Friday, August 31, 2018

Ruby-throated vs Black-chinned Hummingbirds

Every fall I watch for vagrant hummingbirds at our feeder. On 27 August 2018, this there appeared this noticeably white-breasted hummer. A grayish crown, grayish ear patches, and a long, slightly down-turned bill are all field marks of a Black-chinned Hummingbird. I rejected this identification because Ruby-throated Hummingbirds are by far the most abundant hummingbirds and because this bird’’s wing feathers are the wrong shape for a Black-chinned.
Black-chinned Hummingbird wings, like on this bird we saw on 12 August 2018 in Denton County, Texas, have curved, sickle-shapped outer primaries. Ruby-throated Hummingbirds have more or less straight primary feathers. So its back to the rare hummingbird lookout. One of these days… Our Texas bird, by the way, was hawking for flying insects, one of which is remarkably in focus in the last photo.

Thursday, August 30, 2018

Little Blue Heron

During our recent Texas trip, we listed several immature Little Blue Herons. The first photo, taken on 10 August 2018, investigated the banks of the Elm Fork of the Trinity River in Denton County below the Lewisville Dam. The second hunted for minnows at the Fort Worth Nature Center and Refuge in Tarrant County, Texas, on 11 August 2018. As they age, these white birds become dark blue. Rogers and Smith (2014) assure us that Little Blue Herons are opportunistic feeders, consuming small fish, amphibians, and aquatic and terrestrial invertebrates.

Wednesday, August 29, 2018

Red Saddlebags


Red Saddlebags are common in Texas. We took the top photo at the Knob Hill Bike Trail in Denton County on 12 August 2018. The species is also fairly common in Minnesota, at least in the southern part of the state. We took the lower photo on 22 August 2018 in the Carleton College arboretum. 

Monday, August 27, 2018

Spot-winged Glider

I was surprised at the number of Spot-winged Gliders we saw during our August Texas trip. This photo was taken on 12 August 2018 at the Knob Hill Bike Trail in Denton County. Spot-wingd Gliders are found across much of the United States—except for the Northern Plains and Rockies. They are also observed south to Argentina and have scattered records north to Alaska. I have a previous record from Minnesota. Spectacular migratory flights are often reported (Paulson 2011).

Sunday, August 26, 2018

Roseate Skimmer

Our last Texas hike during our recent visit was to the Knob Hills Bike Trail north of Roanoke, in Denton County (12 August 2018). We saw several species we’ve listed on previous expeditions and on this trip. A red dragonfly with purple sides is probably a Roseate Skimmer. We also saw one in Costa Rica. Roseate Skimmers are widespread—they are found across much of the southern United States south to Costa Rica and Cuba —and readily spread into new locations. They are tolerant of a wide variety of habitat and water conditions.

Saturday, August 25, 2018

Checkered Setwing

On our last afternoon in Texas, 12 August 2018, we briefly explored the Knob Hill Bike Path in Denton County. In a opening in the dry brush, we found a lovely, small, yellow-spotted dragonfly making sorties from piles of brush, a behavior typical for the species. The black patches in this Checkered Setwing are the key to its identification. Checkered Setwings are found in Texas,  the Southwest and adjacent Mexico.

Friday, August 24, 2018

Cyrano Darner

One of the great advantages of searching for dragonflies with your son is his vision. David, driving, spotted this darner as it flew across the road and perched in nearby shrubbery. We were in the Fort Worth Nature Center and Refuge in Tarrant County, Texas, on 11 August 2018. This Cyrano Darner, a first for me, is also found in Minnesota, and most of the eastern United States and Canada. 

Cyrano Darners presumably get their name from their projecting forehead. They stick to wooded areas, and fly along woodland edges, paths, and, in this case, roadsides. This species is known to take larger prey than other darners.  If you look closely, note that this Cyrano Darner is consuming an Eastern Pondhawk!

Thursday, August 23, 2018

Monarch Butterflies

Yesterday, 22 August 2018, Erika and I discovered thousands of Monarch Butterflies in the Carleton College arboretum in Dakota County, Minnesota. Although it was almost noon, the butterflies appeared to be roosting at the edge of an oak forest on the west edge of the prairie. Some of them were mating. As we walked down the path, hundreds flushed in front of us. We have never seen such a concentration of butterflies. The scene reminded us of photos of monarchs wintering in Mexico. Getting a photo of the swarm proved impossible, and I never thought of trying to take a video. This concentration of butterflies does not appear to be a local aggregation, since K. C. Jensen recently reported large numbers of Monarchs in Brookings, South Dakota.

