Friday, August 30, 2013

Luecistic Tree Swallow

While birding in Rice County on Wednesday, I found swallows beginning to flock on local power-lines. One of these birds, a Tree Swallow, sported a white cap reminiscent of a South American White-capped Dipper. Clearly this individual is aberrant, a leucistic bird. Partial leucism, like on this swallow, occurs when pigment production is blocked and the result is a bird with white and normal patches. Leucistic birds generally show normally colored eyes, whereas albinos have pink eyes. Also notice the white bands on the edges of this swallow’s scapulars.

Note this bird's frayed flight feathers. Perhaps more than leucism is affecting these feathers, resulting in weak feather structure. Although I have no evidence in this case, another possibility is that other Tree Swallows have been harassing this bird. Leucistic Barn Swallows are known to be attacked by their fellow flock members (Brown and Brown 1999). Swallows can be extremely aggressive. Tree Swallows are known to kill their “step children,” when a male mates with a recently “widowed” female (Winkler et al. 2011),

Thursday, August 29, 2013

Shadow Darner

Monday, the fall banding season began not with a bird, but with a dragonfly. Odonates are difficult to remove from the bird nets. But, once untangled, having the critter in hand makes for close inspection. I should go into the field with a net. Perhaps I could drag a wagon behind me with all the equipment I would need for birding, dragonflying and banding.

The prominent throacic stripes and relatively unbanded abdomen suggested a Shadow Darner. The clincher, however, is the spine on the lower part of the long claspers at the end of the abdomen (see bottom photo). So add a hand lens to that wagon!

This is my second Shadow Darner—see post of 30 August 2011. There I wrote about this species’ adaptations to cool weather—definitely NOT a problem this year. I caught this year’s Shadow Darner, nevertheless, first thing in the morning, before the heat of the day. The darner flew across a forest opening, which happened to contain my banding net. 

Wednesday, August 28, 2013

Blackburnian Warbler

The end of August brings the first autumn migrants. The fall is my favorite season. The migrants, although definitely difficult to identify, are more plentiful than in the spring. Their numbers are augmented by the new hatch of young. Yesterday we banded a very drab, immature Blackburnian Warbler—quite a difference from a spring bird! Note the dark cheeks that are surrounded by yellow and the prominent white wing bars. Other warblers caught in the last two days include American Redstart, Wilson’s Warbler, and Northern Waterthrush.

Tuesday, August 27, 2013

Shooting Star

Dodecatheon is another genus of wildflower that depends on bee pollination. The bees hold on to the petals and gather pollen by shaking the flowers by buzzing their wings (Wikipedia). What appear to be backward-facing petals on these flowers are actually sepals.

This photo is of one of 14 species in the genus, which is found in North America and northeastern Siberia. This species is Dodecatheon puchellum, often called Pretty Shooting Star or Dark-throated Shooting Star. The species is found across most of western North America, probably south into Mexico. This photo was taken in the Black Hills of South Dakota.

Plants are found in dry soil and need at least three years to bloom. Plants can be propagated by division in winter. Some Native American tribes used Shooting Stars medicinally—as an eye wash, and a throat gargle.

Monday, August 26, 2013

Fairy Slipper

Perhaps the ice in the photo of a Fairy Slipper orchid that attracts me on this blazing hot August afternoon. As I write, temperatures are at a near record-breaking 93 degrees with high humidity. I took this photo on a chilly May day four years ago near Missoula, Montana. This orchid is also called Calypso, for its genus.

Fairy Slippers are found across the northern hemisphere, from North America, across Scandinavia, Russia, eastern Siberia and Japan. In the United States, they grow in the Rocky Mountains into the southwest. Despite this wide range, Fairy Slippers are often classified as endangered plants. They are intolerant of disturbance and are short-lived. They do not transplant well as the require specific soil fungi to flourish (Wikipedia).

The pollination of these ochids depend on specific bumblebees. The bees are fooled by the flowers, which attract the bees, but produce no nectar. The bees learn this trick and do not visit the same flowers twice, to the genetic benefit of the orchids. This deception may be the origin of this orchid’s genus, Calypso, from the Greek, meaning to hide or deceive; or the name may refer to Calypso, the daughter of gods, who kidnaped Odysseus for seven years, hoping to keep him as her immortal husband

If the present decline of bees noted across the world continues, Fairy Slippers are yet another plant in peril.

