Common Eider

With Common Eiders being reported from Duluth in November 2014, I searched my blog for photos I knew I had taken off Martha's Vineyard in September 2009. To my surprise, I have not shared this photo with you.

Common Eiders are the largest ducks in the Northern Hemisphere. The Duluth birds aside, eiders are usually restricted to coastal oceans. An Arctic breeder, many winter as far north as open water remains. Eiders were historically over-hunted, almost to extinction in eastern North America. Populations are now stable despite “increasing harvest pressure" (Goudie et al. 2000).

Purple Finch

On 20 November 2014, while driving across the fields west of Northfield, John Holden and I found a Purple Finch in a farmyard crabapple tree. This species is common across much of the northern United States, southern Canada, and the west coast of North America. This finch winters in much of the eastern United States, where it feeds on buds, fruits, seeds. Purple Finches often are seen at bird feeders.

Purple Finches enjoy “quasicyclical” winter irruptions (Wootton 1996). I assume “quasicyclical” means that finch winter population numbers vary from year to year, but not as predictably as those of other winter finches. Presumably these population swings are the result of yearly variation in northern conifer seeds.

This male Purple finch is at more two years old. First and second year males look like females. Males do not molt into their red plumage until their second September. I shared photos of female-appearing birds in a previous blog post.

American Tree Sparrow

On 14 November 2014, Erika and I explored Dakota County’s new Whitetail Woods Regional Park, well worth a visit if you are in the area. The park sports many hiking trails through rolling prairie and woodlands and a small but gorgeous lake.

On this chilly day, we found a flock of a couple of dozen American Tree Sparrows. Naugler (2014) suggests this name is a misnomer, since most of these sparrows breed, often beyond the treeline, in the far north of Canada and Alaska. They winter across most of the northern United States and southern Canada.

Their winter diet includes a wide variety of seeds—about 50% grass, 40% weeds, and 10% other plants. In the summer this diet switches over to nearly 100% animal matter. Naugler (2014) further reports that captive birds drink 29.6% of their body weight in water each day and that wild birds eat snow in the winter. This species is a cold-hearty bird, because, as we Minnesotans well know, eating snow for survival often results in hypothermia in other creatures.

Two races of American Tree Sparrow are described—eastern and western subspecies. Western birds breed in Alaska and adjacent Canada while eastern birds summer across most of northern Canada. Eastern birds have more chestnut, less cinnamon-colored crowns, broader back stripes, and gray rather than whitish edges to their tails.  I suspect my photo is of an eastern bird.

Cedar Waxwing

On 8 November 2014, Erika and I found a small flock of Cedar Waxwings at the University of Minnesota Landscape Arboretum in Carver County. Becuase of its streaky, unkempt plumage, the bird in the first photo is clearly a juvenal. The second bird sports more compact plumage, but is probably an older bird-of-the-year, as evidenced by less distinct streaks—adults are completely unstreaked.  First Basic Plumage (winter plumage), is acquired from September to December.

Great Blue Heron

During a 31 October 2014 stroll through Carleton College’s arboretum, Erika and I happened upon a late-migrating Great Blue Heron. The rusty-tipped wing coverts indicate this bird is young. Last fall, we also found a late Great Blue, and we found it all the way through December.

As we watched, the heron raised all of its body feathers and then, in the last photo, violently shook them. I was surprised that this behavior is apparently not described by Vennesland and Butler (2011) in The Birds of North America. I assume this shaking is a feather maintenance behavior. The bird was aware of my presence, and it may have been getting its plumage in order in case it decided to flush. I, however, retreated, and the bird walked away.

Red-shouldered Hawk

This week John Holden called to report an oddly colored, orangey breasted hawk perched above his bird feeders near Dundas, Minnesota. “It is relatively tame, and you should have no problem seeing it,” he claimed. Sure enough, on 19 November 2014, when I drove over to see if I could find it, a Red-shouldered Hawk swooped low across his front yard and landed above his backyard feeders.

Red-shouldered Hawks are found in many North American forests and in nearby urban woodlands. The hawks generally hunt from a perch, waiting to spy prey on the ground. John confirmed that his bird spent most of its time looking towards the ground. These hawks eat a variety of vertebrate prey. In Minnesota in the winter, they especially favor chipmunks, mice, and voles (Dykstra et al. 2008). Small birds are also taken, but, curiously, the birds at the nearby feeders paid the hawk little attention (unlike the panic shown when an Accipiter is nearby). Note the bloody belly feathers on the bird in my photo. I suspect those are the result of the hawk’s taking squirrels or chipmunks (and the latter really should be hibernating now). Squirrels are certainly abundant at the feeder. I doubt that smaller prey would leave such a bloody mess.