Wednesday, August 22, 2018

Scissor-tailed Flycatcher

We added few new birds to our year list during or quick trip to Texas this August. We did capture a few images of young Scissor-tailed Flycatchers at LLELA (Denton Co.) on 10 August. The adults have such long, graceful tails compared to the immatures. I often wonder why these flycatchers, whih specialize in eating grasshoppers and beetles, are common only in thee southern Great Plains. Perhaps they require more trees and shrubs than are afforded by the northern prairies.

Tuesday, August 21, 2018

Springwater Dancer

Due to the dark spot near the end of the abdomen, we identified this damselfly as a Springwater Dancer. We found it at the Lewisville Lake Environmental Learning Area (LLELA) in Denton County, Texas on 10 August 2018. We found it at a wet meadow, which should be perfect habitat for this species. They are often found along roadsides. Assuming we are correct in our identification, this record is a first on Odonata Central for Denton County.

Monday, August 20, 2018

Kiowa Dancer

We saw two dancers at Lewisville Lake Environmental Learning Area (LLELA) in Denton County, Texas on 10 August 2018. Many damselflies are notoriously difficult to identify. The first is this Kiowa Dancer, told by the spotted appearance of the sides of its abdomen. Tnis species is common in most of Texas, especially along roadsides and trails. Like this one, they often perch on or near the ground.

Sunday, August 19, 2018

Swift River Cruiser

I don’t believe we would have seen this Swift River Cruiser were it not for David’s relatively youthful eyes. He, Erika, and I searched the Lewisville Lake Environmental Learning Area (LLELA) in Denton County, Texas on 10 August 2018. This beautiful dragonfly flew up and perched, hanging high in a tree. I knew river cruisers existed, and always hoped someday I would see one. Not only was this species new for me, it was also the first I have seen of the family Macromiidae. They range across much of eastern North America, with sporadic western records. The slightly spatulate-shaped abdomen is one key to identifying Swift River Cruisers. 

I am not sure if this dragonfly flies swiftly, or if it prefers to fly fast rivers. They are often encountered near rivers, but often fly over forest clearings. Especially during hot weather, they hang at moderate to high levels in forest vegetation (Paulson 2011). They are common in eastern Texas and, although we saw this one at midday, they are usually most active in the mornings (Abbott 2015).

Saturday, August 18, 2018

Slaty Skimmer

10 August 2018 found Erika and me meeting our son, David, in Denton County, Texas, at the Lewisville Lake Environmental Learning Area (LLELA). I have no idea why it took David 40 years or so to become passionately interested in birds and dragonflies, but, hey, better late than never! We had a blast searching this wildlife preserve alongside the Lewisville Lake Dam.

David pointed out Slaty Skimmers which were new to us, although abundant in many parts of the Southeast, Well, not quite new, since Erika and I found the female Slaty Skimmer in eastern-most Oklahoma the day before. At LLELA, Salty Skimmers were everywhere. Most were males and all perched low in the trailside vegetation. Their dark faces and brown eyes separate them from similar species.

Friday, August 17, 2018

House Wren

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This House Wren obligingly posed for me, while I walked in Northfield on 6 August. House Wrens range across much of North and South America. They are common near people. Populations often increase when forests are cut for housing developments. In fact, populations in Rhode Island actually decreased when human development was in the form of clustered subdivisions that left intact small areas of forested land (Johnson 2014).

Thursday, August 16, 2018

Common Yellowthroat

A female Common Yellowthroat along a Northfield lakeshore on 6 August. This species can be difficult to identify, but can be told by their yellow throats an brown crowns. Yellowthroats are widespread and common across most North America, breeding from Alaska through central Mexico. The Common Yellowthroat is one of the first North American birds described by European ornithologists. Linnaeus named it in 1766.

Monday, August 13, 2018

Solitary Sandpiper

Continuing my eBird 50 bird photographs in August challenge, I happened upon a Solitary Sandpiper. Seeing this shorebird was a delight, since  I inexplicably missed seeing one this spring. It probed the shallow water, as sandpipers often do. Looking at my photos, however, I was surprised that the bird apparently shut its eyes as it made its probes. Many shorebirds have tactile sensors at their bill tips. It would appear that they do not have to depend on eyesight. The first image suggests that the sandpiper does initially locate prey by sight, since the head is slightly turned to the side.

