Thursday, March 18, 2010

Black-capped Chickadees

Aldo Leopold in his classic book, A Sand County Almanac, writes of banding Black-capped Chickadees in Wisconsin. Of 97 banded during the 1930s, only one lived to be five years old. He also figured their winter range was about a half mile. Birds dispersed further afield after the winter, with many of his banded chickadees mating with unbanded ones in the spring.

So it is with my chickadees (although I retrapped two of my chickadees banded in Northfield near Dundas, about two miles south of Northfield banding station. Both were banded on 21 August 2008 and recovered on 10 September 2008. One of these birds was subsequently retrapped near Dundas on 21 September, 2 October, and 14 November (all 2008)).

I caught three chickadees this morning in Northfield: to my surprise, two where unbanded. The third was banded locally on 28 October 2009.

Do Black-capped Chickadees migrate? Carol Tveekrem once wrote me that there is a definite southward movement of Black-capped Chickadees along the North Shore of Lake Superior in Minnesota. I am unaware of any banded Minnesota chickadee recovered outside of the state. Chickadees in New England are reported to move into more southern states during very cold winters. Most of our Minnesota winters are considered to be very cold...

The oldest banded chickadees in Minnesota (according to Bird Banding Lab records) are two 9 year-old chickadees. Both were recovered near to their banding locations. The national longevity record for this species, according to the Banding Lab, is 11 years, 2 months (http://www.pwrc.usgs.gov/bbl/homepage/long6882.cfm#Chickadee). (The bird was banded and recovered at the same location in Massachusetts.)

Finally, I am surprised by my chickadee photograph. This species clearly seems to possess binocular vision--undoubtedly helpful for flying through the forest!

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