Sunday, August 25, 2013

Robber Fly 2

Camera in hand, I was sitting on the back porch, when up flew an odd-looking fly. I sent the photograph to my local entomologist, Scott King, who identified it as a robber fly, probably Machimus notatus. This identification is based on the black, rather than yellow, tibia (the first long segment) of the hind leg. I have previously posted on robber flies, though this one looks quite different from the last.

Sometimes called assassin flies, these bugs are fierce predators, taking a wide variety of arthropods, even dragonflies. They perch on low plants and attack prey in the air. These flies stab their victims with their proboscis, and inject neurotoxins and enzymes that liquify the prey’s insides. The insides are then sucked up by the robber fly.

Robber flies are not considered to be pests, unless they are feeding on bees. They can inflict a painful bite on people who handle them. Their larvae live in rotting wood and in soil.

Saturday, August 24, 2013

Albino Ring-billed Gull

Gulls are hard to identify. Many take three or four years to attain adult plumage, with different patterns in each year. Gulls often show a lot of individual variation. Complicating matters is the rare but regular occurrence of albino and leucistic birds. I believe this photo, taken many years ago in Pierre, South Dakota, is an example of a leucistic bird (an albino would probably lack the dark bill tip). A normal bird in one of its first or second winter plumages would probably be dusky and show black wing tips. A dark terminal tail band is usually present.

Friday, August 23, 2013

Great Blue Heron

Herons and cranes are usually identified by their flight silhouettes. Cranes fly with their necks extended, while herons fly with their necks folded in an S-shape. As you can see in this photo taken in Dakota County, Minnesota, this rule is not invariable. Great Blue Herons, when they are landing, chasing other herons, fleeing from predators, or courting, often fly with extended necks. This heron was landing in a nearby marsh.

Wednesday, August 21, 2013

Black Swallowtail

Black Swallowtails are common across much of eastern North America. Erika and I encountered this one in the Carleton College arboretum. These butterflies lay their eggs on plants related to carrots (Queen Anne’s Lace, carrot, celery, parsley and dill). Planting dill in your garden is a good way to attract the species. Females lay singe eggs on the leaves or flowers of the host plants. Upon hatching, their caterpillars feed on these same plants. Adult food includes Red Clover, milkweed, and thistles (butterfliesandmoths.org). Some confusion exists in the literature as to whether Black Swallowtails accumulate toxins from the plants that they eat (and are thus bad tasting or toxic to their predators) or if this species mimics similar appearing butterflies that are toxic to predators. Perhaps both statements are true, in which case Black Swallowtails are examples of Mullerian mimicry, wherein two or more toxic species look similar so as to lower predators’ learning curves.

Tuesday, August 20, 2013

Eastern Amberwing

I previously blogged about dragonfly sex. Eastern Amberwings are a bit different. The spotted-winged females, like the one above, often oviposit (lay their eggs) unguarded by their mates. In this case, however, at Carleton College’s Lyman Lakes, did her egg laying within a short distance of a territory holding male (lower photo). Males often establish territories around good egg laying sites. The enjoy a brief copulation (about 17 seconds) before leading his mate to the laying site.  Females may tap the water surface up to 100 times, facing different directions as they lay. Meanwhile the males may “take other males in tandem, perhaps to keep them from mating with [the] nearby female” (Paulson).

Monday, August 19, 2013

Lance-tipped Darner

My final photo from Carleton College’s Lyman Lakes is of a Lance-tipped Darner. This dragonfly flew up from the ground and then hung, low to the ground, among prairie grass. This behavior is typical of the species. Other darners are more likely to perch on tree trunks.

After mating, female Lance-tipped Darners lay a few eggs at a time into slits they make in tall, aquatic plant stems. The eggs may be deposited up to three feet above the water (Meade).

Sunday, August 18, 2013

Skimming Bluet

Erika and I added this Skimming Bluet to our ever-growing list of odonates. It perched in the vegetation along a dock at Roy Lake in Crow Wing County, Minnesota, on 11 August 2013. I have previously blogged that I find bluets extremely difficult to identify. With help from Scott King and also a wonderful book, Damselflies of the Northeast, I discovered the distinguishing features of this species include a wavy blue line on the side of the second abdominal segment, a thin blue eye streak, and the black last abdominal segment.