Saturday, August 11, 2018

Hooded Merganser

On 6 August I found an immature Hooded Merganser in a Northfield pond. In its mouth, the duck carried a crayfish. Suddenly the crayfish was in the air. I thought of calling this post "Who Knew Crayfish Flew?
I am not sure how this crayfish became airborne. The merganser may have simply dropped the crustacean. Possibly the bird may have shaken the crayfish in an attempt to kill it, and accidentally lost grip. Or perhaps the bird intentionally threw the crayfish into the water to drown or clean it. The crayfish submerged and the merganser dunked its head under the water to retrieve its prey.
The Hooded Merganser carried the crayfish for several minutes, until the crustacean was finally swallowed. These mergansers are known to be particularly fond of crayfish, and are also known to take fish and insects. Dugger et al. 2009 write that Hooded Mergansers, compared to other ducks, have thicker gizzards to grind and digest crustaceans. Further, the serrated bill edges are used to grasp and handle mobile prey.

Thursday, August 9, 2018

Double-crested Cormorant

I keep my birding records on eBird. This digital app keeps track of when and where I see birds. Every month. eBird puts forth a challenge, the winner to receive a pair of binoculars. Your chances of winning an eBird challenge are worse than picking a minimal Powerball number. That doesn’t matter too much, since I have no interest in the eBird prize. Photos are deposited in Cornell University’s Macaulay Library—they currently have 7.5 million photos submitted through eBird. Curiously, their most photographed bird is Red-tailed Hawk, with over 63,000 submissions.

This month’s challenge is to submit 50 bird photographs (or other media formats). Photographs are easily submittable, and can verify many of your less common bird sightings. The challenge has me running around the county taking pictures of common birds. There is nothing noteworthy about a Double-crested Cormorant in Rice County, Minnesota. But the cormorant bathing is of passing interest, and well described in the literature. When bathing, “the body rolls back and forth in a rocking-horse motion, while the wings splash loudly on the water, throwing a spray onto the back of the bird” (Dorr et al. 2014).

Tuesday, August 7, 2018

Veiled Lady


This image of a Veiled Lady fungus is perhaps my last photo from Costa Rica. We found it along the roadside at the Laguna del Lagarto Lodge in northern Costa Rica. Although we lack the expertise to determine the species, this fungus is classified with the stinkhorn mushrooms in the genus Phallus, obviously an appropriate name (unless you are describing a lady). Most of this genus have a white veil, which may serve as a ladder for insects attracted to the fetid odor that the stinkhorn emits. The insects spread spores that pass through their digestive systems. We do not know if this mushroon’s yellow veil is typical for this species.

Sunday, August 5, 2018

White-nosed Coati

I found a couple of additional photos we took during last year’s Costa Rican trip. These are images of White-nosed Coatis. These mammals are found from New Mexico and southeastern Arizona through Panama and, perhaps, into Colombia. Feral coatis also roam about Florida, where they have escaped from captivity since 1928.

Coatis are in the same family as Raccoons, but are more arboreal. They are similar, however, in their omnivorous diet. They consume small vertebrates, fruits, carrion, insects, snakes and eggs (Wikipedia). Like Raccoons, they habituate to humans and raid campsites, trash, and even, such as these coatis at the Laguna del Lagarto Lodge in northern Costa Rica, visit bird feeders. Adult males tend to be solitary, but other ocatis travel in social groups.

Saturday, August 4, 2018

Ruby-throated Hummingbird

This female Ruby-throated Hummingbird perched on our hummingbird feeder during a rainstorm on 1 August 2018. She held her bill skyward and appeared to have her eye closed. Perhaps she was resting in these cool, wet conditions. Hummingbirds are able to generate heat via their hovering. Females are more efficient heat generators than males. During really cold weather, Ruby-throated Hummingbirds become torpid (Weidensaul et al. 2013). I doubt, however, that conditions were sufficiently stressful for torpor on this day.

Wednesday, August 1, 2018

Giant Swallowtail

A Giant Swallowtail in Erika’s Northfield garden. They have probably visited before, but they don’t appear every year. They disperse to the North Country sporadically in different years. This unusually hot summer would seem to be a candidate for their appearance. The fly all year in the southernmost United States, but only during the summer further north. Rescently they have become common in the Los Angeles Basin, and are their caterpillars are accused of destroying ornamental citrous leaves (Brock and Kaufman 2003).