Eastern Screech-Owl

Saturday’s Christmas Bird Count was run despite dire predictions from the weather service. We got about six inches of fluffy snow on Friday night, but the winds were not fierce and the temperatures stayed above zero. We saw a couple of interesting birds. One, the Eastern Screech-Owl was found by others outside our count area. After lunch, we drove over to take a look.

Gray Catbird

This Gray Catbird is an exception to the rule that this species inhabits dense, shrubby vegetation. I found this bird foraging for insects from a Frisbee course basket. I was searching for dragonflies along Carleton College’s Lyman Lakes last June. Catbirds sometimes earn farmers’ ire by consuming fruit. This individual ate small caterpillars, perhaps redeeming its berry-eating reputation.

Gray Catbirds are one of the few birds that regularly eject cowbird eggs from their nests. This ability is learned. Catbirds only destroy cowbird eggs after they learn what their own eggs look like. If cowbirds lay their eggs in the nest before the catbirds, then the catbirds destroy their own eggs! Ornithologists do not know if, in subsequent years, older catbirds have to relearn the appearance their eggs (Smith et al. 2011).

Great Crested Flycatcher

Great Crested Flycatchers are another species that is probaby more common now than before the great forests of eastern North America were destroyed. Forest fragmentation caused increases in woodlots and woodland edges favored by this flycatcher. I took this photograph last summer in Erika’s garden.

This species is the only flycatcher that nests in cavities, either natural, excavated by woodpeckers, or human built. Great Crested Flycatchers are famous for often using shed snakeskin in their nest, presumably to discourage potential predators. Other items that look like snakeskin, like plastic wrappers, are occasionally used instead (Miller and Lanyon 2014).

Common Baskettail

Flying dragonflies are always a challenge to photograph. I captured this Common Baskettail on 11 June 2016 over the Lyman Lakes of Carleton College. This baskettail was making patrolling flights back and forth along the edge of the lake.

Common Baskettails are often abundant across most of eastern North America. The are found over almost any body of quiet water. Although not present on all individuals, the dark spotted hindwings are good field marks for identifying this species.

Blue and Green-winged Teal

On 24 August 2016, I found a large flock of Blue-winged Teal at the Dennison, Minnesota, sewage treatment ponds. The ducks circled the facility as I took photos. To my surprise, when I got home and worked on the images, I discovered that one of the ducks was not a Blue-winged Teal. The lowest bird in the center of the photo is actually a Green-winged Teal.

Eastern Pondhawk

Eastern Pondhawks from 2016. The first two photos, both taken on 1 June, are from Carleton College’s Lower Arboretum here in Rice County, Minnesota. The first one is male, the second, female.

The third photo is of an immature male taken at the Savannah National Wildlife Refuge in Jasper County, South Carolina on 24 March. The last image is from St Marks National Wildlife Refuge, Wakulla County, Florida on 23 March.

Considering their wide range, almost all of the eastern United States east of the Rockies, I am surprised that local, isolated populations have not evolved into distinct species. On the other hand, Eastern Pondhawks are abundant and not very particular in their habitat selection. Almost any slow moving or still water will suffice.

Snow Goose

Yesterday, 5 December, Erika and I found two Snow Geese at the Jefferson Parkway Wetlands in eastern Northfield. These birds were first reported by Gerry Hoekstra on 29 November, but had not been seen since. Gerry returned later in the day and found a third, young Snow Goose.

White and “blue” Snow Geese are color morphs of a single species. Only in 1983 did ornithologists figure out this situation. One gene controls this color difference. The dark gene is incompletely dominant over the white one.  The dark gene is unequally distributed across the Snow Goose’s range. Most dark-morph geese breed and winter in central areas of North America. Finally, ornithologists discovered that the two morphs’ ranges did not overlap until about 70 years ago (Mobray et al. 2000).

Chestnut-sided Warbler

I banded this Chestnut-sided Warbler this spring in Northfield. In Audubon’s time, this species was hardly ever encountered (Byers et al. 2013). An inhabitant of forest edges and secondary growth, this warbler benefited from humans’clear-cutting the continent’s old growth forests. Now it can be the most abundant breeding warbler in early succession woodlands.

Common Green Darner

A perched Common Green Darner can be hard to see, even when you are looking right at one. This female, from last summer, was resting in the Whitetail Woods County Park in Dakota County, Minnesota.

As its name suggests, this dragonfly is common across most of North America. The species migrates south into Central America. They arrive in the north well before local dragonflies have emerged. Their migration is cued by warm fronts (DragonflyID app). After breeding, they head south, sometimes in large numbers. Common Green Darners are an important component of many bird diets, including those of American Kestrels, nighthawks, and Purple Martins.

Purple Martin

I photographed this female Purple Martin on 13 June 2016, at Lake Byllesby Regional Park, Dakota County, Minnesota. Martins in Canada and the northern United States have a lot going against them. They depend on flying insects. Cold weather kills their insect prey, which, in turn, can wipe out local martin populations. By out-competing nesting martins, introduced starlings and House Sparrows can also wipe out these swallows.