Monday, January 10, 2011

“Irrupt” Common and Hoary Redpolls and other Winter Finches

Common Redpoll (Credit: All About Birds)
The Common Redpoll, Carduelis flammea, is a member of the family Fringillidae. Fringillidae contains only finch species. Common Redpolls are small winter finches with tiny yellow bills that are found in open willow and birch thickets and weedy fields. This species can be identified by the bright red forehead and black chin. The male has a pink breast, while the female lacks this characteristic. Juveniles lack the red forehead and are heavily streaked, thus making them more difficult to identify. Common Redpolls breed in northern Canadian Territories and are usually found in flocks in birch thickets and at feeders.

Hoary Redpoll (Credit: All About Birds)
Hoary Redpolls, Carduelis hornemanni, is also a member of the finch family Fringillidae. This species can be distinguished from the Common Redpoll by having a whiter rump and containing minimal or no streaking. Also, Hoary Redpolls have a “frostier” look and have a stubbier bill than the Common Redpoll. Hoary Redpolls can be found mixed in with flocks of Common Redpolls and can be hard to identify. Similarly, the Hoary Redpoll breeds in northern Canadian Territories in birch habitat.

Common Redpolls “irrupt” into southern Canada and northern United States when the birch seed crop crashes. Irruptions usually occur every two years. This winter was forecasted to be an “irruption” year for Common Redpolls in Ron Pittaway’s Winter Finch Forecast 2010-2011 that was released in September 2010. Pittaway predicted that Redpolls should irrupt into southern Canada and northern United States this winter. He noted that Common Redpolls are a birch seed specialist in the winter and irrupt into southern Canada and northern United States when the size of the birch crop is very low.

Over the past week I have observed numerous reports of Common Redpolls in flocks of 30 – 50 individuals throughout the northeast United States with only a few individual Hoary Redpolls reported in a few flocks. Because I am from Pennsylvania, I watch reports every day to track Common Redpolls as they make their way down to Pennsylvania. In Pennsylvania, flocks are being seen in the northwestern part of the state. A recent report tallied a flock containing 30 Common Redpolls foraging in birches on Presque Isle State Park! Because Redpolls are foraging in stands of birch trees, the birch crop will soon diminish and the birds will then take to feeders.

Feeders that contain nyjer feed, which is a type of thistle seed, are most likely to be targeted by Common and Hoary Redpolls as well as other winter finches. Refillable thistle feeders are a commonly used feeder to attract winter finches, especially when the birch crop has depleted.

In addition to Redpolls, other winter finches, such as Pine Siskin, Carduelis pinus, and Purple Finch, Carpodacus purpureus, have “irrupted” into northern North America and southern Canada. I have seen flocks of up to 20 Purple Finches in late Fall 2010. A report of 30 Pine Siskins was reported in northern Pennsylvania earlier this month as well. Reports of Pine Siskins continue at feeders throughout the State College and Centre County areas. On another note, Red-breasted Nuthatches are making appearances at feeders throughout the area as well. Recently, Purple Finches seem to have disappeared in the area as I have not observed any or have seen any reports since late fall of 2010.

In Conclusion, certain species of winter finches such as Common and Hoary Redpoll, Pine Siskin, and Purple Finch are having an “irruption” year into southern Canada and northern United States. Observe feeders over the next couple of weeks and search for Common Redpolls and if you are lucky you may be able to pick a Hoary Redpoll out of the flock!

The Sibley Guide to Bird Life & Behavior by David Allen Sibley
The Sibley Guide to Birds by David Allen Sibley
Peterson Field Guide to Birds of Eastern and Central North America by Roger Tory Peterson

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