Tuesday, April 30, 2013

Wood Duck

A pair of Wood Ducks visited our Dundas banding station. Although I am not permitted to band waterfowl, we did enjoy the extravagant male and the more subtile, but no less beautiful, female. Wood Ducks are slim birds, able to nest in abandoned Pileated Woodpecker holes, and have large eyes so to more easily fly through woodlands.

In the early 1900s, birders feared Wood Ducks might become extinct—they were over-hunted, forests were being cut down, and wetlands drained. Numbers rebounded mid-century, perhaps due to legal protection and introduction of nest boxes along many waterways. Increasing beaver populations have also created more Wood Duck habitat.  Although less hunted than in previous years, Wood Ducks are still prized by hunters. In the eastern United States, this species comprises ten percent of the duck harvest, second Mallards in the number of birds killed (Hepp and Bellrose 1995).

Monday, April 29, 2013

Diving Horned Grebe

Horned Grebes usually feed in water six meters or less in depth (Stedman 2000). Last week I photographed this grebe in Goodhue County, Minnesota, along Lake Byllesby. I believe the water under this bird is about a meter deep. These grebes swallow small prey under water, but disable larger prey with their bills on the surface. They will also occasionally take flying insects from the air or glean other arthropods from the water surface. About 35% of their diet is fish, while 46% is insects—the rest is composed of crustaceans, small frogs, salamanders, leeches and tadpoles (Stedman 2000). Dives last for up to a minute.
As you can see in the final series of photographs, Horned Grebes are foot-propelled divers. First the grebes flatten their plumage to expel air from between the feathers and their bodies. As they begin their dives, Horned Grebes can spread their feet and legs out to the left and right—this allows them to leap almost straight up and then arch down into the water. When diving, they do not use their wings, which are only used underwater to make sharp turns or avoid danger. In the final photo, only a small splash of water remains—a splash that would please an Olympic diver. A close examination of these photos also reveals that drops of water remain on the grebe’s back throughout the dive!

Saturday, April 27, 2013

Vesper Sparrow

The scientific name of the Vesper Sparrow, Pooecetes gramineus, derives from Lain and Greek for “grass dweller” and “fond of grass” (Jones and Cornely 2002). This species thrives in grasslands but declines when such habitat becomes rare (see my post of 17 April 2011). I took this photograph near Northfield after our late April 2013 blizzard—certainly a candidate for inclusion in a future version of my White Album of bird portraits. A storm like this one is probably tough on these sparrows—experimental data on captive birds show adverse effects after ten hours of fasting.


Friday, April 26, 2013

Purple Finch

Purple Finches are visiting our feeders. They are known to eat seeds, fruits, and buds from a wide variety of trees and wildflowers. Obviously they are partial to sunflower seeds. They also take insects. Purple Finches tend to be “quasicyclical,” their numbers vary, depending on yearly production of conifer seeds (Wootton 1996). Elsewhere I have posted on this species’ plumage characteristics.

Thursday, April 25, 2013

Junco Eats Suet

This photo is of a junco at our suet feeder in Northfield, Minnesota, during Monday’s 7-inch ice and snow storm. Although juncos are known to consume Spruce Budworms in quantities, Nolan et al. (2002) do not include suet in their list of juncos’ diets. Captive birds increase fat and protein consumption during long light regimes. In any case, the recent snowfalls and cold weather seem to have halted the junco migration here in central Minnesota; juncos have swarmed around Northfield for the last few of weeks. Since 31 March, I have banded over 600 Dark-eyed Juncos!

Wednesday, April 24, 2013

Swamp Sparrow

Mowbray (1997) writes that no data exist for Swamp Sparrow nutrition, metabolism, energetics, or temperature regulation. Erika and I came upon this sparrow after a record cold night last Saturday in the Minnesota Valley National Wildlife Refuge in Bloomington, Minnesota. The bird was more interested in the seeds melting from the ice than us.

Tuesday, April 23, 2013

Yellow-rumped Warbler

The Yellow-rumped Warblers have arrived. I banded several during the past few days. Previously I have posted on this species’ adaptations for cold weather. Unfortunately for this bird, eight inches of snow fell yesterday night. The photos below show one of my banded birds landing on the baffle below my suet feeder. The bird looked up and discovered the suet, which it proceeded to devour as sleet became heavy snow on April 22nd!

Sunday, April 21, 2013

Snowy Great Egret

Yesterday, the first sunny day in the past week, Erika and I strolled in the Minnesota River National Wildlife Refuge in Bloomington, Minnesota. The night saw record 25 degree temperatures which, in turn, followed a nine-inch, mid-April snow-fall. This forlorn Great Egret probably regretted its return to Minnesota. The area in which we hiked, a series of small pools named the Bass Ponds, are spring fed. Other lakes contained open water, so at least the egret did have access to food sources. Despite objections by some English professors and editors, a snowy Great Egret seems to be a good argument for the capitalization of the common names of birds (and other animals and plants).

