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).
Tuesday, April 30, 2013
Wood Duck
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!
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
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
Tuesday, April 23, 2013
Yellow-rumped Warbler
Sunday, April 21, 2013
Snowy Great Egret
Friday, April 19, 2013
Black-tailed Gnatcatcher vs. Coachwhip
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).
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
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
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
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
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
Wednesday, April 3, 2013
Northern Cardinal
Monday, April 1, 2013
Carolina Chickadee
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