Wednesday, March 31, 2010

Eastern Phoebe

Today, 31 March 2010, I banded the first Eastern Phoebe of the year.  Scott Weidensaul, in his excellent book Of a feather: A Brief History of American Birding, reports Audubon "banded"  the first birds in North America when he tied silver thread to two phoebes.  The birds returned to his Pennsylvania farm the next year.

Monday, March 29, 2010

Purple vs. House Finch

Today I banded a male and "female" Purple Finch.  Beginning and casual birders sometimes confuse Purple and House finches.  The Purple Finch (above) is wine-colored, whereas the House Finch (below) is more of a brick red.  Note also the flanks and the heads of the two birds: the flanks on the Purple finch are basically reddish, whereas the House Finch flanks are definitely brownish streaked; the House Finch head is more uniform than the Purple Finch's.  Look at the dark cheek and burgundy eye stripe on the Purple Finch.
The sides of the head of the "female" Purple Finch (above) are also more striking than those of the female House Finch (below).  Identifying finches in these plumages is usually a fairly easy call (at least east of the Rockies; out west different races of the two species are more similar). But the discussion gets more complicated!
Many birders are unaware that the male Purple Finch does not molt into his red plumage until his second September.  The result is that telling the sex of second-year Purple Finches is probably impossible in the field.  That's why I labeled my photograph as "female"--the bird could well be a second-year male!  Male House Finches, on the other hand, become red during their first fall.

Saturday, March 27, 2010

Fox Sparrow and Kinglet

In South Dakota my best banding occurred under cloudy skies during migration.  My working hypothesis was that, under clear skies, many woodland migrants overflew northeastern South Dakota.  Before White settlement, little or no forest habitat existed in the prairie.  Only bad weather would bring down the migrants, and now towns offer a refuge for them.   I went out with high hopes this cloudy Saturday morning and spent about two hours banding.

One species I see more frequently in Minnesota than I did in South Dakota is the Fox Sparrow (see photo above).  I banded the first of 2010 this morning.  In both states, to the best of my recollection, I have only caught the reddish race of this species, P. i. iliaca.  Further west, in the Rocky Mountains and along the Pacific Coast, 16 additional darker and grayer races occur.  These races sort out into four groups; as a result of DNA studies, these groups are likely to be split into four species (with various races).  The Slate-colored Fox Sparrow, P. i. schistacea, of the Rocky Mountains might be looked for as a vagrant to the Dakotas and Minnesota. (Sibley in his Guide to Birds illustrates the four groups of Fox Sparrow races.)

Other birds banded today include 9 Slate-colored Juncos, 1 Black-capped Chickadee,  2 American Goldfinches, and a female and male Golden-crowned Kinglet (photographs below).

Thursday, March 25, 2010

Blue Jays

John Trott, the seventh grade teacher who introduced me to birding, claimed that Blue Jays are so beautiful that they would be everyone's favorite birds were they not so common and aggressive. 
Blue Jays in the hand, and perhaps in the field, can be aged by the color of the insides of their upper mandibles.  Birds with white-lined, inner mandibles are young, after hatching year birds have black linings. Thanks to S. R.'s sacrifice of his finger, this Jay's inner mandible color is clearly black, not white.  But by January, most Blue Jays mandible linings have turned black (and this bird was caught on 22 March).  But there is another way to age Blue Jays.
Note the alula feather and the primary coverts in this photo.  (The alula is the first, broad, short wing feather, and the primary coverts overlap the outer flight feathers.) These feathers on this bird are uniformly blueish.  Adult birds have dark bars on these feathers.  This bird, therefore, is a second year bird--this summer will be its first breeding season.

Tuesday, March 23, 2010

"Oregon" Junco

Yesterday I banded the "Oregon" form of the Dark-eyed Junco.  Note the black head, brown back, and pinkish sides.  Also note the angle formed where the sides meet the dark throat--usually forming a relatively sharp angle. Compare that angle with the rounded curve formed by the gray throat and sides of the "Slate-colored" Junco in the photograph below.
"Slate-colored Juncos" breed "across boreal n. North America south to w.-central Alberta, east to Newfoundland, and south through Appalachian Mtns. to n. Georgia."  Oregon Juncos "breed over much of w. North America, from se. Alaska south to mountains of n. Baja California and east to sw. Saskatchewan and w. Nevada; casual or accidental to East Coast and west to w. Alaska."

