches, as is evident in the picture below and above. Behaviour of the bird will change with the sizes of these flocks. Individual birds in larger flocks become less alert and consume up to 20% more food (3). However, travelling time to the nest feeding spot is also increased as is the likely hood of a larger flock attracting predators.
Goldfinch, Carduelis carduelis
References:
  1. Sterry, 2004. Collins Complete Guide to Irish Wildlife
  2. Glück, 1985. Ibis 127 pp. 421-429
  3. Glück, 1987. Ethology 74 pp. 65-79

1 comment:

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