“Yellow” Palm Warblers

Palm Warblers (Dendroica palmarum) have two races — “Western” Palm Warbler (Dendroica palmarum palmarum) and “Eastern” or “Yellow” Palm Warbler (Dendroica palmarum hypochrysea).  The western race is found in Michigan, and The Birds of Michigan reports that the eastern race (which breeds from Quebec to northern New England) is “at best casual” in the state and gives one documented record, a bird banded in Kalamazoo in 1990.  The Rouge River Bird Observatory banded an eastern Palm Warbler on 1 Nov 2003 (which also represents a late date for Palm Warbler at this site).

This bird was a hatching-year (or juvenile) bird, based on the incomplete ossification of the skull.  It had no chestnut on the crown, and a fairly short wing, suggesting that it might be a young female.

Eastern Palm Warblers are very yellow in all plumages, while western birds are duller. The supercilium (eyebrow) is yellow, while in western birds the face is much browner, and the supercilium is buff-colored.  The entire breast and belly are yellow in eastern birds, with no contrast between the belly and the undertail coverts. Western Palm Warblers have buff bellies (which can be washed with yellow in fresh plumage) which always contrast with the brighter yellow undertail coverts.

Craves, J. A.  2003.  “Yellow” Palm Warbler (Dendroica palmarum hypochrysea) banded in Wayne Co. Michigan Birds and Natural History 10:99-100.

More “Yellow” Palm Warblers

Since this record, four more “Yellow” Palm Warblers have been recorded in Dearborn.
Two were sight records. One was along the channelized portion of the Rouge River on 5 Apr 2006, seen by Cathy Carroll; this is the earliest recorded spring arrival date for Palm Warbler in the city. The second was seen on a regular spring bird survey on campus,  29 Apr 2009, by Julie Craves.

Two more “Yellow” Palm Warblers have also been banded. The bird on the right was banded on 6 May 2008.  Note the bright yellow supercilium and the chestnut coloration of the breast streaks, and once again the uniform yellow coloration of the underparts. The shorter wing measurement of this bird could mean it was a female, although the crown patch was quite extensive which is more typical of a male. Thus, to be conservative, we left the bird sex as unknown.

On 9 October 2010, another “Yellow” Palm Warbler was banded (below). This was a hatching-year bird, as determined by the incomplete skull ossification. It had many chestnut-colored feathers in the crown over a broad area, although they were concealed, and a long wing measurement. This indicates the bird was a male. It was as bright or brighter than the 2003 bird, with some of the chest steaks also having a chestnut coloration.

For comparison, here is a typical fall “Western” Palm Warbler, of the form that is typically found migrating through Michigan:

Fall banding: Week #8 in review

We banded all 7 days of week #8 (3-9 Oct), but several days were shortened by having to replace nets destroyed by deer. The deer herd on campus has gotten so large that we had to resort to surrounding the entire banding area in deer fencing several years ago. Due to budgetary constraints, we used relatively inexpensive plastic fencing which requires continual maintenance. Six got in earlier this week when a tree fell on the fence, causing considerable damage over several days.

Nonetheless, we banded 179 new birds of 30 species. Our best day was 5 Oct, when we handled a total of 63 birds. We breached our season high record for Blue Jays, which was set during our first season in 1992 with 19 birds. We're at 22 for the season now. Many banding stations east of us are having a banner year for kinglets, and it looks like we could be on track to break our own records as well, especially with Golden-crowned Kinglets.

This week was also the first strong showing of Hermit Thrushes. The most fecal samples I have obtained over the last three years for our dietary study was 41 from Swainson's, Gray-cheeked, and Hermit Thrushes combined. We're over that total already, with the bulk of Hermit Thrushes yet to come.

