Fall 2009: Week 11 in review

Things seemed more "normal" this past week, at least in terms of volume. Diversity slacks off this late in the season, with only a smattering of lingering migrants but more winter-type birds.

We banded an Eastern Phoebe on 25 October, a species we don't band too often. This was also the day we banded what will probably be our last Gray Catbird of the season, and when we caught our first Purple Finch of the fall (below).

It's always a treat to band a colorful adult male Purple Finch (the young males are not red and look like females). If the color difference between Purple Finches and House Finches doesn't tip you off, also notice the lack of brown streaking on the sides of the Purple Finch, and how straight the top of the upper bill is -- it is curved on House Finches (a male shown below). Should you have either species in your hand, House Finches are pretty docile, while Purple Finches are known for their biting!

On 29 October we had a nice surprise. We recaptured a Slate-colored Junco banded here as a young (hatching year) bird on 24 Oct 2007. Winter site fidelity is well-known in juncos, but given the number of them here during fall and winter, and the wide area on campus they occupy, it's not very often that we recapture one from a previous year. Also on 29 October, a Rusty Blackbird sang for me in the banding area. We no longer see many of this declining species (although it was the 10,000th bird banded at RRBO), so even though I didn't catch it, I was happy to see and hear it.

I also don't catch many White-breasted Nuthatches, but this one got snagged investigating a chickadee that was fussing in the net.

On 1 November, we broke our record for the most robins banded in a single fall season. We ended the day at 357. Our fall average is 172, and our previous high number was 354. This is only the fourth fall season that we have broken 300.

Will be winding down the fall banding season this week.

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.

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.

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.

Where's the jet stream?

In my last post, I blamed the poor fall migration on the position of the jet stream. Fall migration is best following the passage of a low pressure system/cold front, with winds from the north or northwest. Weather systems in North America generally travel from west to east across the continent, with their route guided by winds aloft -- the jet stream. Thus, a nice dip in the jet stream somewhere in the western Great Lakes is most likely to bring the right kind of conditions for birds to move into our area.

My friend Mike McDowell posted some graphics and a nice explanation on his blog last week. Go take a look! His four-panel image comes from WeatherImages.org, and is updated at least daily. The direct link to the current jet stream position image is here, and as I write this on Friday afternoon, it looks like this:

At long last, the jet stream is beginning to sag south. Although it isn't in the ideal position (such as the example Mike posted), it should help move birds along.

The California Regional Weather Service has a great web site that has all sorts of jet stream images and forecasts, including loops. Use the North America "latest available" link here for a detailed current map. This link goes to an animated loop of a five-day forecast.

These maps and forecasts should be used in conjunction with radar images. The Wisconsin Society for Ornithology has a tutorial on how to understand radar images and so does New Jersey Audubon.

Here are those handy links again:

• Current jet stream position and three-day forecast, all in one panel.
• Current jet stream, detailed image with isobars.
• Animated loop, five day forecast.
• Menu of many jet stream image options.
• Radar image tutorial (WSO) and NJA.