Years ago these birds were considered to be separate species, but, because they interbreed where their ranges meet, they were lumped together as one, now called the Dark-eyed Junco. Hence the quotes around "Slate-colored" and "Oregon." Indeed, Thomas Roberts in his 1936 classic, The Birds of Minnesota, wrote that many migrating juncos in the state are hybrids between these two juncos.

But listers beware!  Nelson et al. (see next paragraph) tantalizingly suggest "reappraisal and further study in light of prevailing views on the importance of hybridization and introgression seem likely to lead to recognition of several species in the future."

Range quotes are from: Nolan, Jr., V., E. D. Ketterson, D. A. Cristol, C. M. Rogers, E. D. Clotfelter, R. C. Titus, S. J. Schoech and E. Snajdr. 2002. Dark-eyed Junco (Junco hyemalis), 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/716

Finally, note the pale white wing bar in the photo of the lower junco photo.  White wing bars occasionally occur on "Slate-colored" Juncos and should not be misidentified as the "White-winged" Junco of the Black Hills.  Those birds are bigger, grayer, and even more distinctly wing barred (and not to be expected in Minnesota).

Monday, March 22, 2010

Banding 22 March 2010

Spring has arrived! Our totals at Dundas for this morning were:

1 Blue Jay
1 American Tree Sparrow
13 Dark-eyed ("Slate-colored") Juncos
1 Dark-eyed ("Oregon") Junco
6 American Goldfinches
5 Northern Cardinals
1 Hairy Woodpecker

Plus a Black-capped Chickadee originally banded on 26 October 2009.

The tree sparrow is only the second banded at the Dundas site.  I wonder why such a common bird in Minnesota is so rare in my banding nets.  In South Dakota I averaged 22.2 tree sparrows a year.  In 1996, in my residential backyard, I banded 255!  The migrating tree sparrows were almost like streams of protoplasm, which fortunately flowed right into my net.  I have not seen anything like that since.

Notice that the American Tree Sparrow photographed above lacks the distinct breast spot indicated in most field guides.

I will have more to write about the Blue Jay and the "Oregon" Junco in future blog postings.

Thursday, March 18, 2010

Black-capped Chickadees

Aldo Leopold in his classic book, A Sand County Almanac, writes of banding Black-capped Chickadees in Wisconsin. Of 97 banded during the 1930s, only one lived to be five years old. He also figured their winter range was about a half mile. Birds dispersed further afield after the winter, with many of his banded chickadees mating with unbanded ones in the spring.

So it is with my chickadees (although I retrapped two of my chickadees banded in Northfield near Dundas, about two miles south of Northfield banding station. Both were banded on 21 August 2008 and recovered on 10 September 2008. One of these birds was subsequently retrapped near Dundas on 21 September, 2 October, and 14 November (all 2008)).

I caught three chickadees this morning in Northfield: to my surprise, two where unbanded. The third was banded locally on 28 October 2009.

Do Black-capped Chickadees migrate? Carol Tveekrem once wrote me that there is a definite southward movement of Black-capped Chickadees along the North Shore of Lake Superior in Minnesota. I am unaware of any banded Minnesota chickadee recovered outside of the state. Chickadees in New England are reported to move into more southern states during very cold winters. Most of our Minnesota winters are considered to be very cold...

The oldest banded chickadees in Minnesota (according to Bird Banding Lab records) are two 9 year-old chickadees. Both were recovered near to their banding locations. The national longevity record for this species, according to the Banding Lab, is 11 years, 2 months (http://www.pwrc.usgs.gov/bbl/homepage/long6882.cfm#Chickadee). (The bird was banded and recovered at the same location in Massachusetts.)

Finally, I am surprised by my chickadee photograph. This species clearly seems to possess binocular vision--undoubtedly helpful for flying through the forest!

