Friday, October 23, 2009

Fall 2009: Weeks 9 and 10 in review

Things have picked up the last two weeks, although the bulk of the birds have been American Robins. We're up to 295 banded this fall. At this pace, we may break our record of 354. Since we are working on determining what they are eating, this is the first year that I welcome them all!

I banded two interesting robins this week. One only had one leg. It looked like an old injury: the foot was gone, along with half the tarsus (the lower part of the leg). The other half of the tarsus was still attached under the skin, but apparently not by a tendon, as it moved and rotated fairly freely. It was all well-healed, and the bird was a healthy-looking adult.

The other robin had orange, rather than white, facial markings (below, with a normal robin up top for comparison). This picture doesn't quite convey just how bold and orange this bird looked. Although I can't recall ever having banded one quite like this, it's not too unusual to get robins with this orange color in place of buff or white on some of the wing coverts.

As for warblers, we are down to the usual Yellow-rumped Warblers, the occasional Nashville Warbler, and some Orange-crowned Warblers. The duller Orange-crowns, like the one below, look a lot like Tennessee Warblers. Orange-crowned Warblers have longer tails, and yellow undertail coverts.

The bird below is a little brighter. The long-tailed look is quite evident here.

For comparison, a Tennessee Warbler banded earlier in the season, a very yellow individual. Slightly different angle, but note the shorter-tailed look.

I also recaptured a Blackpoll Warbler on 22 October which I had banded 10 days earlier. It was very fat to begin with, and positively rotund upon recapture (it weighed 20.2 grams). This represents a late fall departure date for Dearborn.

Other late dates include a Common Nighthawk in west Dearborn on 20 Oct; four Chimney Swifts over campus on 21 Oct; Northern Rough-winged Swallows near the Rouge River, also on 21 Oct; and a Green Heron on campus on 22 Oct.

We have a week or so to go for fall banding before we wrap things up for the season.

Sunday, October 11, 2009

Fall 2009: Week #8 in review

The brown birds of fall have arrived. Here's our first Winter Wren of the season. This species has a very broad range across the Northern Hemisphere. In England, it known simply as the "Wren." In Germany, it is called "Zaunkoenig," which translates to "King of the Fence." An evocative and accurate description for these little balls of fiesty attitude! We often seem to catch them early in the morning. Extracting from a mist net what amounts to an energetic and slippery ping-pong ball in dawn's dim light is one of banding's challenges.

Another brown bird of fall is the last of the Catharus thrushes to migrate through, the Hermit Thrush. This is my favorite of the thrushes in my study, although I like them all. They can be very common this time of year, although so far they have not reached a peak here by any means.

Our #1 species right now is the American Robin. Early October is the peak of migration for them, and the time when large numbers in wandering flocks are descending on campus. Because migration has been relatively slow this fall, I've been coming in on my days off whenever the weather is okay. The first net run or two in the morning can be loaded with robins. I had to drag my good friend Jim "The Big Bwana" Fowler out of banding retirement earlier this week to help out in case I got swamped with robins.

Dana Wloch is the UM-D student in charge of identifying and compiling all the seeds found in the droppings of robins and species other than Catharus thrushes, so she's pretty happy with all the robins right now.

The other group of brown birds that are abundant this time of year are the sparrows, especially White-throated Sparrows. They have certainly arrived, but not yet in the numbers I expect. The non-brown sparrow that is conspiciously scarce so far is the Dark-eyed Junco. We've only seen a few so far this fall. That should change in the coming week.

Saturday, October 3, 2009

Fall 2009: Week #7 in review

Things picked up this week, although overall the weather was quite uncooperative, with rain or wind cutting down our hours substantially. We began the week with a Detroit Audubon Society field trip, which occurs around this time every year. It's an informal morning of talking about RRBO's research, answering questions, discussing the species that we bring out to show the group after they've been banded and just before they are released. This year there was a nice variety of birds. The photos below were taken by Bill Rapai, of Grosse Pointe Audubon.

Orange-crowned Warbler

Gray-cheeked Thrush. Speaking of which, one was
recaptured twice this week that ended up gaining
a whopping 12.8 grams over 11 days -- that's a
gain of 40% of it's original mass! I have had other
over-achieving Gray-cheeked Thrushes over the years,
including one that gained 16 grams. I don't have an
answer why this particular species would pile on so
much fat at this relatively early stage in their
migration (they winter in northern South America). In
these situations, I usually recapture them more than
once over 10 days or so in which weather doesn't seem
to be a factor in delaying their departure. They are
often recaptured the first time quite fat, and just get
fatter every time I catch them.

I've been training a new bander this season, Guadalupe Cummins. She is an environmental science graduate student here at UM-D, and I'm trying to convince her to work on a project having to do with birds. She began extracting birds and banding them on her own this week.

"Probie" and a goldfinch.

Speaking of student projects, we have now collected over 100 samples of bird droppings from robins and catbirds to examine for seeds (and far fewer from thrushes). Robins are especially productive, although sometimes they don't wait until they are in a bag to provide a donation. I carry little glassine envelopes to collect any errant seedy blobs, so long as I can attribute them to an individual bird. This activity has been the source of a lot of amusement and a variety of suggested names and titles. I'll leave you with the winner.

Julie Craves, the Number One of Number Two.