Thursday, December 20, 2007

Winter finch arrivals

Each winter brings a new mix of birds to the feeders outside our windows. A flock of 100+ Common Redpolls, accompanied by Pine Siskins and Common Goldfinches, ate nearly 50 kg of niger seed during the winter of 2005-2006. Last year, we didn't see a single Common Redpoll or Evening Grosbeak. This year is another story altogether.

Evening Grosbeaks first appeared in September and have stayed. Presently, we have two or three flocks totaling about 50 birds.
Common Redpolls now festoon the niger silo and the snow beneath. A few of the paler Redpolls may indeed be Hoary Redpolls but there seem to be intermediately coloured birds as well. Some day soon I will step up to meet Jean Iron's Redpoll Challenge, which involves learning to recognize the four redpoll subspecies presently wintering in Ontario.

This year-to-year variation makes backyard birding all the more interesting. To some, these movements may seem erratic but they're not. The so-called "irruptions" of northern bird species are caused by failures of staple food crops in the boreal forest and beyond. Ron Pittaway has acquired some expertise in predicting the movements of "northern birds". His 2007-2008 Winter Finch Forecast is spot-on.