Saturday, August 17, 2013

Dragonhunter

Erika and I almost ran over this awesome Dragonhunter as we biked the Heartland Trail north of Walker, Minnesota, on 11 August 2013. The dragonfly perched at the apex of a large bridge that spans the outlet between Leech Lake’s Kabekona and Walker bays. Dragonhunters are found across much of the eastern United States and southern Canada. Minnesota lies along the western edge of their range.

Dragonhunters are huge by modern standards, being over three inches long (Paulson calls them monsters).  Different from other clubrtails, scientists classify them into their own genus, Hagenis. They are fierce predators, immune to the toxins of Monarch butterflies upon which they often feast (Mead). They attack other butterflies and even other Dragonhunters. They often attack from above, sometimes knocking their prey into the water (Meade).

Dragonhunters spend much of their time flying over water. Perhaps the bridge we were crossing attracted this female as she flew over the lake outlet. This behavior is unusual for female clubtails. Perhaps female Dragonhunters, unlike other clubtails, do not fear being harassed by males. Females usually tap the water surface with their abdomens when they are egg laying. They are also known to drop eggs into the water from the air (Paulson).

Thursday, August 15, 2013

Osprey

Erika and I are back from a couple of days in Brainard and Walker in north-central Minnesota. We enjoyed biking, birding, and dragonflying. Actually we encountered relatively little wildlife. On the other hand, mosquitos were conspicuously absent.

Loons and Ospreys highlighted our bird lists. Ospreys once built nests on treetops, cliffs, and occasionally on the ground on predator-free islands. Now almost all Ospreys use artificial sites—harbor channel markers, communication towers, utility poles, and nesting platforms built to attract Ospreys (Poole et al. 2002). The two young Ospreys in this photograph perched high atop a stadium post at the Nisswa ball park. Hats off to the city for providing these birds a sky box to root for Nisswa sports teams!

Wednesday, August 14, 2013

Spotted Sandpiper

Along with invertebrates, I also saw a few interesting birds during my recent stroll along Carleton College’s Lyman Lakes. One of these was this young Spotted Sandpiper. (For a photo of a breeding plumaged bird, see my previous post on the species.)

This young bird was with an adult, presumably a male. Males have higher levels of prolactin than females—a hormone that facilitates parental care in many vertebrates. Spotted Sandpipers have reversed sex roles—females are larger and more aggressive than males. They arrive to breeding areas first and defend territories. They then court males, lots of males. One female may have several mates, which assume care of the eggs and young. One Minnesota Spotted Sandpiper “laid five clutches for three males in 43 days” (Reed et al. 2013).

Tuesday, August 13, 2013

Goldenrod Soldier Beetle

Here is another insect from my Saturday stroll along Carleton College’s Lyman Lakes. This critter is a Goldenrod Soldier Beetle. These beetles are found in late summer, especially August. They are found in fields and gardens. They feed on flower nector—this one is on Bee Balm. They do not injure plants and do not bite or sting people. They do occasionally invade homes, where they can be swept or vacuumed. These beetles also eat other insects, like grasshopper eggs, aphids, and small caterpillars (wimastergardener.org) and, thus, are good to have in your garden.

Monday, August 12, 2013

Hummingbird Clearwing

During a short walk on Saturday along Carleton College’s Lyman Lakes, I photographed this Hummingbird Clearwing, a moth that mimics hummingbirds. Actually to me it appears to mimic three hummers—the green head reminds me of a Ruby-throated, the brown body and wings look like a Rufous, and the abdomen is reminiscent of South American coquettes.

Hummingbird Clearwings are day-flying moths and hover while the sip flower nectar. This one is at Bee Balm—they also feed at honeysuckle, snowberry, hawthorns and various fruit trees (butterfliesandmoths.org). The moth is found in gardens (where they do no damage) and city suburbs across much of North America.

Saturday, August 10, 2013

Clay-colored Sparrow

This Clay-colored Sparrow perched on a White Indigo in Carleton College’s arboretum prairie (the same field as the Field Sparrow about which I recently posted). These sparrows are abundant in shrubby prairie-lands in the northern Midwest and southern Canada. Only the conversion of these grasslands to agriculture, heavy livestock use, or urban development threaten this species.