Thursday, March 11, 2010

Dark-eyed Juncos

 
After almost a week of fog and rain, I have not been able to do much field work.  Despite the rain, I have heard and seen more robins and juncos than I have previously this winter.  Perhaps these birds represent the vangard of the spring migration!

Check out this website for a detailed account of how to age and tell the sex of juncos and a few other birds: http://www.migrationresearch.org/mbo/id/scju.html#asyfw.  The site is intended for banders with birds in hand.  Some birders say that you can tell the sex of juncos by the amount of white in their tail feathers: this is a misconception--the amount of white is simply variable regardless of age or sex.  According to the website, banders can tell the age and sex of juncos by small differences in the wing covert shapes and colors.  I have always depended upon wing length and eye color.  Birds with wings under 72 mm are females, those 78 and more are male (with intermediate wings of unknown sex).  Under bright light, juncos with brown or grayish eyes are either hatching year or second year birds (depending on the season) while those with rich chestnut eyes are after-hatching birds.  The bird above has chestnut eyes.

Thanks to Larry Sirvio for giving me the lead to http://www.migrationresearch.org/mbo/id/scju.html#asyfw.

Friday, March 5, 2010

Hairy and Downy Woodpeckers

Most birders do not have too much trouble identifying Downy and Hairy woodpeckers. 
The Downy Woodpecker is smaller than the Hairy and the Downy's bill is definitely shorter than the head is wide.  On the other hand, the larger Hairy Woodpecker's bill is usually at least as long as the head is wide. 
It surprises me, then, when I have trouble telling the relative size of the two species, specially here in Minnesota. Sometimes I have to check the  tail feathers of the woodpecker in question.  Downy Woodpeckers almost always have two spots or bars on their outer tail feathers. 
Compare the Downy Woodpecker tail above with the enlarged photo of a Hairy Woodpecker below.  The black tail bars are absent on the Hairy Woodpecker.  (I have only very rarely banded Downy Woodpecker with white outer tail feathers--so this field mark is not fool proof.)

As far as size goes, I wondered if my difficulty with relative size was due to actual differences or just to my aging eyes.  I may be correct in thinking Hairy Woodpeckers are smaller in Minnesota.  Two of the 17 races of Hairy Woodpeckers are found in North Dakota, South Dakota, and Minnesota. The Northern Hairy Woodpecker, Picoides villosus septentrionalis, is found north of us (and in northeastern South Dakota and perhaps in extreme northern Minnesota). The northern bird is larger and whiter than the Eastern Hairy Woodpecker Picoides villosus villosus, the race expected in Northfield (and in most of Minnesota).  In these photos, the bottom two Hairy Woodpecker photos were taken in Aberdeen, South Dakota.  Note how white this bird is compared to the Minnesota photo at the beginning of this blog entry! The Northern Hairy Woodpecker does range further south in the winter, and perhaps, as indicated by these photos, could be identified in the field.

My sources for this information are Roberts, The Birds of Minnesota, UM Press 1936 and also Jackson, Jerome A., Henri R. Ouellet and Bette J. Jackson. 2002. Hairy Woodpecker (Picoides villosus), 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/702

Monday, March 1, 2010

Winter Banding

With today's relatively warm weather, I opened my banding nets for the first time in 2010. I caught about ten birds, including this White-breasted Nuthatch, originally banded on 8 July 2009--by no means a remarkable recovery, but nice to see that this individual is surviving the winter.
Northern Cardinals bite so hard, they are among my least favorite birds to band.  This male is about ready to let me have it! I think it is interesting that Cardinals at the banding station have greatly increased in numbers since last December.  I assume that this increase is due to post-breeding dispersal, rather than a true migration--but I am not sure.

I also banded American Goldfinches, a Downy Woodpecker, and several Dark-eyed Juncos.  I will have more to write about the later two species in the next couple of days.  One species I did not catch is the American Tree Sparrow.  Indeed, in what looks like ideal habitat to me, I have only caught one American Tree Sparrow in the last three years.  These birds are common elsewhere in the winter and during migration, so I am not sure why I don't band them more frequently.

Again I took these photos against a snowy background.  I think this makes for interesting portraits, but, with temperatures predicted in the 40s for the rest of the week, perhaps my snow will begin to melt.