Speaking of thrushes, I recaptured a Gray-cheeked Thrush on 7 Oct that I originally banded on 1 Oct. It had a decent amount of fat upon first capture, and weighed 35.2 grams. When I recaptured it, it had piled on the fat and weighed 45.1 grams, an increase of 28% of its original mass in just six days. This is noteworthy, but not unusual for this species here. Gray-cheeked Over 25% of the Gray-cheeked Thrushes we've recaptured gained greater than 20% of their original mass, and about 10% of them gained more than 30%. This is especially interesting given that this species winters in northern South America. They have a long way to go, and it seems unusual for a bird to gain so much weight so early in their migration.

There were two highlight birds this week. First up was a young male Yellow-bellied Sapsucker banded on 4 Oct. This is only the fourth we've banded here since 1992. They are not uncommon here, but usually hang around above net-level.

The other bird was banded today (10 Oct) -- a Palm Warbler of the eastern or "Yellow" race, which nests east of Ottawa and usually migrates east of the Appalachians. We banded one in 2003 and 2008 and have two spring sight records.

Yellow Palm Warblers, in addition to being slightly larger than the western form that typically migrates through Michigan, have very yellow underparts, with little contrast among the throat, belly, and undertails coverts. Overall they are more washed with yellow, including a yellow supercilium.

Western Palm Warblers, especially in fall, are pretty dull. Here is one from earlier this month:

Even in spring plumage, western birds have brownish chest -- you can see how it contrasts with the throat and undertail coverts in this spring bird in Florida (photo by Len Blumin):

Today's bird was a young (hatch-year) bird that was as bright or brighter than the 2003 bird, which had a short wing measurement and no chestnut color in the crown, indicating it may have been a female. Today's bird had many concealed chestnut crown feathers over a large area and a longer wing, making it a male.

I've updated the Palm Warbler page at the RRBO web site with some new photos later in the week. We average about nine Palm Warblers a fall season, and we are a few bird over that total so far this year -- maybe we'll have a few more individuals to show the range of western Palm Warbler plumages in fall.

Fall banding: Weeks 6 & 7 in review

The last two weeks were characterized by some odd weather. Week #6 (19-25 Sep) featured a return to summer, with very warm weather and substantial south winds, not so good for migration. Last week (26 Sep-2 Oct) began with more of the same, and ended up with an ubrupt change to more autumn-like conditions, although wind and rain were involved. Thus, five full and two partial banding days were lost to weather.

For the period, we had 189 birds of 35 species. The wide diversity of warblers typical of mid-September began to give way to the birds of fall: White-throated Sparrows, Hermit Thrushes, more American Robins. Blue Jays are migrating right now, and we've been catching more of them. It's pretty easy to tell a young blue jay from an adult. As in quite a few species, there is a difference in the shape of the outer tail feathers. In young birds, the first set of tail feathers is usually more pointed:

In older birds, these feathers tend to be blunter:

In theory, this can help you age the bird. In practice, if a young bird loses its tail feathers, they will grow back with the adult form. So if a jay has adult-shaped feathers, you need to have at another characteristic to verify the age. The primary coverts (the feathers that cover the bases of the outer flight feathers) and adjacent alula of young jays are dullish blue-gray or brownish-blue:

In adults, they are brighter blue, and usually barred:

These photos aren't the greatest to illustrate this -- in a lot of jays the differences are pretty obvious, while these individuals were not the best examples.

We had nine recaptures of birds we previously banded. The highlight was the Indigo Bunting that turned out to be oldest Indigo Bunting ever reported recaptured by a bander in North America. There were four birds from last year (Downy Woodpecker, Black-capped Chickadee, American Robin, Song Sparrow), and three from 2008 (Hairy Woodpecker, 2 Gray Catbirds), and a Northern Cardinal from 2005.

On Sunday, September 26 we hosted an informal bird program for a Detroit Audubon Society field trip. A nice group showed up, and they got to see a variety of species. Most of the warblers were banded after the group left, unfortunately! Birds banded were: Blue Jay, Black-capped Chickadee, Philadelphia Vireo, Red-eyed Vireo, Swainson’s Thrush, American Robin, Gray Catbird, Nashville Warbler (below), Magnolia Warbler, Cape May Warbler, Blackpoll Warbler, Wilson’s Warbler, Common Yellowthroat, Lincoln’s Sparrow, White-throated Sparrow, Indigo Bunting, Northern Cardinal, and American Goldfinch.

