Plains vs. Midland Clubtail

Scott King and I were unsuccessful in our search for snaketails on our expedition to the Cannon River Wilderness area last Tuesday. We did encounter two Midland Clubtails in a wheel position—the male above almost covering the female’s face as he guards her against fertilization by other males; the female collecting sperm from the male. Scott commented that clubtails usually were more desecrate and were not so often seen in reproductive mode. 

You may recall that a few posts ago I complained about how Midland Clubtains in our part of Minnesota are quite variable in their abdomen patterns. In our region, this diversity can make them difficult to separate from Plains Clubtails. Compare the Midland Clubtail (second photo) and the Plains Clubtail (third photo) that we also found on Tuesday. Scott patiently explained to me the critical differences between the two species. Note the underside of the third abdominal segment is white in the Plains Clubtail—it is usually yellow in the Midland, which tends to have narrower colored bands on the sides of its thorax. This last field mark is not so obvious in my photos.

Cobra Clubtail

Compared to other local clubtails, the Cobra is very black. Note also the dark bar on the face. Several years ago, when I saw my first specimen, I wondered about the name. Not so when Scott King and I found this one on the road leading into the Cannon Valley Wilderness Area south of Northfield. When the dragonfly raised its abdomen, it did give the impression of a hooded snake.

Cobra Clubtails prefer sandy-bottomed streams with a slow to moderate current (Paulson 2011). The Cannon River in flood stage did not seem to deter these individuals.

Inca Dove

Mueller and Mueller (2014) write, “During the day...[Inca Doves] alternate feeding, loafing, and sunning.” Last February, this Inca Dove, from just north of Edinburg, Texas, seems to be partaking in the latter two behaviors. Field marks for this species include the long tail and the scaly-looking body.

Inca Doves are found in the southwestern United State south to northern Central America. In the past 100 years, the species has spread both north and south. Originally birds of arid land, they have readily adapted to suburban habitats, taking advantage of water and bird feeders. See also my 2012 post on Inca Doves.

Common Ground-Dove

Apparently I have never posted anything about Common Ground-Doves. My previous photographs, taken in Florida and Texas, have not been stellar. This photo, taken this February at a feeder near Edinburg, Texas, is the best of the lot.

This dove is one of the smallest in North America. It is found across the southern United States through northern South America. It loves scrubland, but also is found in suburban habitats. Numbers of North American Common Ground-Doves are declining. Habitat loss to human development and fire suppression and resultant loss of early-succession habitat have been suggested as reasons for this drop in numbers (Bowman 2002).

Emerald Spreadwing

On Tuesday, 14 July 2014, Scott King and I explored the River Bend Nature Center near Faribault, Minnesota. Scott pointed out an Emerald Spreadwing in the tall grass near a pond. This damselfly is common enough here, but one for which I had searched in vain.

This species has a wide distribution across northern North America, Asia, and Europe. It is not common in Britain, and where, until recently, it was thought to be extinct. There it is known as the Scarce Emerald Damselfly. No other damselfly has such a wide range. Here in the Upper Midwest, Emerald Spreadwings are found in temporary woodland ponds that lack predators. They have a life cycle with many stages. These emeralds overwinter as eggs, which are deposited into live stems of various marsh plants and into willows, sometimes high above the ground. Some eggs can withstand temperatures below -4 degrees F (DuBois 2005; Paulson 2011).

Sedge Wren

I encountered a pair of Sedge Wrens on 22 June 2014 in the Carleton College arboretum. Sedge Wrens are found in the American Upper Midwest and also occurs in Central and South America. I have previously blogged about their curious North American breeding distribution—they have two breeding seasons in this region, one in May and June in the north, and a second in July through September further south.

Sedge Wrens inhabit ephemeral grasslands. Drought and flooding cause these changes. Human created grazing and harvesting add to the transitory nature of Sedge Wren breeding habitat. The result is high mortality and low site tenactiy among the wrens (Herkert et al. 2001).

