Monday, January 30, 2017

Eastern Forktail

A collection of Eastern Forktail photos from 2016. The first is an immature female, the second a mature female and the last, a mature male. This damselfly is abundant across much of eastern North America. They are apparently monogamous. After being fertilized by a single male, a female may lay more than a thousand eggs (DragonflyID).

Saturday, January 28, 2017

White-breasted Nuthatch

During Wednesday’s snow storm, this White-breasted Nuthatch camped out at the feeder. The bird almost appeared to be sleeping, unwilling to leave the food source. Birds also stay still when predators are present, but this bird appears to have half-open eyes.

Before the advent of DNA research, nuthatches were thought to be closely related to chickadees. But genetic studies indicate they are actually closely allied with creepers, wrens, and gnatcatchers. Within their family, White-breasted Nuthatches do not seem closely related to other nuthatch species (Grubb and Pravosudov 2008).

Wednesday, January 25, 2017

Red-tailed Hawk

Yesterday, on 24 January 2016, Erika and I encountered a relatively pale Red-tailed Hawk. The raptor perched high in a tree between the Carleton College campus and the city of Northfield. Quickly three American Crows appeared and began harassing the hawk. 

Why do passerines mob hawks? Two years ago, I blogged about Blue Jays mobbing a Red-shouldered Hawk. I wrote, “Several hypotheses exist for why small birds mob predators.  Mobbing alerts nearby birds of the nearby predator. The hawk probably has trouble keying in on a single mobber, thus there may be safety in numbers. Mobbing may also drive a dangerous predator away.” 

Sunday, January 22, 2017

Icy Woods

Icc-covered trees last Wednesday at Big Woods State Park. A pleasant stroll during our January thaw, but few birds ventured forth.

Friday, January 20, 2017

Mourning Dove

On 19 January 2017, a lonely Mourning Dove landed below our snowy bird feeders. These doves occasionally attempt to winter in Minnesota. Sometimes you can find flocks of a couple of dozen or more. Eckert considers them to be uncommon and local during Minnesota winters.

More interesting to me is the molt on this bird’s shoulder.  To see these pin feathers, you may have to enlarge the image.  The shoulder feathers may be being replaced after some sort of injury.

Another explanation for this molt is possible. Mourning Doves can molt all year, although they usually do not molt in December or January. Look at the feather tips at the end of the wing.  If you look closely, you may also notice that the outermost primaries are brown rather than gray. This brown color means that these feathers are unmolted, while the others are fresh. These doves go through a prebasic molt (into winter plumage), and they lose their outermost primaries last (Otis et al. 2008). Sometimes this molt may pause, so perhaps this bird is just finishing its fall molt.

Wednesday, January 18, 2017

American Redstart

American Redstarts from last summer. The first image is of a female. Notice the complete lack of black on her face and her pale, yellow flanks. First-year males have varying amounts of black on their heads and much brighter yellowish-orange flanks. Males do not acquire their striking black and orange plumage until their second year.
American Redstarts breed across Canadian forests, south almost to the Gulf of Mexico. They winter in central Mexico south to northern South America. They are often abundant and easy to identify.

Monday, January 16, 2017

Hooded Merganser

On 8 July 2016, Erika and I found a young Hooded Merganser at the River Bend Nature Center in Faribault, Minnesota. You can tell the age by the dark eye. Adults sport yellow eyes. The species breeds across most of the United States and southern Canada, wintering in the southern half of their range.
Hooded Mergansers leave their nest boxes within a day of hatching. The young eat a variety of aquatic insects. They appear to be especially fond of dragonfly nymphs.
Young birds feed themselves from their first day out of the nest. Only the females care for the young. The hens may remain with their broods for up to a month. Some fledglings move north, up to 700 km, in the fall, before heading back south to their winter range (Dugger el al. 2009).

Saturday, January 14, 2017

Pileated Woodpecker

Pileated Woodpeckers are our favorite woodpecker visitors to our winter feeder. Numbers of this crown-sized species depend on the presence of large, dead or deteriorating, trees. The birds use these trees for nesting and roosting. The woodpeckers suffer when forests are clearcut or if older trees are removed. Pairs defend their territory all year. Individuals do not abandon territories even if mates die (Bull and Jackson 2011).