Super senior P. cyanea

One of the most interesting birds banded this season was not an unusual species, but an unusually old bird. Most small songbirds do not make it through their first year -- they have about an 80% mortality rate. If they make it through their youth, many only live 2 or 3 years. Resident birds tend to live longer than migrant birds, and the farther a bird must migrate each year, the more hazards it faces, and the shorter the typical lifespan.

Indigo Buntings nest over much of the eastern U.S., and winter in the West Indies and Central America, and are therefore considered long-distance migrants. This male Indigo Bunting was first banded as a "second year" bird on 23 August 2003. Thus, it was hatched in the summer of 2002. We recaptured it in May 2006 and May 2007 when it was in breeding condition. This many round trips is pretty remarkable itself.

We caught him again this past week, on 29 Sept. Based on the way age calculations of recaptured birds are made, this makes this bird 8 years and 3 months old -- which happens to be a longevity record for this species in North America, according to the longevity records kept by the Bird Banding Lab. The previous record was an 8-year-old bunting in West Virginia -- a record that stood for the last 48 years.

Fall banding: Week #5 in review

This past week things picked up nicely, bringing us what we expect at this point in migration, a nice diversity and good numbers of birds. We missed a day and a half to rain, but banded 183 new birds and handled 31 recaptures, one of which was a Gray Catbird first banded in 2005. There were 37 species, including 15 species of warblers. We are already at or above our fall season average for Black-throated Blue, Blackpoll, Magnolia, and Nashville Warblers, and American Redstart. The most special warbler of the week was this great young male Hooded Warbler. It is the third ever banded for RRBO, and only the second fall record for Dearborn.

We banded two other unusual birds this week. The first was this dark, heavily marked form of the Veery, matching descriptions of the Newfoundland race.

The other surprise was this European Goldfinch. RRBO has done a lot of research on this species. While not a first for Dearborn, it was interesting nonetheless. This individual was not a wild vagrant from Europe, but an escaped or released cage bird.

We banded four species of vireos this week: Warbling, Red-eyed (we're already at our fall average), Philadelphia, and Blue-headed. I think Warbling Vireos look angry, while Philadelphia Vireos, like the one below, look "cute."

Blue-headed Vireos are one of my favorite species. We don't catch a lot of them, and they are just so handsome.


Actually, photographing any vireo is a challenge. They are all fuss and squirm. My general rule is that I only take a few quick shots of any bird I handle. If I can't get a good one, my loss. I don't have a lot of great vireo portraits because they are so uncooperative, most pictures end up like the next two.

We've been getting a lot of great samples for our study of what fruits birds eat in the fall at our site. This is the fourth year I've collected droppings from Catharus thrushes. I often find (in addition to the seeds, pulp, and berry skins I'm looking for) small hard parts of insects. Most often it is sections of millipedes, parts of beetles, and, frequently, ant heads. I guess thrushes aren't particular about the type of Hymenoptera they eat -- this head of an Eastern Yellowjacket (Vespula maculifrons) stared out at me from a sample provided by a Gray-cheeked Thrush.

Dana Wloch, one of my undergraduate research associates, is in charge of identifying and categorizing the samples from all other bird species. This is mostly robins and catbirds, but this week we've gotten samples from Rose-breasted Grosbeak and Red-eyed Vireos. Seems like yellowjackets are on the menu, as this head and a couple legs came from one of the vireos.

I've been asked how birds manage to eat bees and wasps without getting stung. Usually, they wipe the insect on a branch or the ground and get rid of the stinger. A more lengthy answer can be found in my February 2007 column in Birder's World magazine.

And another new bander has joined the team. Welcome to Sara Cole, a senior at Wayne State University. Here is Dana showing Sara how to age and sex her first bird, a Common Grackle.

It was a fun week. More birds coming up.