Friday, September 19, 2014

Variegated Meadowhawk

Last Sunday at the Valley Grove Prairie in nearby Rice County, Minnesota, the air was full of dragonflies—mostly Common Green Darners, but also Variegated Meadowhawks like this one. I was struck by its beauty and that it looked different from others I have seen—the blue thoracic stripe seemed unique.

I was confident of my identification (for once), because of the blue-gray “portholes” along the sides of the abdomen. Scott King assures me that this stripe is the mark of a young male, and that the blue will fade, leaving only the yellow spot at the bottom of the stripe. In April 2012, I posted a photograph of an adult male and in September 2011 I explained why one tends to see immature Variegated Meadowhawks in the fall, but adults in the spring.

Thursday, September 18, 2014

Juniper Titmouse

The fourth titmouse species we listed during our winter trip was this Juniper Titmouse.  My photos are poor, the titmice did not pose very still for me, and these are the best I got. I will try to improve upon them the next time I am in the Southwest.

I lacked a photograph of the species, since, when I took photos of them before, they were of the Oak Titmosue, found in oak woodlands of the Pacific slope of California. Juniper Titmice are found in juniper and pinion-juniper woodlands in the interior of the Southwest. Recently the two populations, previously called Plain Titmice, have been declared to be separate species. 

Both species mate for life, and neither forms flocks as do other titmice. Both sexes hold year-round territories. They cache food, which is surprising in a non-flocking species. Males sing all year, though most intensely in the spring, and ususally defend their territories against other bird species (Cicero 2000).

Wednesday, September 17, 2014

Red-backed Junco

Also at the feeders at the Randall Davey Audubon Center in Santa Fe, New Mexico, in March 2014 were several Gray-headed Juncos. Currently ornithologists recognize 15 races of the Dark-eyed Junco, including this one. These races used to be considered to be six species, but they interbreed where their ranges overlap (Nolan et al. 2002).

Gray-headed Juncos breed from southern Idaho and Wyoming south to southern Nevada and eastern California east to northern New Mexico and western Texas into northern Mexico.  Gray-headed Juncos differ from Red-backed Juncos, the race found in southern Arizona and New Mexico, in having both mandibles pale, rather than the upper mandible dark.

Tuesday, September 16, 2014

Mountain Chickadee

Although Mountain Chickadees are common birds of the Rocky Mountains of North America, I have never photographed one. During our three days in Santa Fe in March, we visited the Randall Davey Audubon Center. I was delighted to find Mountain Chickadees feeding at the Center’s bird feeders.

Mountain Chickadees are Black-capped Chickadees’ closest relatives. Where their ranges overlap, they occupy different habitats—Mountain Chickadees are usually restricted on conifers, while Black-caps are limited to broadleaf vegetation. Their preferred nesting sites also tend to differ slightly, with Mountain Chickadees preferring higher parts of larger trees. However, where the species overlap and are both uncommon, like in the Rio Grande Valley of New Mexico, the two species may hybridize (Archibald et al. 1999).

Monday, September 15, 2014

Common Gray Moth

For me, eBird serves as a journal of our travels, helping me remember where and when we saw birds. I have journaled for most of my life, and, because of this habit, I was able to enter most of my bird records into eBird. But my “journaling" mostly consisted of bird lists.

When it comes to moths, I really should take notes. This Common Gray Moth was on the screen of our hotel at Big Bend National Park, and is a bit out order in my account of our 2014 travels. One of this moth's field marks is the first abdominal segment having a pale whitish band bordered by a black line, which continues onto the forewing. Common Gray Moths are found throughout North America—except in the arctic—and adults fly from March to October. The larvae feed on a variety of trees as well as on clover (bugguide.net).

Sunday, September 14, 2014

Common Green Darner

This dragonfly is a juvenal Common Green Darner. The tail is violet-brown in both the immature and in the female.  The male’s tail is blue. In both sexes, the bull’s eye pattern in front of the eyes is diagnostic.

Thousands (if not more) Common Green Darners migrate south across Minnesota and other parts of the northern United States and Canada. When they arrive in the South, they reproduce. The following generation flies back north the next spring. Then they breed, often before overwintering species emerge. After the resultant larva emerge, the young darners once again head south (Mead 2009).

