Northern Saw-whet Owl 2

J.H. and I returned to the saw-whet owl location near Faribault this afternoon and found it perched on exactly the same tree, same branch as last week.  This time the owl opened its eyes and glared at us, before going back to sleep.  By the looks of the owl, it appears last night was good hunting.

Scott Weidensaul, in his book "Of a Feather: A Brief History of American Birding," suggests that recent efforts at banding saw-whet owls across the continent indicate that this hard-to-locate species may be the most common of the North American raptors.  His book, by the way, is enjoyable and educational.

Orchids

Erika and I went to the University of Minnesota Landscape Arboretum near Victoria yesterday and enjoyed their current orchid show.  More orchid photos can be seen at http://picasaweb.google.com/danerika/Orchids . These photos are inspired by the goldfinch photos I showed you on a recent post.  This time I used a white sheet of typing paper as background.  Here in Minneapolis/St. Paul region, the Landscape Arboretum is one of our favorite places to bird and botonize.

Northern Saw-whet Owl

Recently I asked my friend Dave Bartkey if he could show me a Northern Saw-whet Owl in Rice Co.  Dave has a remarkable ability to find owls, especially on Christmas Bird Counts. He replied that we could give it a try, but there were no guarantees.  To make a long story short, we walked right by this saw-whet owl at the River Bend Nature Center in Faribault.  On our way out, Dave spied our bird, apparently sound asleep in a isolated cedar.

Northern Saw-whet Owls have always been a favorite bird for me.  When I began banding in Aberdeen, South Dakota, this owl was considered to be quite rare in the area.  But every October I banded about a dozen of them in a residential backyard.  I did not lure them in; they must have been abundant.  I caught most of my birds just before dawn.  Interestingly, I have tired unsuccessfully to band saw-whet owls since I moved to Northfield.

Bird Lists

I keep lists of the birds I have seen in the world, North America, Minnesota, and in the various Minnesota counties.  Generally I do not chase after birds.  For one thing, they have usually flown away by the time I get to their previous locations.  But, nevertheless, yesterday I drove over to Prescott WI in hopes of seeing a Long-tailed Duck that has been reported off and on this winter.  Here are my photos of it!  I was standing in Wisconsin, but the bird was variously in Dakota and Washington counties of Minnesota.  I trust that counts for my Minnesota list!

House Finches

I wrote the following for The Natural Source, a now somewhat dated on-line resource for environmental educators (http://www3.northern.edu/natsource): "The spread of the house finch across eastern North America has been a startling ornithological event. This bird is native to the western United States, including the Black Hills, but its spread to eastern South Dakota has come from the east. In 1940, house finches were introduced to Long Island, New York and they have spread back westward ever since. The species was first observed in Aberdeen in 1985. Sightings of the species in eastern South Dakota were frequent by the early 1990's, as can be seen by the Aberdeen banding data in Table 1. The species is now abundant across the state." (1996-2004 data are in addition to the original publication.)

Year	# of Birds Banded
1985	1
1986	0
1987	0
1988	0
1989	0
1990	4
1991	13
1992	128
1993	121
1994	447
1995	499
1996	542
1993	121
1994	447
1995	499
1996 1997 1998 1999 2000 1001 2002 2003 2004	542 110 33 267 169 162 241 101 118

Curiously, since 2006, I have  banded only four House Finches in Minnesota.  I reported to you my most recent catch, the bird above, banded yesterday (another photo taken of a bird in front of snow).  I wonder what is happening here.  Are we just "behind" the invasion wave here in Minnesota?  Has the species become less common?  Has the finch eye disease knocked them back? Are House Finches just less common here than in South Dakota?  (I do see House Finches often enough in Minnesota.)

American Goldfinches

This morning for the first time in 2010 I was able to band birds.  About 200 American Goldfinches swarmed at the banding station.  I banded a dozen.  I also caught a single House Finch and Pine Siskin. Many non-banders are unaware that, in the field, you call tell the sex and often the relative age of most basic-plumaged (winter) goldfinches.  I thought I would share these photos with you.  (The photos were taken against a snow drift, hence the white backgrounds.)

