Wednesday, August 31, 2016

Short-billed Dowitcher


Short-billed and Long-billed Dowitchers can be identified by call. The flight call of the Short-billed is a “tu” note repeated up to three or four times. Long-billed Dowitchers gives a high “keek” note, given once or repeated several times (Jehl et al. 2001). When I began birding, the dowitchers were considered to be one species. Peterson, in his early field guide, wrote, “the Dowitcher feeds like a sewing-machine, rapidly jabbing its long bill perpendicularly into the mud.” You can see this feeding strategy in the second photo.

Silent dowitchers, like this one Erika and I photographed last Saturday at the Jirik Sod Farm in Dakota County, are another matter. Some dowitchers, depending on the season and the birds’ race, are probably not separable in the field. Long-bills can have shorter bills than some Short-billed Dowitchers. Most plumage characteristics are shared by at least some birds of both species. 

I think, nevertheless, that our bird is clearly a Short-billed Dowitcher. Compare it to a Long-billed Dowitcher that I photographed some time ago in South Dakota (see last photo). The Minnesota bird clearly has a much shorter bill than the Long-billed. The Minnesota dowitcher also appears to be a much smaller bird, although females of both species are smaller than their males. As a result, the relative size of the bird can only be used in extreme individuals. Note the speckles along the Minnesota bird’s flanks. The Long-billed has barred flanks. The Short-billed Dowitcher is a much paler species. Finally, if you use a bit of imagination, you can see that with wing tips of the Minnesota bird extend a few millimeters beyond the tail tip. Long-billed Dowitcher wing tips usually do not extend beyond the tail.

Tuesday, August 30, 2016

Baird’s Sandpiper

This wet August has resulted in many flooded fields, especially in area sod farms. Birders often visit the Jirik farm in Dakota County during shorebird migration. Erika and I have made several trips there this season. We have not had much luck, although you may recall a recent photo of a Stilt Sandpiper. On 27 August 2016, we found a Baird’s Sandpiper in one of the pools at the farm.

This shorebird is one of the last North American sandpipers to be described. It breeds in northern-most Canada, Alaska, and parts of Russia. In 1861, Elliot Coues named it for Spencer Fullerton Baird, the secretary of the Smithsonian Institution. It makes a rapid migration, in as few as five weeks, to South America—some all the way to Tierra del Fuego (Moskoff and Montgomerie 2002).
This Baird’s Sandpiper behaved oddly, stretching out its neck and yawning. I have seen a Spotted Sandpiper behave similarly. Female Spotted Sandpipers gape when courting males. The Baird’s fed close to a Short-billed Dowitcher and a few Killdeer. Possibly the Baird’s was defending a feeding territory—other shorebirds defend feed territories during migration—or perhaps it was regurgitating arthropod shells. The Baird’s also stretched its wings, which is also similar to breeding territory displays. In this case, wing stretching may have served as an intra-species feeding territory defense. At the time, however, I assumed the sandpiper was only stretching.

Monday, August 29, 2016

Eastern Tailed-Blue

On 21 August 2016, Erika and I found a dozen Eastern Tailed-Blues. Many butterflies feed on pollen, but others prefer urine and, in this case, excrement. Larvae eat various legumes, which are common along our trail in the Carleton arboretum. The larvae secrete substances that attract ants, which, in turn, protect the larvae from various predators.

Tailed-blues are hard to photograph, since, when they perch, they keep their wings folded. They look gray, until, suddenly they flutter away in a blaze of azure. On this day, they looked like sailboats keeling against the wind. Occasionally a gust knocked a few completely over.

These butterflies’ tails are just visible in this photograph. Note the tails along the wing edges, opposite the orange spots, on the furthest left butterfly. Often the tails wear off as the season progresses. 

Sunday, August 28, 2016

Wasps


Last week in Carleton College’s arboretum I took two wasp photos. I used Scott King’s new Minnesota wasp book to identify them. I based my identification of the first wasp on its black-tipped abdomen and orange legs—a Great Golden Digger Wasp. These wasps are not aggressive towards people. They dig tunnels to which they bring paralyzed prey. The females lay eggs in the prey and then cover the tunnels. The wasps do not actively defend their nests (www. insectidentification. org).

