Wednesday, July 31, 2013

Eastern Tiger Swallowtail

On Sunday, Erika and I were pleased to see this Eastern Tiger Swallowtail in northwestern Minneapolis. This butterfly is common across most of the eastern United States. The Washington Post, however, warns that many butterfly populations are falling in our country. Causes for this decline include habitat destruction and widespread use of pesticides and herbicides. Some of my fellow bloggers have noticed a decline in butterfly populations here in Minnesota, although these local observations are antidotal, not backed up by scientific sampling.

Tuesday, July 30, 2013

Junvenal Birds

Imagine that you were a birder from a different continent. Identifying the two birds pictured on this post might give you trouble. We Minnesotans recognize the first bird as a Northern Cardinal. But a visitor would have trouble finding it in a Sibley field guide. The bill is not orange. The bright red breast feathers suggest a Pyrrhuloxia from the southwestern United States and Mexico. Sibley shows no cardinal-like bird with an odd, white beard under the bill. This Northern Cardinal is molting from its juvenal feathers into a male, First Basic Plumage. As with many youngsters, he is not going by the book.

The second bird might give our visiting birder even more trouble. The yellowish wash on the breast suggests a Lincoln’s Sparrow. The yellowish lores suggest a Savannah Sparrow. Sibley does illustrate this bird, although he shows an even brighter juvenal Song Sparrow. Sibley indicates these colors are typical of eastern Song Sparrow, but even birds from Minnesota can be even brighter yellow. Sibley instructs us to note the buffy eye-ring. Readers of this blog may recall a post showing a brighter yellowish Song Sparrow that I banded several years ago.

We are finally, at the end of July, capturing our first rush of recently fledged birds at our banding station. As you can see, identifying these birds is keeping us on our toes.

Sunday, July 28, 2013

Common Buckeye

Birders have eBird. Dragonfliers have Odonata Central. Now butterfly enthusiasts have eButterfly. The eButterfly site, originally built to document the identity and distribution of Canadian butterflies, now covers the United States. Those interested can submit photos which are then vetted by experts. Accepted records are then plotted on a map, which can be accessed by those wishing to learn the distributions of individual species. If you try this out, be sure to click “English” rather than “Latin” if you enter a common name.

This site is still in its infancy (at least for the United States). This Common Buckeye, which Erika and I found last week at Afton State Park, is only the second eButterfly record for Minnesota, despite the fact the species is relatively common here. See, for example, my previous post on the species. As you add records, you can build your own butterfly lifelist, along with your various  photos, all the while building an overall data base of butterfly distribution.

Friday, July 26, 2013

Twelve-spotted Skimmer and Prince Baskettail

Twelve-spotted Skimmers, like the dragonfly in the upper photo, are common across most of North America, from southern Canada to northern Mexico. We have often seen them during these first three years of watching dragonflies, including in Erika’s garden. I was surprised to discover in Odonata Central that the only record for the species in neighboring Goodhue County lacks specific location data. I have seen Twelve-spotted Skimmers numerous times in the county, and Erika and I set off to remedy this lack of precision during a recent outing on the Cannon Valley Trail.

We failed in our quest. Late in our trip, we did come upon several dragonflies flying high above the trail. They appeared to be Twelve-spotted Skimmers until I looked closely at my photographs. The dark spots on the wings are too small and the wings and the hind winds sport dark “saddles.” At first I thought I had a Calico Pennant, but a skeptical email from Scott King noted that those pennants are not usually found far from lakes and seldom high in the air. Scott suggested that I look at the Prince Baskettail. Voila! The field marks in the lower photo matched perfectly. The range of the baskettail is similar to the skimmer, but is restricted to eastern North America. Mine is a second Odonata Central record  for the species from Goodhue County. Just as in birds, often after you first see a new species, suddenly you see them frequently. Last week, Erika and I found another Prince Baskettail at the Carpenter Nature Center. This Washington County baskettail, however, proved to be remarkably camera-shy as it flitted out over a prairie and back into nearby oak woodlands.

