Sunday, November 8, 2009

An amazing white-breasted robin finishes the season

This stunning and unusual American Robin with a white breast was the highlight of our final day of banding for the fall 2009 season today. Our short, final week was not particularly notable; I'll be posting a season summary in a few days. Meanwhile, let's check out this very cool robin!

American Robins with abnormal plumage are not terribly uncommon. There was the funky orange-faced bird I banded a couple of weeks ago. I band robins with one or a few white feathers at least once a season. In October 2007 I banded an adult female in which nearly all the gray feathers had a frosted appearance. I have found photos of quite a few robins that were the "opposite" of our bird, with pale backs but normal breasts (in Minnesota, Saskatchewan, Iowa, Pennsylvania, and Utah). However, I have never encountered or heard of a robin that had a completely white breast with a normal back, wings, and head like the bird we banded today.

Most of the gray plumage on this robin, which was a hatching-year bird (born this year), was normally-colored. It did have a few partially white feathers on each wing. Most of these feathers were short and/or deformed. On the left wing there was one slightly brittle short feather with a bit of white, and one mostly white feather next to it.

On the right wing, one primary was half white, stunted, and growing in this weird direction. About half of the tail feathers were also "messy" looking, due to some brittleness and twisting to them.

The only hint of orange pigment was on a few feathers under each wing.

This condition is usually called "leucism," which is an abnormal reduction in the deposition of pigment in the feathers. Some leucistic birds appear entirely washed out or pale if the reduction of pigment is roughly equal in all feathers (some authors now call this "hypomelanism"). More often, pigment is absent in only some feathers, and this is known as pied leucism, or "partial amelanism." Both the grayish-brown and orange/rust feathers on robins are colored by various types of melanin pigments.

There are a number of causes for this type of plumage abnormality. Some are environmental, including injury, disease, or malnutrition. Others are genetic. In the dozens of pied leucistic birds that I have handled, I have never noted the white or pale feathers being deformed in any way. This tends to make me believe that this robin's problems were genetic in some way. The bird appeared healthy otherwise.

This was the last robin -- the 391st -- of the season, and a pretty cool way to wrap up fall 2009.

Wednesday, November 4, 2009

National exposure in E/The Environmental Magazine

The November/December 2009 issue of E/The Environmental Magazine has an article about brownfield restoration called "Strange Sanctuary: Old Factories Offer New Hope for Wildlife." It focuses on the potential for wildlife habitat in industrial settings, highlighting the Detroit River International Wildlife Refuge and work I have performed there as part of RRBO's partnership with the Refuge. The article also mentions the monitoring I've done on various Ford Motor Company properties, including the sighting of a Gyrfalcon in 2005. The Ford surveys are done as part of my regular inventories of birds throughout the city of Dearborn. Urban ecology is not, generally, very glamorous work. But as I was quoted saying in the article, "I have come to really love this juxtaposition of the hyper-urban with resilient nature.”

Monday, November 2, 2009

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.

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.