Common Green Darners appear to be fairly cold tolerant. I took this individual out of my bird net on a very chilly Thursday evening—the temperature was in the lower 60s F.  I placed the dragonfly on our patio table. Instead of flying, the darner violently shivered for about 5 minutes. You may notice the wings in the lower photo are blurred. In this way, the arthropod gained body heat. When I looked out next, the dragonfly had flown.

Saturday, September 13, 2014

Yellow Female Lance-tipped Darner

On Tuesday I came upon this large, striking, yellow-striped and spotted dragonfly in a weedy patch of grass near Union Lake here in Rice Co., Minnesota—just about knocked my socks off if I had socks on, which I didn’t, since I was wearing sandals.

Female Lance-tipped Darners come in blue, green, and yellow morphs. (Here is a photo of a male.) Why do darners appear in three morphs? I previously discussed why some female dragonflies are found in two color phases. Scott King (pers. com.) muses that being yellow is advantageous as the grassy patches they inhabit turn yellow with the fall season, thus rendering the dragonfly more camouflaged. In any case, the yellow morphs tend to sport orange-brown-tinted wings, visible in these photos.

Friday, September 12, 2014

Coyote

Last March, as we left Apache del Bosque National Wildlife Refuge, we watched a Coyote saunter across a distant marsh. Across much of North America, including Minnesota, the Coyote is the most abundant large predator. In Minnesota, as elsewhere across their range, Coyotes are increasing.  In suburban areas, they prefer mixed farm and forest land, but also thrive in prairie and dense forest (MNDNR). As such, a lot has been written about this canine, both against and in support. 

Their cause is not helped by their killing large mammals and livestock as well as being a significant factor in waterfowl nest destruction. Because they are nomadic, with territories up to 36 square miles and because they usually move two or three miles a day, Coyotes probably do not cause as much duck depredation as do fox, which have much smaller home ranges. Fox can wipe out local duck populations.

On the other hand, mice make up a large part of their prey, and thus Coyotes contribute to a healthy ecosystem. We humans are not good at sharing our planet with predators. Nevertheless, Coyotes howling at a full moon is a haunting sound and an integral component of many wilderness camping trips.

Thursday, September 11, 2014

Mexican Duck

While Erika and I birded at the Bosque del Apache National Wildlife Refuge last March, I took this photo of a passing duck. I knew this might be a Mexican Duck. A Mallard should show much whiter under tail coverts. Black and Mottled ducks are not found in central New Mexico.

But what is a Mexican Duck? Drilling et al. (2002) warn, “the taxonomy of the Mallard and close relatives is complex with little agreement on how to treat some taxa.” The first problem is that Mexican Ducks and Mallards hybridize extensively in New Mexico, leading the American Ornithologists’ Union and the Handbook of Birds of the World—Alive to consider the two populations to be subspecies, with many individuals showing intermediate field marks. But this dictum does not appear to be consistent, since, despite massive hybridization, Black Ducks and Mallards are considered to be distinct species.

Just to further confuse matters, genetic studies indicate that Mexican Ducks are actually more closely related to Black Ducks than they are to Mallards. Some ornithologists think that Mexican Ducks are a recently diverged species that will become reproductively isolated from Mallards. Not helping this situation is habitat destruction and over-hunting. Mexican Duck numbers are declining in the United States. The more adaptable Mallard is holding its own, and may yet genetically swamp Mexican Ducks (Wikipedia).

Tuesday, September 9, 2014

Red Saddlebags

Last year I mentioned a New York Times article on dragonflies. The piece states that lions, scourge of the African plains, only catch about 25% of their prey. Great White Sharks, terror of the open ocean, see their attacks fail half the time. Dragonflies, on the other hand, may be “the most brutally effective hunters in the animal kingdom”—with success rates of over 95%! Not only that, dragonflies appear to be insatiable. Researchers fed 30 flies to a dragonfly in the lab and “it would have happily kept eating if there had been more food…”  Other scientists discovered that dragonfly brains are wired to focus on a single prey, keeping track of flight speed and distance. Until too late, the prey is clueless to the attack. Dragonflies come from behind and below and are able to hover, dive, fly backward and upside down. They can pivot 260 degrees in three wingbeats, which can stroke independently of each other.
I took these photos of a Red Saddlebags at Circle Lake near Northfield on 7 September. These dragonflies migrate into our area from the south, and may not be present every year. I have blogged about these saddlebags several times, including this year and in 2012. Photographing flying dragonflies takes patience and quick, manual focus. Especially the first photo falls into the Lucky Shot category.