Thursday, July 25, 2013

Bumblebee at Bee Balm

Bee Balm, or Wild Bergamot is in the mint family and grows in fields, prairies, and often in cultivation (where flowers are often bright red). Bees, such as the bumblebee in the photo above, and hummingbirds often feed from the flowers. Wild Bergamot has variety of human uses. It is an major ingredient of Earl Gray tea. Folk medicine used teas from Bee Balm for various respiratory and digestive distresses. The plant also was used by Native Americans as an antiseptic. Bee Balm contains thymol, the active ingredient in many mouth washes. Wild Bergamot has also been used to treat flatulence, headaches and fever (Wikipedia).

Wednesday, July 24, 2013

Cooper’s Hawk

A Cooper’s Hawk at the bird bath is not necessarily good news. This accipiter is moving into subburban and urban habitats—they are small-bird specialists and small birds are often abundant in these areas. They prefer nesting in deciduous forests (the similar, but smaller, Sharp-shinned Hawk nests in forests that are dominated by conifers). The good news is that they also take squirrels and chipmunks, often not loved by birders. Since the mid-1900s, Cooper’s Hawks’ numbers have been on the increase, recovering from shooting and pesticides (Curtis et al. 2006).

Cooper’s Hawks were named in 1828 by Charles Bonapart for the ornithologist, William Cooper. Cooper was the father of James Cooper, for whom the Cooper Ornithological Society is named. The hawk in this blog was photographed in a residential backyard in Aberdeen, South Dakota.

Monday, July 22, 2013

Common Collared Lizard

The Collared Lizard is found with many races across the greater part of the southwest United States and northern Mexico. Erika and I found this one in New Mexico's Mal Pais National Monument.

Collard Lizards are able to run on their hind legs, at speeds approaching 16 mph, allowing them to prey upon relatively large prey, even other lizards. They will also vegetarian, but prefer insects. They tend to be territorial and often bask, like this lizard, on rocks in the sun. When threatened, these lizards quickly disappear under rocks or vegetation. They do not often shed their tails because of predators.

Other lizards can run even faster than Collared Lizards—the world’s record is 21 mph by Spiny-tailed Iguanas (Wikipedia). Alligators are also capable of upright locomotion—perhaps thus responsible for Big Foot sightings in Louisiana swamps.

Saturday, July 20, 2013

Slender Spreadwing

The variation in pattern and color among the dragonflies and damselflies makes them difficult to identify. These are both Slender Spreadwings. Unlike other damselflies, spreadwings hold their wings out at an angle from their bodies. One key to identification here are the barely visible, frosty wing tips—most notable on the upper wings in the first photo and along the lower wings in the second picture.

Slender Spreadwings are common in much of eastern North America. Females lay single eggs in cattail stems. When the emerge, often in large numbers, they are often found in lakeside woodlands and brushy areas (Paulson). The first photo was taken at the Bass Ponds in the Minnesota Valley National Wildlife Refuge and the second comes from Circle Lake in Rice Co., Minnesota.

Friday, July 19, 2013

Lyre-tipped Spreadwing

On 90-degree and humid Tuesday, I ventured down to the River Bend Nature Center near Faribault and photographed this Lyre-tipped Spreadwing. The spreadwings are often difficult to tell apart. The Lyre-tipped has S-shaped paraprocts, little lyre-shapped spikes which I think you can barely make out in the two lower photos. These structures lie under the cerci on each side of the top of the tail. (Lyres are the little harp-like instruments angels play on the streets of heaven.) Note the two red spheres on the “belly” of this spreadwing. These objects are parasitic larval water mites, about which I have previously posted.

Lyre-tipped Spreadwings range across much of southern Canada and the northern United States. They lay eggs in emergent vegetation up to two feet above the water. The eggs can withstand temperatures of −4 degrees F. In colder weather, snow cover protects the eggs.The larvae hatch in the spring when the water reaches 50 degrees. For the next two months, The larvae go through several stages before emerging as adults (DuBois).

Thursday, July 18, 2013

Plains Clubtail

This Plains Clubtail greeted us on a hot afternoon in Carleton College’s arboretum prairie. You can tell it is hot too by the raised tail, obelisk fashion, towards the sun. As its name suggests, the Plains Clubtail ranges widely across the American Midwest. They are partial to muddy streams and rivers, and, although this clubtail was in upland prairie, undoubtedly they breed in and along the nearby Cannon River.

The New York Times recently posted an interesting video of dragonflies. They claim that dragonflies are the planet’s most efficient predators. Lions only capture about 25% of the prey they pursue. Dragonflies kill 95% of their prey! Perhaps not surprisingly, much dragonfly research is supported by the military, which sees the insect as the ultimate precision drone.

