Friday, June 24, 2016

Chalk-fronted Corporal and Frosted Whiteface


On 21 June 2016, Erika and I took a long walk in the Lebanon Hills Regional Park in Dakota County, Minnesota. The numbers and diversity of dragonflies were exceptional. Hundreds of Chalk-fronted Corporals greeted us. This ode gets the name from the two, gray chevrons on top of their thorax. These bars look like a corporal’s insignia.
The less mature Chalk-fronts did not show their rank as well as the adult male corporals. As I looked at them, I realized that immatures might be hard to tell from Frosted Whiteface. Understand, I had Frosted Whiteface on my mind. I had never seen one, but had vowed to try to find this species in 2016. So I had studied up on them, but expected to find them another day and further north in Minnesota.
I started looking at the corporals more closely. Towards the end of our hike, without a doubt, I found my Frosted Whiteface. In the photograph above, despite a superficial similarity to immature Chalk-fronted Corporals, you can see the “frosty” pruinosity on the top of the abdomen. They white marks on the wings may also be significant—and look at the white mouthparts! This first Frosted Whiteface is a male.
Nearby flew several other whitefaces that were much brighter than the first. These are probably immature males. Frosted Whiteface range across the northeastern United States and southeastern Canada. Minnesota is as far west as they are normally found. These individuals are the first ever reported from Dakota County.

Thursday, June 23, 2016

Fish Crow

I have written that I expect Fish Crows to be found in Minnesota. These small crows are expanding their range from coastal areas of the Southeast. They are adapting successfully to urban settings (McGowan 2001).

The problem is that Fish and American crows are very similar. We took the upper photo of a Fish Crow in the St. Marks National Wildlife Refuge last March. The lower photo is of the larger American Crow. In the field, calls are the only reliable difference. McGowan writes, “the Fish Crow sounds like an American Crow with a bad cold.” Here in Minnesota, however, I have heard American Crows that sound like Fish Crows. I have even heard Minnesota birds give what sounded like a Fish Crow’s double-noted “Uh-uh” call. One difficulty is that young American Crows often give odd calls.

Tuesday, June 21, 2016

Common Green Darner

Mead writes that two populations of Common Green Darners exist in Minnesota—one resident, the other migratory. The residents overwinter and emerge in the spring. The migrants leave in late summer. Their offspring return the next year. We found this darner in the Carleton College arboretum on 19 June 2016.

Photographing dragonflies takes manual focusing. These insects are long-gone by the time the automatic focus kicks in. Nor does automatic focus often work on perched individuals. The camera tends to lock on areas behind the wings or the larger nearby twigs.

Monday, June 20, 2016

Northern Cardinal

Even casual birders are familiar with Cardinals. This female perched in front of us at Florida’s St. Marks National Wildlife Refuge last March. The male sang in our backyard in Northfield this spring. Since the 1800s, Northern Cardinals have moved northward, assisted by global warming, urbanization, and bird feeders.

The red color in both male and female cardinals is due to carotenoid pigments in the birds’ diet. The color signals mate quality. Bright males have higher reproductive success than duller ones. Bright colors in the male and in the underwing of the female are correlated with parental care—bright birds are the best providers for their young (Halkin and Linville 1999).

Sunday, June 19, 2016

Amber-winged Spreadwing


I am on a roll. A second new county record in as many days. Yesterday Erika and I made a quick stop at the Carpenter Nature Center and photographed this Amber-winged Spreadwing. According to Odonata Central, our record is the first for Washington County, Minnesota.

The amber-washed wings and the long “pinchers” at the end of the abdomen are diagnostic for this species. This male is my first. Previously we photographed a female in Erika’s garden. Amber-winged Spreadwings are found across northeastern North America, west to Minnesota, Iowa, and eastern Kansas and Oklahoma.

Saturday, June 18, 2016

Blue-eyed Darner

I photographed this Blue-eyed Darner in Northfield on 17 June 2016. Darners are damned difficult to photograph. Way too much darting back and forth for automatic focus. It took 90 minutes and 63 attempts to get one good picture. Most of my efforts look more like the bottom picture.

This record is possibly the 5th from Minnesota; definitely the first from Rice Co. Scott King discovered these dragonflies yesterday. About six flew about a small catchment pool on the edge of the St. Olaf campus. They were swooped upon by Tree and Barn swallows and Red-winged Blackbirds—I can’t imagine the dragonflies will last long.

Friday, June 17, 2016

Black-throated Green Warbler

This spring I really had only one migratory warbler wave, on 24 May. Among the birds banded, was this female Black-throated Green Warbler. This warbler is an abundant breeder across much of northern and eastern North America. That I do not band more of these birds is a bit odd.

The Black-throated Green Warbler’s call is distinctive, usually a “lispy, dreamy" zee zee zee zee zoo zee, with the zees at the same pitch, and the zoo lower (Peterson). Listen. The males tend to sing persistently.  One male sang 466 songs in an hour (Morse and Poole 2006).

Thursday, June 16, 2016

Common Buckeye

You’ve heard of folks finding Rembrandts in their attics? Last Sunday, in the St. Olaf Natural Lands, I found a Bob Ross original on a Common Buckeye butterfly. See the silhouettes of the happy White Pines against evening thunder clouds?  See my previous post for more information about this amazing butterfly.

Tuesday, June 14, 2016

Anhinga

Anhingas spend a lot of time under water. They have dense bones and wettable feathers to facilitate underwater travel. Being under water so long, they face thermal challenges. They spend hours warming themselves, like this one at Florida's St. Marks National Wildlife Refuge. In fact, this dependence on solar radiation limits the Anhinga to the coastal plain of the southeast, and on south through coastal Mexico and South America (Frederick and Siegel-Causey 2000). See my 2011 post for more information on Anhingas.

Monday, June 13, 2016

Red-breasted Merganser

We photographed this handsome, hen Red-breasted Merganser on 23 March 3026 in Florida's St. Marks National Wildlife Refuge. This duck can be hard to differentiate from Common Mergansers—the brown head and the white breast are not as abruptly contrasting and the bills are thinner in the Red-breasted. Compare this hen to a female Common Merganser in my 2011 post.

Both mergansers occur during migration in Minnesota. Red-breasted Mergansers winter along the coast of North America, while Common Mergansers do not venture into the southeastern states. On the other hand, Red-breasted Mergansers breed further north than do Commons. One consequence of these differences is that relatively little is known about Red-breasted Merganser biology (Craik et al. 2015).