This bird obligingly perched on a fruiting Wild White Indigo. This plant is popular in gardens and prairie restoration projects. Indigo is a native plant found in southeastern Minnesota and much of the eastern United States. The species benefits a number of insects, including butterflies. The plant, if overgrazed, is toxic to cattle. Most herbivores know to avoid indigo (Nature Conservancy).

Friday, August 9, 2013

Review: Handbook of the Birds of the World: Special Volume

The Handbook of the Birds of the World is an awesome, encyclopedic 16-volume series. Just published is a special, 17th volume, containing an index to the previous books. The usefulness of an index should be fairly obvious, especially one with references of scientific names and common names in English, French, German, and Spanish. The whole series is currently offered by the publisher for a 20% discount, or about $3700 (depending on the strength of the dollar). This price may well seem exorbitant, but works out to 30 cents a page—not bad for a book full of stunning photographs, color illustrations and text covering all the birds of the world. This price is comparable to smaller books covering only single bird families. Installment plans and free shipping are offered by the publisher, Lynx Edicions, along with samples of the format and contests of the books. Note that not all volumes are readily available through other sources like Amazon.com.

Why might someone who does not own this series be interested in this 182-page, $200 index? This book is not like any other I have ever seen.

The book contains a center section of 200 stunning photos obtained from the best bird photographers of the world. I have never seen such amazing images. For examples, a black and white wagtail feeds in a shallow puddle and looks at its mirror image; an Australian White Ibis in flight with its wings outstretched, the bird’s head silhouetted behind the feathers of the wing; a Pelagic Cormorant swimming under water among thousands of fleeing fish.

This book describes 69 new bird species discovered during the series’ publication (from 1992 to 2011). These descriptions contain text, distribution maps, photos, and gorgeous color illustrations, much in the format of previous volumes. The book branches out into the unexpected, covering 15 Amazonian birds never before scientifically named or described. Suddenly the reader enters the world of taxonomic ornithology!

Most birders are aware that avian taxonomy is in a constant state of change. DNA and molecular biology are revolutionizing how we classify birds. This supplemental volume to the handbook includes a long essay on avian classification and how it has evolved in the last 20 years. Another essay discusses where new birds are being found. Most are of limited range in areas of the world that are difficult to explore.

A forward by BirdLife International discusses the history of that august conservation organization, and may be of less interest to the casual reader than are the scientific and artistic sections of the book.

The shortcomings of the whole series are few and far between. There are few or no Illustrations of eggs. Domestic birds, for better or worse, are omitted. The series, having been published in Spain, has an Old World bias to common names (e.g., Brown Creepers are called American Treecreepers—but creepers can be successfully found in the index). Texts describing the bird families of the world tend to be poorly referenced. Overall, however, the series is mind-blowing in its coverage. If you cannot afford the price—the books have been described (by an internet reviewer) as “the world’s most expensive Christmas gift”—consider recommending it to your local or college library.

Another option exists for those of you not wedded to the printed page. The publishers have digitized the whole series, calling it “The Handbook of the Birds of the World—ALIVE” This website will be constantly updated as new ornithological discoveries are made via vetted “wikicontributions." It includes videos. By the publisher’s count, that adds up to 15 million words, 20,617 illustrations and photographs, 10,200 maps and about 100,000 bibliographical references.  The cost for on-line access is 29.95 Euros (about $40 per year), plus a 20 Euro registration fee. Ordering, which can be difficult to find on the publisher’s website, can be accomplished at http://www.hbw.com/pricing. Compared with the high price per volume of the hard copies, and the ease of Internet searching, the option of this digital subscription seems to me to be worth the expense.

Thursday, August 8, 2013

Field Sparrow

This Field Sparrow stood at attention among the profusion of yellow Compass Plants and purple Bee Balm of the Carleton College arboretum prairie. Although declining in other parts of its range, Field Sparrows are abundant in the grasslands of southern Minnesota.

I have previously blogged about Bee Balm. Compass Plants are common in southern Minnesota and elsewhere in the eastern United States. They are long-lived, up to a century (Minnesota Seasons.com). Their leaves orient away from the sun, thus often face north and south—thus the origin of the common name. Although I suspect its a good way to get lost, explorers can orient by examining the leaves. Compass Plants do not withstand heavy grazing. Native Americans used this wildflower as a tea and as a tooth paste (USDA). The species is commercially cultivated and are usally grown from seed, needing a few years to mature.