Wednesday, July 17, 2013

Kentucky Coffeetree

While at the University of Minnesota Landscape Arboretum, Erika and I spied one of our favorite plants, the Kentucky Coffeetree. The tree’s natural range covers the northern Midwest—Arkansas to southern Minnesota, Wisconsin, Michigan, and New York. Wild coffeetrees are over-harvested and declining (USDA). Another problem is that seeds germinate poorly—their shells are hard and not cached by squirrels. On hypothesis is that coffeetrees used to be germinated by mastodons, whose extinction proved problematic for the tree. This gem is from Wikipedia. The species is occasionally planted by landscapers—they make excellent shade trees, but they are messy when they shed their leaves and seedpods. The trees are, however, fascinating because of their huge, double-compound leaves. In the photograph, one of these leaves arches over the branch with the seed pods.  The “leaves” are actually leaflets. The whole leaf begins at the main branch to the left of the seedpods.

I always knew that coffeetrees owe their name to English colonialists who used the seedpods to substitute for coffee. I did not know that uncooked seeds, pods and leaves are poisonous. The USDA warns, "Clinical signs include rapid onset (within 1 hour) of intense gastrointestinal irritation, profuse diarrhea and straining, vomiting, hypertension, bradycardia, respiratory depression, muscle paralysis, and convulsions. Animals often display depression. Death usually occurs within a day after clinical signs appear.” Exactly which substance make the trees poisonous is unclear.

Boiling destroys the toxin, but there is at least one report of someone dying from consuming parts of a coffeetree. Nevertheless, Native Americans used coffeetrees for a number of remedies. The wood treated insanity, fever, and headaches. Others used it as an appetizer, tonic and laxative. Uncooked beans were thrown into streams to kill fish. Cattle may have died from drinking from pools containing leaves and seeds.

Tuesday, July 16, 2013

Killdeer and Horned Lark

A wide range does not necessarily mean a bird will have multiple races. Killdeer (above) are found from Alaxka to Newfoundland, south to Mexico and from the Bahamas through much of the West Indies. Other breeding populations are found in Costa Rica, Aruba, and coastal Peru and Chile. Across North America, little variation is found—northern birds are a bit larger than southern ones; West Indian breeders are a bit grayer than others. Only one North American race is recognized by ornithologists—Charadrius vociferus vociferus. The South American and West Indian birds are each given subspecific status. But we are warned by Jackson and Jackson (2000) that these non-North American races are of dubious validity; they are only slightly different and require “modern appraisal.”

Compare the Killdeer’s lack of variation with that of another wide-spread North American bird, the Horned Lark. The Horned Lark breeds across most of North America. Body size and coloration vary by breeding location. They superciliary stripe varies from white to yellow. The back color is “strongly correlated with the color of local soil” (Beason 1995). (See also my previous Horned Lark post.) Note the differences between the Horned Larks in the lower photos. The left one was taken this spring near Northfield, Minnesota. The one on the right was in California. Ornithologists divide the species into 21 races, most intergrading into adjacent subspecies. At least two races breed in Minnesota, Eremophila alpestris praticola and Eremophila alprestris leucolaema, the first in most of the state, the second in the far west. Other races undoubtedly visit Minnesota in the winter.

Why the difference in variation in the two birds? A likely hypothesis is that Horned Larks faithfully return to their natal regions whereas Killdeers may be less predictable. As such, the Killdeer may mix genes among themselves at a much greater frequency than do the larks.

Sunday, July 14, 2013

Band-winged Meadowhawk

One of the intriguing aspects of learning to identify odonates (dragonflies and damselflies) is the infancy of the sport. Many odonates are difficult to identify and, until recently, have been to provenance of experts. With a bit of hard work, perseverance, and patient tutelage, most species can be identified. 

Erika and I encountered these Band-winged Meadowhawks at the University of Minnesota Landscape Arboretum. This species was abundant along parts of the arboretum’s auto-route. One fence-line, as you can see in the top photo, served as a perch for several dozen meadowhawks. We had seen this species before at Lake Byllesby Regional Park in Dakota County and I have previously blogged about them. 

