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!

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.

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

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.

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.