Male and female American Goldfinches can be told apart by their wing color: jet black in males, charcoal in females.

Female American Goldfinch with charcoal-colored wings.  Because it is now February, this bird is aged as AHY, or After Hatching Year.

Compare this male goldfinch's jet-black wing with the female's charcoal wing.  We can take the aging of this male bird further than we could the female.  Note the dull shoulder color of this male: this color indicates it was born just last year, hence a SY or Second Year bird.

Compare that color to the bird below.

Since it takes two years of Goldfinches to molt into these bright yellow shoulders, it is aged as ASY, or After Second Year.  Often this color can be noticed in a male with a folded wing.

Because goldfinches of all ages suffer equal mortality, by this time of year anyway, one would predict dull-shouldered SY birds will outnumber older, brighter-winged birds.

Anhingas, oil glands, and corrugated tail feathers

Erika and I saw many Anhinga during our recent Florida trip.  Anhingas are also called snakebirds because of their habit of swimming with only their long necks above water.  (The word Anhinga comes from a Brazilian Indian word for devil bird.)

Before writing up this blog entry, I had always assumed that birds' oil glands water-proofed their feathers, and that the Anhinga's habit of habitually holding their wings out to dry might mean they might lack an oil gland.  I have learned, however, that oil glands do not water-proof feathers--ducks with their glands removed still have water-resistant feathers.  The water proofing is in the feather structure. (Cornell Lab of Ornithology Handbook of Bird Biology)

Anhinga feathers are less resistant to water than other birds such as cormorants, which allows Anhingas to do that neck-above-the-water swimming, with their bodies submerged.  But, compared to cormorants, they must spend more time drying themselves out.

Ornithologists are well aware of the transverse corrugations on Anhinga central tail feathers.  These can be seen on the tail of the Anhinga photographed above (click on the photo for a larger image).  I am unaware of similar structures on other birds (perhaps some hornbills?)  None of my sources suggest a reason for this structure. (Notice that this bird has speared what appears to be a sunfish, and that its head feathers are remarkably wet.)

Florida

When folks return from trips, I always ask what was the best bird they saw.  In January 2010, Erika and I traveled to Florida, where friends invited us to spend two weeks at their condo on Sanibel Island.  We had a wonderful trip, adding about 120 species to my 2010 bird list.  Ever since Audubon's time, Florida has been famous for the tameness of its birds.  There are fewer birds in Florida now, but many of them are remarkably tame--a bonanza for a photographer.  My ever-growing Picasa site, http://picasaweb.google.com/danerika/Florida, has many of the pictures we took.

So what was my favorite bird?  Has to be the Florida Scrub Jay, since this was my 713th "North American" bird sighting.  (North American is in quotes since I count my North American birds wherever I see them, even outside the continent.)  We found the Florida Scrub Jay in the Merritt Island National Wildlife Refuge, just north of Cape Canaveral.  We had unsuccessfully searched for the jay for a day and a half, when Erika suggested we try the "Scrub Jay Trail."  "Unlikely," I replied, "How can they know there will be Jays down that particular trail?"  But, sure enough, at the far point along the trail, this Florida Scrub Jay tamely awaited us.

Erika's favorite bird is probably the Limpkin, found by some local birders for us.  They took us right to the spot, just east of Fort Myers, and there they were, three of them.  We walked for about an hour, but upon our return the Limkins were nowhere to be found (although we did hear them wail from the swamp).  The Limpkin is a bird we first found in Ecuador, so it was not new for our list, but this was our first North American sighting.

We missed seeing any Sail Kites.  This species apparently disappeared from the Fort Myers region just before the recent Florida freeze.  Nobody knows exactly why.  The kite was common enough in early December.

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.)

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