Wednesday, December 2, 2009

Falcon Nasal Baffles


A structure almost unique to the falcons is a baffle in each nostril.  Conventional wisdom is that these baffles regulate airflow, which would be handy if you were diving at speeds up to 200 mph or so.  Other hypothesis, however, include that the baffles measure air speed or in some way help with the sense of smell.  Curiously hawks, which also dive, lack these baffles.

A baffle can be easily seen in this young Peregrine Falcon, which was recovered in Canon Falls, Minnesota in July 2009 and was transported to the Minnesota Raptor Center.  Unfortunately, this bird did not survive. (It had fledged from the Wells Fargo building in Bloomington, MN.)

Tuesday, November 17, 2009

Races of White-crowned Sparrow




Z. l. leucophrys
 
 Z. l. gambelii
Look carefully the next time you see a White-crowned Sparrow, Zonotrichia leucophrys.  Four races (= subspecies) are currently recognized by the American Ornithologists' Union.  Two can be found in Minnesota--see photos above.  They can be told apart by the lore color (between their eyes and bills) and perhaps by bill color. These races are shown in Sibley, but the illustrations are not labeled scientifically.   The National Geographic guide (third edition) does a better job

The range information quoted below is from Chilton, G., M. C. Baker, C. D. Barrentine and M. A. Cunningham. 1995. White-crowned Sparrow (Zonotrichia leucophrys), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu.bnaproxy.birds.cornell.edu/bna/species/183

Birds with black lores,  Z. l. leucophrys, breed "in north tier east of Hudson Bay, in Rocky Mountain ranges from s.-cen. Canada south through n. New Mexico, in various Intermountain Ranges south to cen. Nevada and s. Utah, and in Cascade-Sierra Nevada axis south to s. California; winters in lowlands across southern tier of United States, generally rarer westward." Their bills are pink. (The photo above was taken near Dundas, MN.)

Birds with gray lores, Z. l. gambelii, breed "across northern tier from Alaska to Hudson Bay; winters south through cen. Mexico, generally rarer eastward." Their bills are orange or pinkish orange.  In the Hudson Bay region, birds intermediate between these two races can be found (although I have never seen an intermediate bird). (The photo above was taken in Aberdeen, SD.)

The other two races of White-crowned Sparrow are found along the Pacific coast from British Columbia south--Z. l. pugetensis is the most widespread (the slightly larger Z. l. nuttalli is found south of Los Angeles).  Both of these coastal races are unlikely to be found inland, even in winter.  I took the photo below at Morro Bay, California.  Note the brownish back and underparts, dusky white head stripes, and yellow bill.

 
Z. l. pugetensis

Tuesday, November 10, 2009

First Year Downy Woodpecker

If you ever get a chance to closely observe Downy (and other) Woodpeckers closely, note their primary coverts. These are the feathers that cover the outer flight feathers.  Notice in these photographs that these feathers are not as jet-black as either the flight feathers or the other feathers near them. This dullness of color indicates a bird born in the immediate past breeding season. The reason for this color differences is that North American Woodpeckers retain their juvenile primary coverts even after they molt their other wing feathers.

Thursday, November 5, 2009

Pileated Woodpecker 1, Bander 1



Score one for the bird--my banding notebook was covered with my blood after the woodpecker finished with me.  Score one for me, this Pileated Woodpecker is only the second of my banding career.  This species is fairly common in Minnesota but was not found where we lived in South Dakota. Notice that the bird closes her eye as she pounds my finger. 

Mike Hendrickson of Duluth recently commented that this fall has been relatively slow for birders state-wide.  I am sorry to report that I agree with his assessment, at least as banding has fared here in the east-central part of the state.

The few animated .gif files like the one above are made at the website: http://www.gifninja.com/  

Thursday, October 22, 2009

Favorite Bird


I am sometimes asked what is my favorite bird.  Erika says my favorite bird is the last one I've seen.  I maintain my favorite is the Common Loon.  I love their long dives, their ability to slowly submerge like a submarine, and, of course, their yodels and cries echoing across the northern wilderness.

Tuesday, October 20, 2009

Black-throated Blue Warbler



I banded and released this Black-throated Blue Warbler on 20 October 2009 in Northfield, Rice Co., Minnesota.  One of the joys of banding birds is encountering uncommon species.  This warbler breeds  in Minnesota only in the far northeast and is an uncommon to rare migrant elsewhere in the state.

Monday, October 19, 2009

Hermit Thrushes



I have been banding many Hermit Thrushes this fall.  If you look at fall thrushes, especially Hermit Thrushes, carefully, you will notice that they often have spotted secondary coverts.  These are unmolted juvenile feathers, indicating that you have a bird hatched this calendar year. (Birds without secondary spots are not necessarily adults, however, since the spots eventually wear away.)

Saturday, October 17, 2009

How does one find joy in common birds?

Al Schirmacher of Princeton, MN, asked the MN-listserv, "How does one find joy in common birds?"
Digital photography has revolutionized my birding.  Today I caught only my second crow, which I banded and photographed--a common bird but not so common in the bird net.  This  bird was with about six others drinking at our backyard water feature. (Note the dull alula feather--an indication that this bird was hatched this year.)

Now I am just as likely to chase after a good bird photo as an unusual bird report.  One day in South Dakota I went out in search of displaying Red-winged Blackbirds.  Imagine my surprise when I found this odd Red-wing!
It also proved hard to find a decent House Sparrow photo.  I spent the greater part of a day in search of this photo:

Friday, October 16, 2009

Oystercatcher Eye Flecks

Erika and I came eye-to-eye with a Black Oystercatcher in January 2008 near Morro Bay, California. I was amazed at the odd shape of the bird's pupil. It turns out that the odd shape is caused by black pigment on the oystercatcher's iris. Furthermore, this mark can be used to tell the oystercatcher's sex. For more information see: Secrets in the eyes of Black Oystercatchers: a new sexing technique. Brian M. Guzzetti, Sandra L. Talbot, David F. Tessler, Verena A. Gill and Edward C. Murphy Journal of Field Ornithology Volume 79 Issue 2, Pages 215 - 223 Published Online: 3 Jun 2008.

We came across an American Oystercatcher in September 2009 at Martha's Vineyard. It also has an iris fleck. Note the bands on this bird. We submitted this photo to the Bird Banding Office but have not heard where the bird was banded.


Cedar Waxwing with Tricolored Tail

Erika and I banded 22 Cedar Waxwings all caught at the same time in Northfield today, 13 October 2009. One was interesting: it had a tricolored tail! Its right outer tail feather tip was white. The central feathers where yellow-tipped. the left two outer feathers were orange-tipped.

I have read about orange-tipped waxwing feathers before. See, for example: http://elibrary.unm.edu/sora/JFO/v063n02/p0212-p0216.html This paper suggests that the cause of orange-tipped feathers may be from honeysuckle that contains rhodoxanthin. "The ripe red berries of these shrubs are available from June through July. Nestling waxwings, which develop rectrices at this time, may be fed honeysuckle berries and consequently grow orange-tipped tails. Adults do not normally molt rectrices until the berries are no longer available, and nearly always have yellow-tipped tails. Several immature birds with orange tail bands were found growing yellow-tipped replacement tail feathers in September and October, after the honeysuckle fruiting period; two yellow-tipped birds were growing orange-tipped replacement feathers in July, when honeysuckle berries were available."