Entering our observation in Odonata Central, the on-line dragonfly data base, I was pleasantly surprised to learn that our record on Friday was a first for Carver County! Odonata Central is also a good place to look up identification tips and photos of North American dragonflies. Records submitted to Odonata Central are vetted by regional experts before the sightings are accepted. Odonata Central gives you, as a citizen scientist, the opportunity to add to the scientific data base. 

Saturday, July 13, 2013

Review: Audio Companion for the Warbler Guide

Cornell Ornithology Lab has published audio files to accompany The Warbler Guide, recently reviewed in this blog. These audio files, over 1000, can be played on the mp3 player of your choice. I downloaded them onto my computer and play them with iTunes. (Downloading is trouble-free.) Here is an excellent way to learn warbler calls. Amazingly, The Warbler Guide Companion files only costs $5.99. Although designed to correlate page-by-page with the book, you do not have to buy The Warbler Guide to purchase the companion files.

Study the sonogram in the photo above.  Play the song while you study the sonogram. In iTunes, the sonogram appears as the album cover at the same time the song plays. It is that easy.

These files contain all the species covered in The Warbler Guide. Also included are files on “Understanding Sonograms,” “How to Listen to Warbler Songs,” and “Learning Chip and Flight Calls.” Finally, “The Warbler Guide Audio Companion Booklet,” a short .pdf file, describes sonogram technology and how to use it.

As with the book, birders of all abilities will enjoy these files. They can be purchased and downloaded on line at http://macaulaylibrary.org/guide/the-warbler-guide. The book can also be purchased at that site, or at a bookseller of your choice.

Friday, July 12, 2013

American Robin Sunning

A couple of years ago I blogged about a Great Crested Flycatcher enjoying either the sun (sunning) or ants (anting). On Wednesday at the Bass Ponds in Bloomington, Minnesota, at the Minnesota Valley National Wildlife Refuge, I encountered this American Robin. I noticed no ants, so I assume this bird was sunning.

Birds sun even on hot days. Sunning may convert oil from the uropygial gland into Vitamin D, essential for birds’ health. Sunning may also dislodge feather parasites. Apparently the heated bird body causes the parasites to move, making it easier for the birds to rid themselves of these potentially harmful hitchhikers. If you look closely at these photos, you may notice what appears to be feather lice about midway up the red breast. 

Birds that have recently bathed may also dry themselves by sunning. Birds also seem to enjoy sunning. In the last photo, the robin has closed its nyctitating membrane—in ecstasy? Or was the bird just blinking?

Thursday, July 11, 2013

Eastern Forktail

Eastern Forktails are widely distributed and abundant in the North America—yet I always have found them to be perplexing to identify. Field marks for the male above include the greenish sides of the body and eyes, coupled with the two blue bars on the sides of the blue-tipped abdomen. The first and last photos are taken this summer from Carleton College’s Lyman Lakes. The middle photo, taken in June 2011, is from Carleton’s Lower Arboretum.
Females begin life as orangish bodies (above) but become pruiose (bluish-gray), like the damselfly below. Females only mate once, unusual for damselflies (Dubois). Other females look like males (andromorphs) (Paulson). Larvae go through about a dozen stages (instars) and winter in one of their later stages.
It seems like more often than not, when I encounter a damselfly, it proves to be an Eastern Forktail. This species is found across the northern United States and parts of southern Canada. Eastern Forktails are replaced by Western Forktails across much of the West. The two species are difficult to distinguish—as are several other forktail species.

Wednesday, July 10, 2013

Tule Bluet

Tule Bluets may at first seem similar to the Stream Bluets that I wrote about in my previous post. Note, however, the broader blue rings on the abdomen, rings that become thinner as you look down the abdomen. The first segment is nearly all blue except for the black spot on the top. The last two segments are almost completely blue. Finally, the cerci at the end of the abdomen are white-tipped (see bottom photo).

Duboiswrites that Tule Bluets are found along the shores of “larger, deeper lakes.” Indeed, I found this individual along the shore of Circle Lake, one of the larger lakes in northern Rice County. He also comments that Tule Bluets deposit their eggs on submerged plants and, also, sometimes on rushes even a foot above water. Larvae live for over a year, go through almost a dozen stages (instars), and overwinter in one of their later instars.

The species is common across northeastern and western North America south to Baja California.

