Wednesday, November 10, 2010

MLNP banding update, early November

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Although the vast majority of landbird migrants have already proceeded south, I am still running the banding station at the Muskegon Lake Nature Preserve on a limited basis in order to better track late-season movements and phenomena. To illustrate: Just in the past couple days, the captures of American Tree Sparrows and American Goldfinches, both still moving thru the station in good numbers, have shifted from adults to immatures. While the more incursive species of finches have yet to appear, others have been common.

House Finches are present all year in Michigan, but many birders do not realize that the species is actually quite migratory. Rather large numbers regularly migrate over the lakeshore dunes each spring and fall. One of my autumn-banded birds was recovered the next spring south of South Bend, Indiana.

Purple Finches are fairly common visitors to the preseve from late September onward. While they may share feeder space with House Finches, I have never noticed the two species flocking together.


Like pipits, longspurs, larks, and Snow Buntings, Pine Siskins can be regularly heard calling overhead each autumn, but they do not typically land at the preserve. This individual (an immature female) was the first-ever capture for the station.

Early in the season, I am likely to recapture a few local breeding birds that were originally banded during a previous year. The rate of such returns declines as migration picks up, but then it increases again as migration slows late in the season. This is further motivation for November banding. This fall, I have captured 18 returns from previous years. A notable record is a male Black-capped Chickadee that I banded on August 28 (opening day) in 2007. Despite making an additional appearance that fall, he was absent in 2008. However, he was recaptured repeatedly in 2009. So far this season, I have captured 98 Black-capped Chickadees, but only two from previous years had returned - until he belatedly showed on November 10.

Because of work duties and time spent at the station, I have put little effort into owl banding this fall, but one nice guest was this male Saw-whet Owl. Like most raptors, males are distinctly smaller than females. Although healthy and spry, this bird weighed only 75.5 grams (about the same as a Brown Thrasher). By contrast, my heaviest female weighed 113.6 grams (roughly equal to a Common Grackle) - this was the same individual that reappeared on the other side of Lake Michigan a few days later.

- Brian Johnson
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