Wednesday, August 7, 2013

Andromorph White-faced Meadowhawk









White-faced Meadowhawks are abundant dragonflies around Northfield. With their white faces, they are relatively easy to identify. The first photo is of a female, the second is a male. On 1 August 2013, I took the third photo. In the field, I assumed I was seeing a male White-faced Meadowhawk. When I got home, however, I noticed that the face was actually red-tinged. Scott King, my dragonfly expert, responded that the odonate is indeed a White-faced Meadowhawk, but not a male—rather a rare andromorph female. Other dragonflies are often more prone to have andromorphs—but the trait is uncommon in White-faced Meadowhawks.

Scientists do not understand the factors that cause andromorphs. Looking like a male apparently keeps her from constant harassment from males interested in mating. Andromorphs may be more aggressive than dull females, and they often remain less hidden. Males often retreat from andromorphs, thus, compared with other females, food resources may be greater for the andromorph. She just has to convince one mate that she is, indeed, a female. The disadvantage to the andromorph, however, may be that, being brightly colored, she is easier for predators to see.

Monday, August 5, 2013

Yellow-headed Blackbird

While at the 180th Street Marsh in Dakota County, Minnesota, John Holden and I heard and then saw this juvenal Yellow-headed Blackbird. Because of its white belly, black flanks, and tan head and breast, this plumage is poorly portrayed in many field guides. Minnesota and Wisconsin are about as far east as this blackbird breeds in North America. They are become common as you travel west. Most winter in Mexico.

Breeding Yellow-headed Blackbirds are polygynous, with males holding grouped territories. Females pick nesting locations within a male’s territory. Although they usually raise but one brood, females sometimes lay eggs in more than one nest (Twedt and Crawford 1995).


Sunday, August 4, 2013

American Coot

Here is a bird that birders might have trouble identifying. Many field guides do not show this junvenal plumage of the American Coot. (Fledglings are black, with orange heads.} In the fall season, birds will molt into the black, basic plumage of adult birds. John Holden and I found this bird, one of several, at the 180th Street Marsh in Dakota County, Minnesota.

Saturday, August 3, 2013

Halloween Pennant

Erika and I have observed several Halloween Pennants this summer. This photo is from the Bass Ponds in the Minnesota Valley National Wildlife Refuge in Hennepin County, Minnesota. I have previously blogged about this hardy species, tolerant of cool and wet days. (Paulson 2011) reports that this dragonfly’s fluttery, butterfly-like flight and vague resemblance to a Monarch Butterfly’s coloration may be enough to discourage some avian predators. This hypothesis seems like kind of a stretch to me, but, if true, would be an example of Batesian Mimicry, wherein palatable species resemble distasteful ones.

Thursday, August 1, 2013

Ruby-throated Hummingbird Bathing

Weidensaul et al. (2013) tersely report that Ruby-throated Hummingbirds bathe "in water on leaf surfaces or fine spray.” This hummingbird is bathing exactly in that fashion. Yesterday, Erika and I visited the Funky Garden nursery in Washington Co., Minnesota, just north of the William O’Brian State Park. An employee of the nursery moved a water sprinkler that began to soak a small tree among the flower beds. Twice this Ruby-throated Hummingbird flew up to the tree and perched at the top. It fluttered its wings and ruffled its feathers as it perched.
After its second bath, the bird remained perched for a few seconds as the water receded. Perhaps the bird enjoyed a  bit of warm sunlight before it flew off. If you look closely at the last photo, you may notice that this hummingbird appears to be banded on its left leg. Even greatly enlarged copies of the photo do not positively prove that the bird is banded—try magnifying the photo on your computer (“command +” on a Mac). Does anyone know of someone banding hummingbirds in Washington Co.? Hummingbirds are not banded by the majority of banders since doing so requires special permits and bands.)
Finally, on the right side of the first photo, there is a UFO—an Unidentified Flying Object.  A falling acorn? I might add that, in the first and last photos, the hummingbird appears to be uncharacteristically yellow-breasted. This color is a reflection from the tree leaves.