Sunday, December 12, 2010

Old Goldie

Since 2002, I have been banding birds in my back yard in Inkster, Wayne County, Michigan where, since we moved here in 1987, a total of 140 species have been recorded in, over, or from the yard. Initially only hummingbirds were banded, but in 2004 I began to band all birds in the yard to study populations and winter site fidelity. In general, in "winter" I band three days a month from October to March, and since the yard is so small, set up only two nets in the back, and two traps in the front. Through 2009, a total of 2201 birds of 30 species has been banded, not too bad for a very urban site, 5 miles northeast of Detroit Metropolitan Airport (the red square on the screen capture from Google Earth below).

A number of interesting species have been banded over the years, including 3 Cooper's Hawks, Sharp-shinned Hawk (1 in 2010), a total of 114 Ruby-throated Hummingbirds (2002-2009), a Red-breasted Nuthatch, 3 Brown Creepers, 5 Carolina Wrens, Ruby-crowned Kinglet, Hermit Thrush, Black-throated Blue Warbler, Field Sparrow, Common Redpoll (2008), and 19 Pine Siskins (1 in 2008, 18 in 2009). But more than half of all birds banded (1200+) have been American Goldfinches. It is interesting to see the population ups and downs over the years, but it is the recaptures that are even more interesting. Over the years, I've caught two different American Goldfinches banded in Dearborn, 5-6 miles away, by Julie Craves. One of the goldfinches I banded in the yard was found in spring near Hamilton, Ontario. Each winter, several goldfinches banded in previous winters return, and birds that are 3-4 years old are not too uncommon.

Last week, however, I caught an adult male goldfinch that I had originally banded as a second-year male on March 9, 2004. This means he was hatched in summer 2003, so was 7 years old this summer. This is by no means the oldest American Goldfinch on record. The Bird Banding Lab maintains a web page of longevity records, where they show the record for American Goldfinch as 10 years, 5 months. The standard way of determining a recaptured bird's age is to presume it was fledged in June. This works well for most songbirds, but late-nesting species like Cedar Waxwings and American Goldfinches may not fledge until July or August (or even early September). But even though he isn't the oldest, it appears he is among the oldest (maybe 7th oldest), and so I've nicknamed him Old Goldie. Oddly, unlike many other goldfinches that are recaptured in the yard, this bird has not been captured even once since he was originally banded in 2004. Maybe he'll change his pattern and return in a couple years.

This isn't Old Goldie, but another winter adult male American Goldfinch.

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