A Pine Siskin displaying more than the usual amount of yellow
Now that the fall songbird migration is winding down, birders and especially those who feed birds turn their attention to winter finches.
Winter finches are birds that spend most of their lives in the far north, but that for one reason or another appear irregularly during winter in the populated regions of Canada and the northern United States.
These birds occasionally join the usual chickadees, white-breasted nuthatches, titmice, goldfinches, cardinals, woodpeckers, blue jays, starlings, house sparrows and house finches at feeders. Properly identified, the winter finches add excitement to the experience of those who maintain these feeding stations.
It is important to understand at the outset that under the right conditions, these birds are permanent residents, that is they stay all year in the north. It is only when something causes them to retreat that we see them.
Winter finches include ten species. Listed in my estimated order with rarer later, they are: red-breasted nuthatch, pine siskin, purple finch, common redpoll, white-winged crossbill, red crossbill, hoary redpoll, Bohemian waxwing, evening grosbeak and pine grosbeak.
One bird on that list deserves special comment, the evening grosbeak. For years this was a common bird at feeders all across the Northeast, in fact too common for many who were feeding them. A few grosbeaks would go through pecks of sunflower seeds and some feeders were priced out of operation. Those same birders would be happy to have the evening grosbeaks back as the species is now considered threatened. Over the past fifteen years hardly any have been reported locally.
Can we project how many winter finches will appear at feeders? Some serious ornithologists believe that it is possible to do so. They base their predictions on the various seed crops in the far north on which these species subsist. Visitors to the northern forests report on that various trees and shrubs and those reports are then analyzed as individual food crops relate to individual species.
Toronto birder Jean Iron has written recently about what to expect this year: "This winter's theme is that cone crops are excellent and extensive across much of the boreal forest and the Northeast. It will not be a flight year. Finches will be spread thinly over a vast area from western Canada east across the Hudson Bay Lowlands into Quebec and the Atlantic Provinces, New York and New England States. White-winged and red crossbills and pine siskins should be widespread in low numbers. A small movement of pine grosbeaks is probable because mountain-ash berry crops are variable and some are of poor quality in the boreal forest. Evening grosbeak numbers are increasing as spruce budworm outbreaks expand in the boreal forest so some may show up at feeders in southern Ontario and the Northeast. Redpolls are unlikely to come south because the dwarf birch crop is bumper in the Hudson Bay Lowlands."
Notice how in that analysis food source differences have an effect on particular species. At the simplest level, crossbills feed almost exclusively on cones so there can be millions of other seed crops in their home areas with no effect on their numbers.
Here are some of the particular crops and their condition in the north on which Irons reports together with the birds affected by that condition:
Mountain ash (variable): pine grosbeak, Bohemian waxwing. Buckthorn (good): pine grosbeak, Bohemian waxwing. Crabapple (average): pine grosbeak, Bohemian waxwing. Spruces (good): crossbills, pine siskin, red-breasted nuthatch. Birches (excellent): redpolls. Be sure you understand that the better the crop in the north, the less the chance of the related species appearing here.
There are two quite different controlling factors that affect winter finches. The first is an insect on which two species feed: spruce budworm, whose numbers are low but increasing affects purple finch and evening grosbeak. The second factor also affects purple finches. Their numbers have been sharply reduced by competing house finches. As house finch numbers decline due to a widespread eye infection, purple finch numbers should increase.
As usual and despite all those projections, what will count is what appears at feeders. And one early experience suggests that this winter may not be so bad after all. Betsy Brooks reports that her banding station near Rochester caught a flight of 311 pine siskins in one day.-- Gerry Rising