I had more trouble identifying the second, other-worldly looking wasp. Note the long ovipositor. I got additional help from Scott, who confirmed this species is an American Pelecinid Wasp. This pollen-consuming wasp is found from Canada to Argentina. They lay their eggs in June Beetle larvae The beetles are not necessarily eaten alive, as the wasp is not adverse to consuming dead tissue (University of Wisconsin).

Saturday, August 27, 2016

Black-throated Green Warbler

I banded this Black-throated Green Warbler on 25 August 2016. In the spring, this warbler’s black throat contrasts sharply with its golden face. Even in the fall, this bird is striking. The eastern ranging Black-throated Green Warbler is similarly plumaged to a number of western species (Golden-cheeked, Hermit, Townsend’s warblers). These species seem to be closely related. Their ancestors may have been a single population that became fragmented and isolated by Pleistocene glaciations (Morse and Poole 2005). In any event, Black-throated Green Warblers, which breed in northern and Appalachian forests, are one of our most common warblers.

Friday, August 26, 2016

August Warblers

Fall Warblers are notoriously difficult, but not impossible, to identify. They are often referred to as CFW’s, Confusing Fall Warblers. Here I post six I banded in Northfield on 22-23 August 2016. I have linked each to previous blog posts showing spring birds and to some ecological notes. Here I discuss only their field marks. The first photo is of a Golden-winged Warbler. Because in the fall this species looks similar to spring birds, this CFW is one of the easier ones to identify. This warbler is a female, and is easily recognized by its dark cheeks, yellow crown, and golden wing bars.

This second warbler is also not difficult. Canada Warblers are proclaimed by their golden lores, white eye rings, and black necklaces. Males have darker necklaces than females, but many fall birds are intermediate, making sexual identification difficult.
This third bird is a hard one. The gray head, white eye ring, and pale throat proclaim it to be a Nashville Warbler. Even in the fall, many Nashville Warblers have much brighter yellow throats than this drab-plumaged immature. In the two days that I took these photos, I banded 32 birds—20 were Tennessee Warblers.
Chestnut-sided Warblers are a bit easier. Their gray underparts contrast with their white eye-rings. Their crowns are bright yellow, such as occasionally found in tropical tanagers.

Tennessee Warblers show considerable variation.  Often they are muted shades of yellow. This gray-headed individual is one of the few adult warblers I banded this August. In any plumage, a good key to identification is the black line through the eye. The predominance of young birds has me a bit puzzled.

This final bird is the toughest of the lot to identify. Note the bright yellow underparts and weak white line surrounding the eye. The bill is relatively robust, at least compared to the other warblers on this page. One key to the identity of this Mourning Warbler is the dark line below the throat. 

Thursday, August 25, 2016

Black Turnstone

eBird posts monthly challenges to contributors. Those meeting the goals—numbers of lists per month, lists with breeding notes, lists with birds noted flying overhead—are then placed in a pool from which a single prize of binoculars and bird books are drawn. Your chance of winning are poorer than collecting something from Power Ball. (You have a 1 in 27 chance of winning $4 if you hit the Power Ball.)
I am enjoying this month's challenge to submit bird lists containing at least three photographs. This quest proves entertaining and surprisingly difficult. I did not realize how many birds I identify from a great distance or by call. Along the way, I notice that the links to many of my previous photographic submissions to eBird are corrupted. Before, the images were linked to Flickr or Google Album pages. Now you submit the photos through eBird directly to the Macaulay Library at Cornell University. I have spent the month correcting my list links and moving photos to Macaulay. 

I found a few birds for which I have photographs but have not appeared in this blog. One is this Black Turnstone I from La Jolla, California, on 8 January 2008. This species breeds on the Bering Strait coasts of Alaska and winters along the Pacific Coast from Alaska to Baja California and northwestern Mexico. It occurs on rocky shores, where it flips stones in search of algae, invertebrates, and “all sorts of supratidal jetsam” (Handel and Gill 2001).

Tuesday, August 23, 2016

Northern Map Turtle

On 11 June 2016, Erika and I were biking the Cannon Valley Trail. Near a bench, we found this Northern Map Turtle laying her eggs in the sand by the trail. This encounter was strange, since map turtles usually prefer large rivers and lakes. This turtle had a long haul, perhaps a quarter mile up hill, from the Cannon River. You would expect her to nest on sandy beaches or sandbars, not in a wooded area.

