Saturday, November 22, 2014

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.

Friday, November 21, 2014

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.

Wednesday, November 19, 2014

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).

Monday, November 17, 2014

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.

Sunday, November 16, 2014

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.

Saturday, November 15, 2014

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.

Thursday, November 13, 2014

Cliff Swallow

The last photograph we took on our return from Olympia on 25 July 2014 was this Cliff Swallow as it peered from its nest under a South Dakota Interstate overpass. Both sexes build their mud nests. They gather mud, usually within a half-miles of their colony. They bring the mud to the nest and mold it with a shaking motion of their bills. The result is a hollow ball, often with a long, downward entrance tunnel. Birds will often steal mud from nearby nests. The nests are lined with grass, either gasthered nearby or taken form other nests. Nests are generally finished after a day, but are maintained during the breeding season. Unmated males may take over existing nests or begin building a nest in hopes of attracting a female (Brown and Brown 1995). Cliff Swallow colonies can be quite large, often numbering in hundreds of nests.

Tuesday, November 11, 2014

Red-necked Grebe

On our trip home, we split our traverse of endless Montana by taking an extra day to cross the state. On 24 July 2014, we left the Interstate and drove south on State Route 1 up to Georgetown Lake before the highway heads straight east and back to the Interstate. Our target species was the Red-necked Grebe, a bird we lacked for our Year List. We saw this grebe at this location many years ago, so I thought we stood of tolerable chance of seeing it again.

Red-necked Grebes are found from Alaska and northwest Canada, dipping south into Minnesota, the Dakotas, Montana and Idaho—I have also seen the species in South Dakota and Minnesota. They also breed across Asia to Europe. Our birds, as are those from eastern Asia, are larger than European populations. Until 1957, these larger birds were thought to be a distinct species, the Holboell’s Grebe.

As we hoped, we had no difficulty finding a Red-necked Grebe along Georgetown Lake near the highway. This individual swam aggressively back and forth—perhaps the nest lay among some reeds in nearby shallows. In the second photo, note the raised tufts on the back of the head. These crests are often raised during defensive displays (Stout and Nuechteriein 1999).

Sunday, November 9, 2014

Pileated Woodpecker

This odd-looking photograph was taken on a heavily overcast summer day. The picture, taken with a very low shutter speed, captures the essence of a Pileated Woodpecker feeding on the ground—which they do on occasion, when not drilling into woodland trees. The woodpecker uses its long, barbed tongue and sticky saliva to feed on ants and other arthropods, which they extract from tunnels in rotten wood and in the dirt.

The second photo was taken on a bright, November 2014 day of a Pileated Woodpecker at one of our suet feeders. For about 30 minutes, the woodpecker also worked decaying trees in the backyard.

Saturday, November 8, 2014

Pygmy Nuthatch

Kingery and Ghalambor (2001) perfectly describe Pygmy Nuthatche behavior: "Frenetic movements—head first, up tree, down tree, along branches, right-side up and upside down—accompanied by constant chatter, convey the busyness and nervous activity of this gregarious bird as it searches for food.” Certainly this was true for a flock of nuthatches Erika and I found at an Interstate Rest Area in Coeur d'Alene, Idaho, on 23 July 2014. Photographing them was difficult as they bounced through the shady, pine understory.

The species is found in Ponderosa Pines in Western North America and in Mexico. This species is one of the few in North America that practices cooperative breeding. About a third of breeding pairs have up to three male helpers, usually related from previous nests. The helpers feed incubating females and the young and defend the nesting area. Family groups also flock together and with other species, to which they generally are socially dominant. During cold weather, Pygmy Nuthatches are capable of controlled hypthermia as they roost together.  Stacks of up to ten or more birds huddle together, and two articles report more than 150 birds roosting in one tree (Kingery and Ghalambor 2001).