Friday, April 19, 2013

Black-tailed Gnatcatcher vs. Coachwhip

In my last post, I cautioned snake-phobic birders to keep one eye on the ground. Occasionally snakes are even above in the trees! Erika and I encountered this Coachwhip in the trees surrounding Quitobaquito Springs in the Organ Pipe Cactus National Monument. We were researching a college senior project more years ago than we care to remember. In fact, now the springs are difficult to visit due to narco-terrorist threats.

Coachwhips are desert snakes and often active in the heat of the day when other snakes seek shelter. They are usually found on the ground, but, as you can see, this snake is also arboreal. Erika and I had been studying the nest of a Black-tailed Gnatcatcher, a common bird of the desert Southwest. The gnatcatchers laid eggs and hatched young. The morning we found the Coachwhip, the nest was empty—perhaps not enough evidence to convict the snake, but sufficient to cast suspicion. Coachwhips are an "impressive predator that eats a wide variety of animals including lizards, snakes (including rattlesnakes), mice, birds, insects, bats, frogs, toads, and small turtles” (Reptiles of Arizona).

Thursday, April 18, 2013

Eastern Diamondback Rattlesnake

While birding in many parts of the country, keeping an eye to the ground is often advisable. Eastern Diamondback Rattlesnakes are found along the coastal plains of the southeastern United States, from North Carolina and Florida to eastern Louisiana. Displaced by human development, the snakes now appear in unexpected habitats (Florida Museum of Natural History). Erika encountered this individual in the parking lot of that premier birding location, Corkscrew Swamp. Park rangers quickly set up a monitor but did disturb the snake.

These large rattlesnakes (some reach lengths of seven feet) are potentially dangerous, so disturbing one is a poor idea. If given the opportunity, this rattlesnake will usually retreat. But, if cornered, some stand their ground, striking repeatedly. Not all rattle before striking and, indeed, there may be selective pressure to remain silent and unnoticed. These snakes are beneficial, preying on a variety of rodents and rabbits that are generally considered to be pests. Nonetheless, many are killed on sight by the general public. Consequently Eastern Diamondbacks have suffered severe population declines (Wikipedia).

Tuesday, April 16, 2013

Northern Mockingbird

Another bird from our recent Washington, DC, trip was this Northern Mockingbird. This remarkably tame bird attracted us by expertly mimicking a Tufted Titmouse. Male mockingbirds often have repertoires of over 150 song types—a repertoire that increases with the bird’s age. They mimic both other birds and various mechanical sounds (such as trains or traffic).

Adults may spend the year in a single territory. Others enjoy different territories in winter and summer. Male and female mockingbirds split up parental care, with the female doing all the incubating and most of the brooding of young, and the male providing food. This division of labor allows them to produce up to four broods per season. Despite this fecundity, mockingbirds are declining in the south (but increasing northward) (Farnsworth et al. 2011).

Monday, April 15, 2013

Ring-necked Duck

Perhaps more aptly named Ring-billed Duck, this species does sport a brown neck ring between its dark head and breast. Ring-necked Ducks beed across central Canada and in the United States in the upper Midwest and in isolated areas through the Rocky Mountains. Although seasonally monogamous, only the female provides parental care (Roy et al. 2012).

They winter across the southern United States, Mexico, and the West Indies. In winter, they consume plants. Although vulnerable to hunting, their populations are stable or increasing (Roy et al. 2012). This spring, I found this male on the Potomac River just north of Great Falls National Park. I previously posted photos of a Ring-necked Duck pair from Minnesota.

Saturday, April 13, 2013

Ivory-billed Araçari

Erika and I took this photograph of an Ivory-billed Araçari during our graduate research in Peru. This species is among the smallest of the toucans. We liked toucans until we learned that one use for their odd bills is robbing other birds’ nests and eating the young and eggs. Toucans turn up in avicultural trade, and owners are warned not to cage them with smaller birds (birdchannel.com). Toucans also consume a variety of arthropods, fruits and nuts. Of course, all pet owners should take absolute precautions that their birds are both legally imported and not wild-harvested.

Friday, April 12, 2013

American Tree Sparrow

Although American Tree Sparrows are abundant wintering birds in Minnesota, I band relatively few of them. In fact, the photograph here is my first for my white-background series. As most of you know, I wrote a book of 91 of these photographs. You can see a preview of almost half of these pictures by clicking on the book cover on the upper right-hand side of this blog (look for the side view of the male cardinal).

Tree sparrows are cold-tolerant species (as I mentioned in a previous post). They breed across northern Canada, often north of the tree-line. They consume weed seeds. The species was named for its superficial resemblance to the  Eurasian Tree Sparrow, a bird not even in the same family.  

