Twelve-spotted Skimmer 2

Readers may recall my 10 June 2011 blog lament that I had yet to see a male Twelve-spotted Skimmer.  That deficiency is now remedied. Several appeared in Erika's garden in late June. As you can see, the male is a striking dragonfly. Depending on which spots you count, this skimmer is also known as the Ten-spotted Skipper.

Twelve-spotted Skimmers hunt from perches, to which they will often return, even after the dragonflies are disturbed.  The skimmer below seemed fond of Erika's Astilbe, despite the flower's relatively low profile in the garden. This skimmer eats a wide variety of flying insects (mosquitoes, flies, butterflies, moths, mayflies, and flying ants).

The last photo in this series of of a female Twelve-spotted Skimmer.The photograph perplexes me--I thought it was a male when I took the picture--but no white spots are evident.  This skimmer is found in appropriate habitat from southern Canada through most of the United States.

Hackberry Emperor

This Hackberry Emperor warmed itself on the hot side of our house.  Erika's garden probably did not attract it, as this species specializes on Hackberry leaves and sap.  They also drink from dung and carrion.   (I suspect that urine may attract a host of butterfly species, but Erika has not given me leave to experiment in her garden.)  Hackberry Emperors also take human sweat (Bugguide.com). This source describes this butterfly as "subtly beautiful." The species is found across the lower 48 states, from southern Canada through northern Mexico. In Minnesota  it is restricted to the southern portion of the state ( Ecobirder).

Cassin's vs. Purple Finch

A large flock of Cassin's Finches were the highlight of our friend's Missoula feeder. Identifying Cassin's Finches turns out to be more complex than I first thought.  Even a Cornell website concludes that separating Cassin's and Purple finches can be extremely difficult. I needed all of my identification guides to ferret out the differences, with no one guide giving definitive advice.

The two photos above are of male Cassin's Finches.  The photo immediately below is of a male Purple Finch.  The salient field marks of male Cassin's Finch are as follows:

1.) The red tends to be much brighter than the rest of the head, giving it an almost redpoll appearance.  Purple Finch heads are more uniformly colored.

2.) Cassin Finch bills tend to be straigher and sharper, more like a siskin.  Compare the first and third photographs.  The top of the upper bill of the Cassin's finch tends to be straighter, at least until the very tip.  In contrast, the Purple Finch's bill is shorter and tends to be uniformly curved on the top.

3.) The lower flanks of the Cassin's Finch have fine brown streaks.  What streaks there are on a Purple Finch tend to be blurrier and reddish.

4.) Male and female Cassin's Finches tend to have a thin white eye-ring, absent in Purple Finches.

5.) My photos indicate that Cassin's Finches' breasts have a slightly different red hue.

Other field marks mentioned in various field guides, but they do not seem to be evident in my photographs.  Peterson's Western Birds indicates that the Purple Finch's nape is reddish.  My photo shows a Purple Finch with a brownish nape.  On the other hand, Sibley's Birds of North America does not depict the distinct brownish malar streaks on male Cassin's Finches, while Peterson's illustration does.

The next two photographs are of female finches, first Cassin's and, finally, Purple.

1.) The bills sort out similar to the males'--pointy and siskin-like in the Cassin's, stubbier and chunkier in the Purple.

2.) The streaks on the underparts differ. The Cassin's streaks are crisp and dark.  The Purple's streaks are fuzzier and more diffuse.

3.) Again, Cassin's Finches tend to show a thin, white eye-ring.

Some field guides suggest that the facial pattern is less distinct on the female Cassin's Finch.  My photos shed some doubt on this mark as being really useful.  The Cassin's Finches we saw appeared to have more white around their eyes. House Finches are also similar to Cassin's and Purple finches, and were also present at the Missoula feeder.  Previously I have blogged on the identification of Purple and House finches.

Minnesota birders may wonder why one would blog at such length on this subject.  The closest Cassin's finches breed to Minnesota is in the Black Hills of South Dakota. They breed in the Rocky Mountains.  Minnesota birders should take note. We have at least one record of a Cassin's Finch, a bird found at a Duluth feeder in November 1986 (Eckert, A Birder's Guide to Minnesota Birds).

Red Crossbill

A pair of Red Crossbills also fed at the Missoula bird feeder.  I was excited as, despite my banding many Red Crossbills,  I have mysteriously never photographed one. These photos are of the male, the female escaped my lens.  The curiously crossed bill is adapted as a conifer cone opener.

Birders have long recognized that Red Crossbills come in different sizes. One winter in Aberdeen I had a single flock of large and small crossbills visiting our feeder.  The size correlates with the size of the cones on which the birds feed.  Crossbills are nomadic and breed when a flock finds plenty the correct sized conifer cones.

Ornithologists next discovered that the different sized crossbills have distinct calls.  Furthermore, even when they breed in the same forest, birds with different calls do not interbreed.  Therefore we may have at least eight different species of red crossbills in North America!  Sibley's website discusses this situation and provides some interesting links.

Evening Grosbeak

After the Badlands, the next stop on our western expedition was Missoula, Montana.   We visited friends who keep a bird feeder.  We were greeted by a pair of Evening Grosbeaks, old friends from the Minnesota North Woods.  These grosbeaks breed across Canada and the northernmost United States,  then south through the Rocky Mountians as far as southern Mexico.

Evening Grosbeaks are irruptive migrants, in the United States usually appearing in two-year cycles. Relatively recently Evening Grosbeaks have expanded eastward.  One hypothesis is that this range change is due to the planting of Box Elders in eastern cities.  Box Elder seeds are often abundant all winter, providing the grosbeaks with plenty of food.  Grosbeaks also favor Spruce Budworms, and the birds may have expanded their range after particularly big budworm outbreaks (Gillihan and Byers 2001). I have banded Evening Grosbeaks in northeastern South Dakota and saw them during the winter as a boy in Virginia.  I am told that recently grosbeaks are seldom seen in the southeast.  I am surprised that I have not seen an Evening Grosbeak in Rice County.

