Saturday, March 31, 2012

Sanderling

This Sanderling photo is from our trip to Sanibel Island, Florida, a couple of years ago. Sanderlings breed in the High Arctic. Although most winter along the coasts of Central and South America, these little sandpipers also winter along all three coasts of North America. Sanderlings are common migrants across the Great Plains.

Sanderlings are easily identified by their white and gray plumage along with their black fore-wings (visible even when the wings are folded). Sanderlings usually feed on sandy beaches, running from incoming waves and chasing after receding ones. They probe the wet sand in search of arthropods exposed by the waves.

Wednesday, March 28, 2012

Red-necked Grebe

In the Western Hemisphere, Red-necked Grebes nest in northwestern North America. They winter off both the Atlantic and Pacific coasts of the continent. I have seen several in Rice County, Minnesota, about the southeastern limit of their breeding range. When I took this photo of a Red-necked Grebe in northeast South Dakota, I did not notice the black and white striped young riding on its parent's back. In its limited breeding area in South Dakota, this grebe seemed to prefer relatively deep lakes, especially those surrounding the Waubay National Wildlife Refuge.

Monday, March 26, 2012

American Dipper

American Dippers, common along roaring western mountain streams, are North America's only truly aquatic passerines (Wilson and Kingery 2001). A couple of records exist from the North Shore of Minnesota. The nearest reliable place to find this species, however, is at Roughlock Falls south of Spearfish, South Dakota (where this photo was taken).

Also called Water Ouzels, American Dippers bob spasmodically along and in their cascading streams. Often they dive into the turbulent water and strangely resurface looking completely dry. You can see droplets of water falling from this dipper's tail! Their streams can be almost freezing. To survive, Dippers have low metabolic rates, and their blood has extra oxygen-carrying capacity. They also sport a thick feather coat.

Friday, March 23, 2012

Nine-banded Armadillo

Last year I took this Nine-banded Armadillo photo in northern Florida. It is somewhat unusual to encounter armadillos in the daytime. Armadillo populations in the south are moving north and east, so more folks will come to know these fascinating creatures. Armadillos are prone to automobile encounters, and highways in the south are often littered with armadillo carcasses in the morning. Our genus of Armadillo, on the other hand, has a high reproductive rate. Indeed, this genus includes the only mammals that always give birth to identical quadruplets!

Armadillos are also one of the few animals that succumb to leprosy. One reason for this susceptibility is that they have body temperatures similar to humans. Much of our knowledge of leprosy comes from armadillo studies. People can get leprosy from handling or eating armadillo meat. Curiously, leprosy was unknown in the New World prior to European exploration. Thus scientists assume that armadillos first acquired the disease from humans (Wikipedia).

Tuesday, March 20, 2012

American Pipit

I took this pipit picture several winters ago as the bird made tracks across the beach at Morro Bay, California. Until recently this species was known as the Water Pipit, found across northern parts of the world, from Great Britain and Scandinavia to North America. In the New World, this pipit breeds in the Arctic and south through the Rocky Mountains. American Pipits winter along our Pacific Coast and across the southern United States and northern Central America.

Genetic studies conclude that our pipits are different from most of those of the Old World. Thus ours is now known as the American Pipit and those of the Old World are still called Water Pipits. The only exception to this pattern is that pipits in the far eastern areas of Asia are retained as subspecies of our American Pipit (Verbeek and Hendricks 1994).

Saturday, March 17, 2012

Pied-billed Grebe

Several Pied-billed Grebes swam among the ducks at Wells Lake last week. This grebe is common across much of the Western Hemisphere. The name comes from the black bar on its bill, visible in the spring. Pied-billed Grebes feed on whatever prey they can catch--crustaceans, grogs, fish, and insects. Usually they dive for these items, but they also feed from the surface, and, even, occasionally in midair. (I previously posted on the biology of this species in October 2010.)

Thursday, March 15, 2012

Northern Shoveler

I usually think of Northern Shovelers as being relatively late spring migrants.  They were, however, among the first ducks to appear at Wells Lake this spring. The males are relatively easy to identify.  The females appear similar to hen mallards, but with out-sized bills. While swimming, the ducks feed by dabbling their big bills, straining small crustacans from the water. This photo of a shoveler pair was taken several years ago in South Dakota.

Tuesday, March 13, 2012

Hooded Merganser

Last Wednesday, Hooded Mergansers were common on Wells Lake near Fairbault. Most Minnesota birds winter along the Mississippi Flyway and eastern Texas. Because many Hooded Mergansers winter as far north as the lack of ice permits, this duck is one of the first species to appear after ice-out. In many years, they arrive within a few days of open water. I have previously blogged on Hooded Merganser biology, but I thought this photo deserved an additional post.