Wednesday, April 10, 2013

Eastern Phoebe

Amidst rain and snow, the Eastern Phoebes have returned to our backwoods. One wonders what food they are finding. The one phoebe I’ve banded was very thin. These photos have been lying around in my computer for a couple of years, so I thought I would share them with you now.
The second photo shows a phoebe nest at a garage at our Dundas feeding station. The phoebe’s choice of nesting in buildings and under bridges resulted in a westward spread in range in historic times. They still, however, occasionally nest in rock outcroppings. Recent DNA studies indicate that, although the adults are “socially monogamous,” phoebe young are the result of “considerable extra-pair paternity and polygyny" (Weeks 2011). The last phoebe is a bird photographed last summer at the University of Minnesota Landscape Arboretum.

Tuesday, April 9, 2013

Dark-eyed Junco

This week we witnessed a huge influx of Dark-eyed Juncos. Most are the slate-colored form. Two were the Oregon race (see lower photo and post of 23 March 2010). The bird above was feeding on a dead weed, either eating seeds or searching for insect larvae. Note that this junco is probably mine—the band is still new and shiny, and the band is on the left leg. Although I banded 197 juncos this week, very few of the birds currently at the feeders, and neither of two Oregon Juncos, are ringed—yet.
Speaking of banded birds, fewer banded birds are reported to the Bird Banding Office now than in the 1920s and 30s. Several hypotheses are suggested. Are permits these days restricted to specific scientific studies and not issued to “recreational” banders, resulting in fewer birds banded or recovered? Are people now less willing to cooperate with the Federal government? Are folks worried about legal ramifications of reporting dead migratory songbirds? Are young people glued to their video games and less likely to be exploring outdoors? Are fewer people hunting and not outdoors?

Sunday, April 7, 2013

Bufflehead

This female Bufflehead in the Reflecting Pool in Washington DC reminded me of my first discovery of this species. I was in high school, and the Hooded Merganser had become a nemesis species for me. No matter how hard I searched, I could not add the merganser to my life list. I did find a female Bufflehead in a local pond. Did the white stripe on the head indicate a Hooded Merganser? After some agony, I concluded I had yet to find a Hooded Merganser—the white stripe was just too low on the head. Look at the up-turned tail on this photo. Beginning birders might take this posture for a Ruddy Duck.

The Reflecting Pool, a shallow, cement-lined, shallow, rectangular lake between the Lincoln Memorial and the Washington Monument, seems like an unlikely habitat for diving ducks. What could the ducks find to eat? They search for insect larvae, amphipods, and other small arthropods. The Reflecting Ponds seemed to be fairly sterile, but NBC news reports that, despite a $34 million renovation, the Reflecting Pools are full of algae, which must support enough arthropods to keep the Buffleheads fed.

We encountered a Bufflehead pair in the pool. Buffleheads are monogamous and are among just a few ducks that maintain the same mate for several years. Buffleheads are often shot by hunters, but populations have increased since the 1950s (Gauthier 1993). Also in the pool dove a half-dozen Lesser Scaup, photos of which I will share in a future post.

Saturday, April 6, 2013

Red-stained Woodpecker

Red-stained Woodpeckers are locally common inhabitants of the Amazon basin. They forage in the forest canopy and also follow army ant swarms to feed on flushed arthropods (de Hoyo et al. 2002). Erika, James Yost, and I took this photograph in Ecuador using a captive bird inside a photography box covered with blue parachute cloth—look at the blue “sky” in the upper right edge of the photo.

Thursday, April 4, 2013

Mallard

My fellow blogger Penelope commented, on my last post on the beauty of cardinals, that she also considers the Mallard to be stunning. Judging by this photo of a drake Mallard, Penny has a point! Although Mallards are the most common of the North American ducks, found in urban and wild areas around the world, birders seldom take a second glance at them. The recurved black central tail-feathers, from which comes the term "duck-tail" hair styles of some 1950s teenage boys, are alone worth a second look. I took this photo, presumably of a wild bird (scaup and buffleheads were also present), along the Reflecting Ponds in Washington, DC. during our recent visit.

Wednesday, April 3, 2013

Northern Cardinal

Northern Cardinals are omnivorous, eating seeds, fruits, and insects. Their color is derived from carotenoid pigments from their food. The brighter the male, the better is his reproductive success. Brighter males have richer territories and are better able to feed nestlings (Ikin and Linville 1999). This cardinal, photographed on Tuesday, certainly seems to be a top-dog male. Sometimes we don’t appreciate the beauty of our most common birds—imagine if this were the first time you ever saw a cardinal!

Monday, April 1, 2013

Carolina Chickadee

Sharp demarkation between the black throat and white breast, relatively uniform gray wings without frosty white feather edges, and a northern Virginia location all add up to Carolina Chickadee (see my post of 17 January 2012). Only 40 to 60 percent of chickadees survive the winter, when they form territorial flocks. In the spring, dominant males and females breed within these territories. Non-nesting birds are either forced off the territory or remain as non-breeding “floaters,” ready to take the places of deceased breeders (Mostrom et al. 2002). The red splotch behind the chickadee in the lower photo is a fleeing Northern Cardinal (not seen by me when I took the picture).