Thursday, January 12, 2017

Northern (Yellow-shafted) Flicker

This Northern Flicker was forced off the suet feeder by an aggressive Red-bellied Woodpecker. Flickers are, in fact, woodpeckers that often feed on the ground. In the summer, they gorge on ants. In the winter, they feed like other woodpeckers, and even occasionally on fruit.

The eastern Yellow-shafted Flicker is the expected race here in Minnesota. You may recall that we found an intergrade bird, showing characteristics of a Yellow-shafted and a Red-shafted flicker during our recent Christmas Bird Count. Unlike the previous flicker, this one shows tan, not gray, sides to its face and yellow shafts in the tail—clearly a male Yellow-shafted Flicker. The hybrid zone between the races runs Ron the Texas panhandle north through the western Dakotas and into southwestern Canada.

Tuesday, January 10, 2017

Hairy vs Downy Woodpecker

The bird feeder this second week of January is host to a plethora of Downy and Hairy woodpeckers (and little else). How to identify these species?  When both species can be directly compared, like in the middle photo, the Hairy Woodpecker’s larger bulk is obvious. Also compare the bill size. The Hairy’s bill is definitely larger. (Notice that the Hairy Woodpecker in the first photo is banded.)
Here are two not so reliable field marks. In the center photo, notice the black marks on the Downy Woodpecker’s white outer tail feathers. These spots are never present on Hairy Woodpeckers. But notice the white outer tail feathers on the Downy Woodpecker in the bottom photo. Not all Downy Woodpeckers have those spots. Notice also that the red napes on both species can be continuous, and not in two patches, which sometimes occurs in both species.

Despite their similarities, DNA studies indicate these two woodpeckers are not closely related. They remain in the same genus, but Downy Woodpeckers are most closely allied to western Nuttall’s and Ladder-backed woodpeckers. Hairy Woodpeckers are more closely related to Red-cockaded, White-headed and Arizona woodpeckers (Morin in Western Woodlands).

Saturday, January 7, 2017

Brown-headed Cowbird

On 10 May 2016, I photographed a male (above) and female (below) Brown-headed Cowbirds. Cowbirds are brood parasites. They lay their eggs in other birds’ nests. Over 220 host species have been cataloged. The pressure on the hosts a be substantial. Female cowbirds can lay up to 40 eggs per season and the cowbirds wander widely (Lowther 1993).

Cowbirds were originally found only in short-grass prairies, They ate insects disturbed by bison herds. With the ecological agricultural and urban homogenization of North America, Brown-headed Cowbirds are now found from coast to coast in southern Canada, the United States and Mexico.

Thursday, January 5, 2017

Tufted Titmouse

You don’t see too many Tufted Titmice in our part of Minnesota. Yesterday Erika and I counted birds for the Red Wing, Minnesota, Christmas Bird Count. We knew these birds hang out at a Frontenac feeder, and we did see one at that location. This photo is of a second bird we spotted a few miles west of Frontenac. Temperatures were at zero, and the wind chill was -23. No wonder the titmouse seems a bit fluffed up. Titmice in Minnesota are kind of surprising. This species tends to be sedentary. During the last 70 years, the range of titmice has expended northward. This movement may be due to post-breeding dispersal, global warming (although this phenomenon was in scant evidence on this day), and/or bird local feeders.

Monday, January 2, 2017

House Finch

House Finches are now among the most common North American birds. Once they were restricted to the desert Southwest. The history of a captive flock’s liberation in New York and subsequent spread west is well known (and can be read about elsewhere in this blog).

I was not so aware of the House Finch’s expanding western range. There some birds undergo short, seasonal movements. After arriving to a new area, in snowy winters they often move along mountain valleys until they get to cities. They stay in the towns if they encounter sufficient bird feeders and relatively little snow. Within a decade, populations become year-round residents (Badyaev et al. 2012).

Sunday, January 1, 2017

New Year 2017

Happy New Year. January first, and every bird is new for the year—even this Downy Woodpecker! At 262 species, last year was not my best, but nor was it my worst. As is the case every New Year’s Day, I have high hopes for the upcoming year-list. Hope all our adventures this year are a grand success.