Tuesday, July 9, 2013

Stream Bluet

Stream Bluets are abundant damselflies. Pairs and single bluets often hover above creeks, like the small stream that drains Lyman Lakes in the Carleton College Arboretum. Pairs often copulate for and hour or two. Males often remain attached to females as they deposit their eggs, sometimes even ovipositing under water for up to 30 minutes (Paulson).I have previously posted photos of mating Stream Bluets.

This species is identified by its relatively broad, black thorax stripes, mostly black abdomen with thin blue rings, and all blue terminal abdominal segment but black-topped, blue eighth segment. The greenish color on the eyes also serves to identify Stream bluets (see bottom photo). The species is found in eastern North America, the eastern Great Plains, and south into eastern Mexico.

Sunday, July 7, 2013

Savannah Sparrow

I encountered this Savannah Sparrow singing away on top of a road sign at Circle Lake in Rice Co., Minnesota. The species is abundant across much of North America. Alexander Wilson named this sparrow for where the first specimen was collected—Savannah, Georgia.

Annual mortality of adults is around 50% a year. Nevertheless, most Savannah Sparrows return to where they hatched. The result is relative reproductive isolation, which results in marked geographic variation—17 subspecies are currently recognized by ornithologists (Wheelwright and Rising 2008). Birds breeding here in southeastern Minnesota appear to be heavily streaked with relatively indistinct yellowish lores.

Saturday, July 6, 2013

Eastern Pondhawk

The beauty of the emerald Eastern Pondhawk stuck me as I strolled through Erika’s garden last week. These dragonflies are fierce predators (see past post), even consuming fellow odonates. Meadreports that they will even follow people, preying upon their attending mosquitos and blackflies.

Pondhawks are also quite common (even “superabundant,” according to Paulson). Their clutch size averages 900 eggs, all laid in under ten seconds (Paulson). Nymphs must lead a perilous existence, or we would be knee deep in pondhawks. They prefer still water.

Male Eastern Pondhawks start off as relatively dusky creatures. They become pruinose, beginning at the tip of their abdomen, and later, like the one in the last photo, this pruinosity spreads across most of their body.

Friday, July 5, 2013

Four-spotted Skimmer

I have seen Four-spotted Skimmers before, but this is the first from Erika’s garden. On Monday, several flew over the garden. They are fierce predators, even taking other dragonflies. In the garden they definitely behaved territorially, with individuals repeatedly landing on the same stretch of clothesline.

Some males of this species become “satellites” to territory holding males. The satellites are subordinate to the territory holder, but don’t breed unless the skimmers are abundant (Paulson). Field marks include the four spots on the wings and the dark “saddles” at the base of the hind wings.

Thursday, July 4, 2013

Green Heron

A week has passed since I posted a bird photo on my blog—must be the summer doldrums. Add another Green Heron to my collection of photos of this species. We found this individual in the northwest Minneapolis metro area during a recent water garden tour. A relatively good picture (if I do say so), especially considering the distance this bird was from me. As typical for the species, this bird remained at the same spot, as apparently the prey was plentiful.

This Green Heron fed in a manner common to the species. It crouched, with the body horizontal, and with a retracted head and neck. With a lunge, and a strike of its bill, the prey (in this case a bullhead or perhaps a crayfish) was taken in its bill (rather than speared). According to Davis and Cushlan, Green Herons are “carnivorous, typically a fish-eating species, despite comments to contrary in literature. However, prey selection is broad, depending on availability, and includes all sorts of invertebrates."

Wednesday, July 3, 2013

Blue-tipped Dancer

Female Blue-tipped Dancers come in brown (first photo) and blue (second photo) phases. Note the blue tip to their abdomens and, in the blue form, the azure triangle at the rear of the black side stripe. Why do the females come in different morphs? In some damselflies, some females look like males (andromorphs), apparently to reduce male aggression towards them. But, in the case of Blue-tipped Dancers, neither morph looks like the male. One hypotheses is that the two morphs suffer different reproductive and predation rates. If one morph has a high reproduction rate but is often taken by predators, a second morph, with lower reproduction, but less likely to die from predation, may result in both morphs coexisting.
Males (final photo) are a little easier to identify—they are the only dancers with violet, black, and white thoraxes. Notice the male in the last photo is munching on a winged insect. Why don’t males come in two morphs? Scientists suspect that the females are more exposed to predation than their mates (Cordoba Aguilar), thus giving them added advantage to being polymorphic.