Breeding occurs in the spring and fall. Most mating occurs in deep water. Judging by the algae on this turtle’s carapace, this individual does spend most of her time in the river. Hatching happens in the late summer. A dozen eggs are laid a few times a year. Warm temperatures produce females, cooler weather results in males. When young hatch late in the year, they may overwinter in the nest (Savannah River Ecology Lab, Wikipedia)

Sunday, August 21, 2016

Bobolink

Last Tuesday I checked out the Dennison Sewage Treatment Plant on the eastern edge of Rice County, Minnesota. Sewage treatment plants and garbage dumps often harbor interesting birds. I  found none of my hoped for shorebirds—but I did find some good birds. Among them were a flock of eight Bobolinks. Winter Bobolinks are drab, compared to the males’ black and white spring plumage.

Curiously, I saw Bobolinks at the Dennison treatment plant almost exactly a year ago. Then I commented that the males in winter plumage tend to be brighter breasted than the duller females. I assume the bird in this photo is a male. In another bobolink post, I wrote “Bobolinks are long-distance migrants, wintering in southern South America, a round-trip distance of about 12,500 miles. A banded female Bobolink was recaptured after nine years, thus “presumably made this trip annually, a total distance equal to traveling 4.5 times around the earth at the equator” (Martin and Gavin 1995). Studies indicate that Bobolinks orient using magnetic clues.”

Saturday, August 20, 2016

Skimming Bluet

Skimming Bluets often fly low and hover over open water—hence their name. They are partial to algae mats and vegetation in otherwise clear-water lakes and ponds. They fly in the middle of day when temperatures are high. These are exactly the behaviors and habitat that Erika and I found them in along the outflow to Hiawatha Lake in Minneapolis on 26 July. All bluets look more or less the same—Erika says, “you’ve seen one bluet, you’ve seen them all.” The Skimming Bluets are small with mostly black, black-tipped abdomens. If you look closely at the eyes of the perched bluet, you may notice that they have a blue streak, but are otherwise brown. This field mark is diagnostic. You should also note the wavy blue line on the side of the first abdominal segment.

Friday, August 19, 2016

Field Sparrow

On 30 May 2016, Erika and I walked up to this Field Sparrow. It must have been near a nest. It bird first watched with its back to us. Then it hopped around and faced us. What a strikingly beautiful sparrow!

Field Sparrows are common across much of eastern North America. These sparrows prefer over-grown pastures and scrub. They do not nest in suburbs. Their clear trill as been compared to a bouncing ball. Take a listen and see what you think:

Wednesday, August 17, 2016

Spotted Spreadwing


This Spotted Spreadwing searched for me. On 9 July 2016, Erika spied this tiny damselfly on the  inside, garage wall.  Two dark spots, barely visible on the underside of the thorax, cinch identification. This species is found across northern North America. Their range dips further south down the West Coast and in the Appalachians. 

Tuesday, August 16, 2016

Black Swallowtail

Black Swallowtails are common garden butterflies across eastern North America. They also occur from Mexico into South America. I photographed this swallowtail on 8 August 2016 at the Open Hands Farm, near Northfield in Dakota County.

Black Swallowtails prove to be interesting butterflies. Males form leks. They gather at display sites where females mate with them (Wikipedia). Females are less brightly colored than males, and may mimic the distasteful Pipevine Swallowtail. The males’ bright dorsal spots do not mimic other species. These spots serve as territorial markers (University of Florida).

Caterpillars mimic bird guano. The caterpillars are often considered to be pests. They eat plants in the carrot family, including caraway, celery, dill, parsley and sweet fennel. They are not a serious problem for commercial agriculture. In home gardens, hand killing the caterpillars should keep them under control. Insecticides can provide control, but the caterpillars have a lot of insect predators and wasp parasitoids that provide natural control (University of Florida).

Sunday, August 14, 2016

Ira Allen

The last stop on our spring trip was at my brother’s near Williamstown, Vermont. We had a hard time getting there. The rain of Martha’s Vineyard changed to snow. We arrived a day late and left a day early. We had planned to return to Minnesota through Canada. North Bay was expecting over a foot of snow. Suddenly driving home through Chicago seemed a better alternative.