My mentor Roxie Laybourne once showed me a gynandromorph Evening Grosbeak.  This bird was half male and half female.  It was yellowish on the right side, gray on the left, with a sharp line of demarcation between the two.  Furthermore, the ovary was on the left side and the testis on the right.  In other words, a testis lay under the female-plumage and an ovary under the right.  This specimen and photographs of other gynandromorphs can be seen by clicking here.  I have also seen a specimen of a gynandromorph  Great-tailed Grackle, large on one half, small on the other.  I have no idea how that bird survived in the wild.

Orchard Oriole

Orchard Orioles breed east of the Rocky Mountains, with highest densities in the northern Great Plains and the Southeast.  In Minnesota they are uncommon, with most seen in the southwest (Eckert 2002).  Erika and I found this second-year male on the Carleton College campus on 24 June 2011. (First year males are greenish like the females, but have black throats.) Orchard Orioles nest late in the spring and raise only one brood.  Where they are common, Orchard Orioles breed in loose colonies, with many nests in a single tree. They return to their Central American wintering range as early as mid-July (Scharf and Kren 2010).  This early departure results in few sightings during the fall migration.

Ebony Jewelwing

Upon our return from Olympia, on 24 June 2011, Erika and I strolled by the flooding Cannon River in the Carleton College Arboretum.  We happened upon this exquisite Ebony Jewelwing, a damselfly of eastern North America.  True to the text in bugguide.net, this jewelwing inhabits wooded stream-sides.  The adults perch on low shrubs lit by openings in the forest canopy.  We found this female to be quite wary, but it never fluttered far, landing repeatedly on nearby sunny leaves, until finally disappearing into the dense shrubbery.

Prairie Dogs and Burrowing Owls

One of the many birds we missed during our western jaunt was the Burrowing Owl.  (The photo below is of an owl taken in South Dakota a few years ago.) Often finding Burrowing Owls is not difficult if you scan Black-tailed Prairie Dog colonies.  We found the rodents in the Badlands National Park but came up empty in the owl department.

Prairie dogs are extremely susceptible to plague. Plague, of course, can be transmitted to people who come in contact with prairie dog fleas.  So rolling around in prairie dog towns is not advised, especially if you do not often bathe.

Black-tailed Prairie Dogs are despised by many ranchers who go to great lengths to eradicate them. Ranchers could control prairie dogs by keeping their range-land in excellent condition, since the rodents prefer poor quality range-land.  In any case, as populations declined, the Fish and Wildlife Service created a political maelstrom by suggesting putting prairie dogs on the Endangered Species Act Candidate Species List.  The agency capitulated in August 2004.

Burrowing Owls nest and roost in empty prairie dog burrows.  Zuni Indians called this owl the “priest of the prairie dogs."  (This quote and much of the owl data are from Haug et al. 1993.) Burrowing Owls are out in both daylight and during the night.  Fortunately for the owls, they are not restricted to prairie dog burrows. Also utilized are burrows of ground squirrels, badgers, marmots, skunks, armadillos, kangaroo rats, and tortoises. They rarely dig their own burrows. Burrowing Owls have an interesting distribution--western North America south through Mexico and Central America, but also Florida, the Bahamas, western Cuba, and Hispaniola.  Isolated populations also occur in South America. Burrowing Owl populations are declining across most of its range. Being hit by cars is the major cause of mortality because the owls often feed on roads at night.

Lark Sparrow

Another good birding location in South Dakota's Badlands National Park is the Cedar Pass nature trail.  Uncharacteristically, we did not observe many birds during our visit.  An exception was a tame Lark Sparrow, a species I previously tried to photograph with relative lack of success.

Erika commented, "This Lark Sparrow is really posing!"  The sparrow strutted, holding its head high. I learned from Martin and Parrish (2000) that, unlike other songbirds, Lark Sparrows perform "turkey-like strutting with tail upright, flashing white tail spots, and wings dropped to the ground." Females often use nests abandoned by other species.

Lark Sparrows breed across much of the western United States.  Formerly this sparrow also bred to the Atlantic coast, but its breeding range has been receding--now it is found east only across Minnesota and Iowa.  Hypotheses for this retreat include the reforestation of eastern fields and the spread of urbanization. A Lark Sparrow was one of the first rare birds I ever recorded--a bird at our Virginia bird feeder.  Most years I see a few in Minnesota.  They become common in western South Dakota.

Western Birds

Where does western North America begin?  Even though all three of the birds in this post can be found in Minnesota, they are more associated with the west.  As a imprecise rule of thumb, the West begins at the 100th meridian.  In central South Dakota, that line runs just east of the Missouri River. On our recent road-trip we took a short detour through the Badlands National Park in western South Dakota.

Western Meadowlarks greeted us at the park entrance.  In most of South Dakota, unlike in Minnesota, identifying Eastern from Western meadowlarks is not too much of a challenge--Western Meadowlarks are usually the only species present.  Identification was confirmed by the Western Meadlowlark's loud, gurgling, "Have you planted your wheat yet?"  This call is quite unlike the Eastern's lazy "Sweet Sue" whistle.

An excellent location to find birds in the Badlands National Park is at the park headquarters. Western Kingbirds hawked for insects over the parking lot.  Notice the white edge to the outer tail feathers. 

Mountain Bluebirds are more restricted to western North America than are the two previous species.  But even they occasionally stray east to Minnesota.  This individual must have been nesting nearby, as evidenced by the grub it grabbed from the lawn in back of the park headquarters.