Yellow-throated Warbler

These photographs are not the most stellar of a Yellow-throated Warbler, but do show why colonial ornithologist Mark Catesby (1682-1749) called it the Yellow-throated Creeper. This and two other Yellow-throated Warblers worked their way through the high canopy of trees around the gift shop parking lot at Whitewater State Park in southeastern Minnesota on 21 June 2014. Little is known about Yellow-throated Warbler breeding biology because of its treetop habitat.

About a half-dozen records have been reported in Minnesota this year for this denizen of the American Southeast. For unknown reasons, this warbler’s range shrunk in the early 1900s. Now the breeding range is again expanding north (McKay and Hall 2012).

Henslow’s Sparrow

This Henslow’s Sparrow, which Erika and I found in Carleton College’s restored prairie on 20 June 2014. This bird is a bit odd, since Henslow’s Sparrows are supposed to have ochre-washed breasts. Nevertheless, the wing color and the sides of the face are what you would expect of a Henslow’s. The bird was also singing a perfect rendition of a Henslow’s Sparrow’s song, described in Herket et al. (2002) as a “feeble hiccup.”

Henslow’s Sparrows have declined during the last 50 years. In the last 30 years, populations have declined by about 7.5% annually, the biggest drop for any grassland bird in North America (Herket et al. 2002). The loss and degradation of our native prairies seems to be responsible. It is remarkable and heartwarming that Henslow’s Sparrows have returned to the Carleton prairie. Restoration of this tallgrass prairie began in 1978. Plants are usually from local sources and maintained by regular controlled burns. Seeds from these forbs are being used to restore other Minnesota prairies. Carleton’s goal is an 140-acre grassland.

P.S.: Doug Johnson writes "You mentioned that Henslow's have been declining dramatically. That was true until CRP took hold. Now BBS indices have about returned to early levels. What HAS happened is that they shifted their range from eastern prairies to midwestern grasslands, largely I believe due to CRP.(http://www.fwspubs.org/doi/suppl/10.3996/nafa.79.0001/suppl_file/appendix+a.pdf) Hate to see what will happen as CRP continues to fade from the landscape.”

Pelicans and Cormorant

On 18 May 2014, John Holden and I encountered a Double-crested Cormorant that seemed to be conducting a chorus of silent American White Pelicans. All but the pelican on the far left appeared to be following the gaze of their conductor. “Why do cormorants hold their wings out like that?” asked John. Like many a professor, I answered and then verified my reply later. Turns out that cormorants have relativelty little preening oil with which to water-proof their feathers. To keep dry, cormorants have to hang their feathers out to dry. Allaboutbirds.com continues, “though this seems like a problem for a bird that spends its life in water, wet feathers probably make it easier for cormorants to hunt underwater with agility and speed.”

The pelicans, who were really not paying much attention to the cormorant, performed various maintenance behaviors. It looks like a pelican has to be an adept acrobat to scratch its neck, all the while standing on one leg and not falling forward from the weight of its bill. The horn on the White Pelican’s bill, by the way, is present only during breeding season. The horn is present on both sexes and is shed after egg laying. As I have written previously, the exact function of the horn is unknown.

Midland Clubtail

I photographed these Midland Clubtails on 8 June 2014 in the Carleton College arboretum.  I indicated in my last post that I have been finding clubtail identification to be challenging. For one thing, Midland Clubtails in our part of Minnesota tend to be quite variable—our population is in a blend zone between a western and eastern subspecies, Gomphus fraternus fraternus and Gomphus fraternus manitobanus. Most our our Midland Clubtails have a yellow triangle on the top of their 8th abdominal segment. The 9th segment is variably marked, sometimes strongly yellow, other times dusky, and can be totally black.

Another key for identification is the thin yellow or green line across the sides of their thorax. I have previously blogged about Midland Clubtails. This species is a voracious predator that often consumes other dragonflies. This clubtail often perches on sandy trails and roads.