My brother and his wife proved to be understanding and exuberant hosts. They shared their home and harvested maple syrup. We took long and interesting hikes. This stone—notice the snow—is a boundary marker placed by Ira Allen in the 1700s. The rebar next to the stone is a modern survery marker—Ira was right on. Ira was the youngest sibling of revolutionary war hero Ethan Allen. Ira founded the Univesity of Vermont in 1791 and was a representative in the Republic of Vermont. My sister-in-law writes, “these Vermont heroes were admittedly scoundrels as well....or very good at self-preservation and self-promotion. Ah, history as mythology…”

Saturday, August 13, 2016

Stilt Sandpiper

Yesterday, Erika and I photographed this young Stilt Sandpiper at the Jirik Sod Farm in Dakota County. (We’ve had a bit of rain the last two days.) I have previously posted photos of adult Stilt Sandpipers from South Dakota.

In that former post, I wrote that Stilt Sandpipers are thought to be relatively rare shorebirds, but their numbers may be under-estimated by biologists. Habitat destruction, both in their arctic breeding grounds and in their south American wintering areas, have probably caused population declines.

Young Stilt Sandpipers can be tricky to identify. Field marks to note include the relatively long and somewhat drooped bill, the yellowish legs, and the scaly back. Winter-plumaged adults are much grayer birds. Stilt Sandpipers also tend to feed in almost belly-deep water.

Friday, August 12, 2016

Review: Wasps and Bees of Minnesota


Friend, poet, and citizen scientist, Scott King has written “A Photographic Guide to Some Common Wasps and Bees of Minnesota.” This book is not so much a guide as it is an appreciation of Minnesota wasps and bees. This book is extremely relevant in these days of concern for declining bee pollinator species.

This book contains color photographs, mostly taken by Scott, of 135 of the 400 species known to occur in Minnesota. Scott’s goals in writing this book are to increase readers' awareness of bee diversity and perhaps to learn to identify the common species. But his greater goal is to share his excitement in studying these insects. Scott is thrilled to search for new species, acquire names, and learn apian biology. By his own admission, this book is not technical. Identification is to be attempted by thumbing through the book. Sizes are indicated by lines of different lengths, but the measurements are not given. No keys are included. Scott writes that one in ten wasps you might find are not in this book. He notes that finding new species for Minnesota is not difficult. New species to science are not out of the question.

Despite these caveats, this book will allow you to name many Minnesota bees and wasps. Scott quotes Dijksra who wrote that names lead people to “awareness, conservation, and research.” Some great wasp and bee names are lurking out there—Queen Ant Kidnappers, Ornate Variable Spider Wasps, and Eastern Cicada Killers, to name but three. Some had no common names, and Scott had to pen them based on their scientific names or habits. All await your discovery. Click on the icon above for more information.

Thursday, August 11, 2016

Wandering Glider

I have seen Wandering Gliders a few times during my dragonfly career (which began in 2010). Previously these dragonflies flew high over the Carleton College arboretum prairie. In that second link, I wrote about this glider’s amazing distribution—it is found on every continent except Antarctica.

On 2 August 2016, Erika and I encountered a large dragonfly hovering above our prairie path. It hovered almost motionlessly about 15 feet in the air.  A few more Wandering Gliders flew between grassy perches along the trail’s edge. Mead reports that this glider often hovers. Paulson writes that this species is basically tropical, with northern records of possibly non-breeding individuals, occurring after warm fronts—precisely the weather conditions in which we found ourselves.

Tuesday, August 9, 2016

Meadowhawks

These dragonflies are meadowhawks. The first two, from 21 June 2016, were taken at the Lebanon Hills Regional Park in Dakota County. The red one is an adult male White-faced Meadowhawk. Note its white face and black legs. The second is an immature Autumn Meadowhawk. Look at its yellow legs. This dragonfly was once called the Yellow-legged Meadowhawk. The last meadowhawk is also an Autumn Meadowhawk. I took this closeup in Erika’s garden on 29 July 2016.
Poet and citizen scientist Scott King, my dragonfly guru, writes, “I like the meadowhawks. Though the Autumn Meadowhawk always signifies that summer has peaked, at least to me, so I'm a little wistful at its first appearance but then grow more and more fond of it as the season advances and it's the last thing flying.”