Sunday, March 11, 2012

Common Redpoll

Until a friend recently asked, I had not given much thought about identifying Common Redpolls from other finches. In Minnesota I suspect the most similar species would be House or Purple finches. See my 2010 post for photos of House and Purple finches. This photo is one of the few Common Redpolls that visited our feeders this winter. The sex is not identifiable in this plumage.

A male Purple Finch does not have fine brown streaks on its sides and the red color is not restricted to the crown. Should be no problem. A female Purple Finch lacks the red crown, and is a bigger bird with a much larger bill.

Male House Finches also do not have the restricted crown patch and both sexes lack the white superciliary stripe. Because of its red breast, a second-year male Common Redpoll may superficially look like a male House Finch, but the redpoll's head is not uniformly red as in the House Finch.

Hope this helps.

Friday, March 9, 2012

Great Blue Heron on Ice

For the second time in the last few years, Great Blue Herons greeted me on the ice at Wells Lake in Rice County, Minnesota.This past Wednesday, 27 birds loafed on the ice. Why don't these birds get hypothermic? I have previously posted on counter current exchanges in birds. In the upper legs, many birds have networks of arteries and veins. The arteries bring warm blood from the bird's body. This warmth is captured by the cool veins flowing back from the bird's extremities. These heat exchanges can be very efficient, leaving relatively little heat to be lost to the ice.

The second heron photograph was not taken on the ice at Wells Lake. Rather, this Florida bird had more sense to take on an early Minnesota spring!

Wednesday, March 7, 2012

Osprey

Ospreys are magnificent raptors. They dive feet first into the water, 99% of their prey consists of fish. As spectacular as their dives are, they only reach depths of about a meter. Thus they take only fish from the shallows or surface. Other prey items have been reported for Ospreys (birds, snakes, voles, squirrels, muskrats, salamanders, and even a small alligator (Pool et al. 2002)) and I once saw one carrying a small mouse over a forest clearing.

Ospreys breeding in Minnesota winter in Central and South American. Poole et al. (2002) calculate an osprey may "fly more than 200,000 kilometers in migration during its 15-to 20-year lifetime." From the 1950s to 1970s, Osprey populations crashed primarily due to pesticide poisoning. Their numbers have rebounded due to pesticide control and an aggressive program of providing Ospreys with artificial nest sites. In some areas, perhaps due to the cutting of old trees, almost all Ospreys use these sites.

I took these photographs a couple of winters ago in southwest Florida. These birds, as many across North America, are tolerant of humans and sometimes allow close approach.


Monday, March 5, 2012

White-fronted Goose

In late February, eBird, in conjunction with the National Oceanic and Atmospheric Administration (NOAA) predicted an early beginning for waterfowl migration due to an unsually "early blast of warm air." Writes eBird, "Snow, Canada, Cackling, Greater White-fronted, and Ross’s Geese should all be on the move with this weather system. Watch for them to potentially move north to staging areas in Nebraska, and possibly to Quebec and points further east. There is also a possibility that some western geese (Cackling, Greater White-fronted, and Ross's) could be displaced eastward with the strong southwesterly flow."

Sure enough, on 25 February 2012, local birders found White-fronted Geese on Wells Lake near Fairibault in Rice County, Minnesota. It took Erika and me three trips to Wells Lake to finally locate the White-fronts. In the upper photo, taken on 3 March, one is clearly visible in the center left of the photo: note the orange-yellow bill and feet, white face patch, and speckled belly. If you look closely, however, you will note two more White-fronted Geese asleep behind the Canada Geese at the far right of the photo. Note the white line below their wings. Several years ago, as you can see below, John H. and I photographed a pair of White-fronted Geese at this same location.

Saturday, March 3, 2012

Green Frog

Last summer in the water feature, we thought we spawned a tiny and timid Loch Ness Monster. We slowly realized the monster is probably a Green Frog, Rana clamitans.
Green Frogs seemed super-abundant in Northfield last summer. Their abundance, no doubt, is related to their laying up to 4000 eggs per summer. The eggs hatch within a week, but the tadpoles overwinter and metamorphose into adults the next summer (MN Department of Natural Resources). I spied them in almost every roadside pond and even in other neighborhood water features. They often rested on the shore, leaping into the water to avoid predators.

Thursday, March 1, 2012

Leopard Frog

Northern Leopard Frogs are found across the northern United States and southern Canada (with the exception of the far west coast). They were abundant, but their populations since the 1970s have declined. The reasons for this decline are obscure, but might involve a combination of "pollution, deforestation, and increasing water acidity" (National Geographic Society). Nevertheless, Leopard Frogs were common last summer in the Carleton College Arboretum.

Why care about Leopard Frogs? Besides the stock answer that they occupy an essential niche of the ecological system, Leopard Frogs produce enzymes that are being studied as cancer drugs for humans. One enzyme, ranpirnase is in clinical trials for lung cancers and another, amphinase, may be effective in combating brain tumors (Wikipedia).