Janssen (1987) rates this hawk as “casual” in the winter in Minnesota. (Note that Janssen’s book is currently available for a penny through this link—I assume postage is additional.) In the past 30 days, only about a half-dozen eBird records exist for the state.

Pine Siskin

Last week Pine Siskins appeared at the feeder. With the advent of bitter cold and snow, we banded a few on 17 November 2014. I have banded well over 13,000 siskins during my career, and have enjoyed a few notable recoveries. None of the birds at the feeder this year appears to be banded, which you might expect from nomadic siskins.

Siskins are an irruptive species, present one year, often absent the next. One assumes this pattern is due to abundance of seeds that the siskins consume. Siskins are odd in that, if food is abundant in a wintering area, siskins often remain to breed, usually very early in the spring. Even across its Canadian and Rocky Mountain breeding range, just exactly where breeding takes place is determined by food abundance (Dawson 1997).

American Crow

I think of crows as being black. I took this photo at the University of Minnesota Landscape Arboretum on 8 November 2014. After developing the image, I was surprised to find the crow to be a combination of violet and, especially on the outer primaries, bluish-green. The back looked scaly. What a beautiful bird!

Verbeek and Caffrey (2002) describe crows’ Basic Plumage exactly as my bird appears. Juvenal birds are dark gray and very young birds have bluish eyes. Towards the middle of summer, they replace all their feathers and enter into Basic Plumage. Apparently, unlike many other passerines, they lack an Alternate Plumage (formerly known as a Breeding Plumage—they breed, instead, in their Basic Plumage). These authors explain that the scaly look is due to non-interlocking distal ends of the back feathers.

Bald Eagles

On 31 October 2014, Erika and I found two relatively cooperative Bald Eagles along the Canon River in Carleton College’s Arboretum. The raptors perched close by each other. The bird in the first photo seemed larger than that in the second and third. Assuming that the two birds originated from the same area, then the larger bird is probably a female, and, perhaps, the two eagles were a pair. Southern eagles, however, are smaller than northern ones, so, unless you know where they come from, sex can not always be identified by the birds’ sizes.

Both birds peered skyward when a dark juvenal eagle flew overhead. The presumed pair noisily took wing. The female appeared to chase off the male before joining the young bird in flight. The two birds circled the river twice before flying to the north. What appears to be a black band on the bird in the middle photo is an artifact—a shadow from its perch. Both birds appear to be undergoing heavy molt, making them somewhat speckled. This condition means these birds are probably three to five years old.

Review: Thayer Software Birds of North America version 7

Thayer’s Birds of North America is a robust, yet easy and intuitive to use, program that belongs in every birders’ computer. Recently Version 7 has been released. To see how the program works and to find out why you should own it, see my previous review of a previous version, or watch Thayer’s You-Tube video.

There are a few things you should know about this new version.  First, it is only for the Windows platform. A Mac edition is promised for next spring. Next, Version 7 is free if you already own version 4.0, 4.5, 5.0, or 5.5!  Finally, if you don’t own any of these versions, then the price has been cut in half, from around $100 to $49.95. As a reader of this blog, you can use the code “DAN55057” when you place your order, and the price is reduced by $5.00! Orders can be placed at www.OnelineNatureMall.com or through http://www.thayerbirding.com. Because this program is downloaded from the publisher, it is not available through Amazon.com.

Why upgrade? The program now includes 6,504 photos (versus 3431 or fewer, depending on your current version) and the photos are larger. There are 1499 songs (older versions boasted up to 719). 985 species are covered (vs. 970 or fewer). The general layout and the maps are improved. The program now reflects current bird taxonomy. Finally, the number of videos has increased to 552 from 275 in some of the older versions.

One reason for the price reduction is that the program is now delivered by downloading or via a memory stick. The program is very large, at 6.86 gigabytes, and comes in six separate files. Directions for installing are remarkably clear, but, can take several hours if you have slow Internet service.

I am an enthusiastic, long-time Thayer Birding Software user. Readers of my previous reviews will recall that I required this program instead of a textbook in my ornithology classes. The cost was often less than a classical textbook, and The Birder’s Handbook, a 785-page reference book, is embedded in the program. Among many other aspects, what makes this program such a powerful learning tool is the ability to make customizable quizzes (or you can test yourself using quizzes that come with the program). My students were responsible for any species seen during their field trips. We reviewed birds after every lecture, and soon the students knew their birds well. And, if questions about subtle differences between birds arose, then the students could easily compare species by viewing side-by-side photographs. For more advanced birders, this program allows you to import your own photos and videos. Better yet, you can export photos and videos from the program into your iPod or MP3 player.