Monday, August 8, 2016

Martha’s Vineyard

The goal of our spring trip was Martha’s Vineyard. We attended the memorial service for my aunt, a beautiful and moving experience. The weather was awful. For four days, it rained—too cold and wet for dragonflies. In this photo of the Gay Head cliffs, it was pouring rain. We saw interesting birds—eiders, scoters, and even a Black-headed Gull, but they were distant and one hardly dared to expose a camera to the elements.

Sunday, August 7, 2016

Northern Mockingbird

One of the delights of birding is that birds may be rare at home, but common in your journeys. Such is the case with Northern Mockingbirds. At the end of March, mockingbirds were singing in New York. Male and females sing. Males may sing 150 song types, and increase with age. They mimic each other, different species, and mechanical sounds  (Farnsworth et al. 2011). As a youth in Washington DC, I heard mockingbirds mimic passing trains.

Saturday, August 6, 2016

Skunk Cabbage

Spring was barely awake at the end of March in New York. Skunk Cabbage is an early sign. This plant is found in northeastern North America. Tearing a leaf produces a skunk-like odor. The smell attracts pollinators and may dissuade potential herbivores.

Skunk Cabbage is one of the few plants demonstrated to produce heat. The plant can generate up to 63 degrees F., thus able to melt its way through frozen ground.  This ability allows it to germinate in early spring. The heat may also spread its odor, attractive to its pollinators.

Skunk cabbage was used by native Americans and colonists for treating respiratory diseases, nervous disorders, rheumatism, and dropsy. The roots and leaves are toxic, but the leaves were dried and used in soups (Wikipedia).

Thursday, August 4, 2016

American Robin

We visited Fishkill, New York, and Erika’s sister for two days, beginning 30 March. My in-laws were not pleased with this American Robin. The bird constantly attacked its reflection in their car window, hood, and mirror—often violently. But the territory invader never flew away. Birds do not have over-whelming powers of reasoning. Usually they can fly away from their problems.
Our hosts’ car was a mess. If you look carefully, you might find a rare (perhaps only) selfie I have ever taken. Perhaps taping raptor silhouettes to the car windows would frighten this amorous robin. This solution, however, would make driving the car through New York traffic a bit more difficult.

Wednesday, August 3, 2016

Eastern Amberwing

Here are a female and male Eastern Amberwing. The first is a female from the River Bend Nature Center here in Rice County. The second is a male form where Lake Hiawatha flows into Minnehaha Creek in Hennepin County.

Entomologists believe these small dragonflies are bee mimics. A quick look at them may dissuade predators from attacking. Denis Paulson wrote that this species is “sufficiently wasplike to fool an odonate enthusiast and presumably an insect-eating bird.” Amberwings are extremely terrtiorial. They team up to attack other males,  thereby protecting nearby females. They even attack other insects of similar size and color, perhaps even they can’t tell each other from wasps (Paulson).

Tuesday, August 2, 2016

Northern Gannet

We found Northern Gannets at several locations as we drove up the East Coast in late March. This one flew off of Ocean City, Maryland. Gannets are restricted to only six colonies in North America—three in the Gulf of St. Lawrence, and three off the Newfoundland coast. Gannets also breed in northern Europe. Our birds winter from Maine to south Texas.

Gannet reproductive success is high, fortunately, since they raise only one chick each year. Most colonies are increasing at a rate of 3 to 5% per year (Mowbray 2002).

Monday, August 1, 2016

Dot-tailed Whiteface


We’ve seen a lot of Dot-tailed Whiteface this summer. One of the first was this male, on 6 June 2016, in the Carleton arboretum.
On the same day, 6 June 2016, I found this whiteface at our water feature. I knew it was a Dot-tail, but I was surprised when Scott King told me that it is an andromorph female. Scott says andromorphs, when females look like males, are relatively uncommon in this species. The hypothesis is that females that look like males still get the job done, but with a whole lot less hassle from the males.
This final photo is of an immature male—note the yellow bands on the top of his abdomen. We found him on our 21 June 2016 hike at the Lebanon Hills Regional Park. You can clearly see his white “face.” On this day we kicked up swarms of dragonflies. This one is on Erika’s shoe. I will always remember Erika’s walking up the path, with dragonflies scattering in all directions.