Tuesday, February 10, 2009

A winter of finches

Every so often, a long cold winter is made worthwhile when we get visitors from the boreal north. I'm talking about "winter finches." A number of species move south when their preferred food source becomes scarce in the northern parts of their range. These birds all have a few favorite tree seed species, and trees tend to produce seeds in cycles (up for one or more years, down for another one or a few). This helps us predict when we might see certain winter finches, and in what numbers. The folks in Ontario create an excellent, detailed winter finch forecast every fall. I encourage you to read a recent copy to get a feel for which bird and tree species are involved.

This winter has been terrific for winter finches. The most impressive and special has been the push of White-winged Crossbills. While they are found nesting in Michigan's Upper Peninsula, they are very rare in southern lower Michigan; Dearborn had only a handful of records before this winter. This year, they've been found in nearly every county and in big numbers. It's unlikely an event like this will ever occur again in my lifetime. I've had big flocks in my neighborhood, even my yard, but a reliable group has been working the Douglas firs at a local office building (White-winged Crossbills specialize in soft cones like spruces, hemlocks, and some firs). Here is a male (above) and female (below) taken there by Mike O'Leary.

Pine Siskins were some of the first finches to arrive in early winter and have stayed around in large numbers -- they are often present at feeders. While a couple individuals are found every year, we have not had this type of invasion here in Dearborn since the late 1970s. Pine Siskins will sometimes nest in southern areas after a big invasion year, so I will not be surprised to hear of some breeding in southeast Michigan this summer. We have had only a handful of siskins at any one time here on campus, but scores of them at our feeders at home a few miles away. So far, we've banded over 60 the last couple of weekends. Some are dull, but some are quite beautiful when you get to take a look in the hand.

Common Redpolls have also been very abundant. On campus, they have been busy extracting the tiny seeds out of the small cones on the black alders around Fairlane Lake. Few have come to the feeders. At home, we've had only a few at our feeders as well. Here are a couple of males -- young males and females tend to have little or no pink on the breast.

Last but not least is Purple Finch. We usually see a few Purple Finches every fall during migration. This fall was no exception, but we have heard few reports of many Purple Finches in the area in the subsequent months. It seems like they passed by, went somewhere else, or didn't make it this far south in any numbers. This is the only one I've seen, a male at my feeder. That's a male House Finch below it. Notice the distinct curve to the upper bill of the House Finch. It's quite straight in a Purple Finch, and a good structural clue to telling the two species apart. Here is a guide to identification.

I admit, I loathe winter. But knowing I could easily find and observe these special species has made going out not only bearable, but actually a lot of fun.

1 comment:

Anonymous said...

I had about fifty common red polls at my feeders and/or beneath them on 03/07/09. They tend to be more readily frightened by nearby activity. Usually about one dozen have been seen fairly regularly on a daily basis this winter. They tend to come in mid morning and in greater numbers in the late afternoon. One male white-winged crossbill appeared 03/04/09 and others may have been observed occasionally by family members on several previous days in February. The large numbers of pine siskins that occurred in January has lessened, but they are still visiting thistle feeders on a daily basis.