Buff-breasted Sandpiper

Sunday afternoon Dave B. e-mailed that he found a small flock of Buff-breasted Sandpipers east of Faribault.  Never having "ticked" this species on my Rice County list, I somewhat belatedly set out in search.  I easily discovered this single bird feeding in a sod farm where the original flock was reported.  This sandpiper often prefers dry, short-grass habitat.

Buff-breasted Sandpipers breed sporadically across the western Canadian and Alaskan Arctic shores and into western Arctic Asia.  The Asian birds presumably migrate with the North American ones to the pampas of Argentina, Uruguay, and Paraguay.  They migrate over the central United States. The species seems to be fairly picky about its habitat.  I have observed this sandpiper only about a half dozen locations.  Erika and I saw them regularly in Louisiana, but only in the same well grazed pasture in Cameron Parish.  We encountered them on a grass DC 3 landing strip in the Amazonian Ecuadorian jungle. I saw them twice in South Dakota, once along a weedy drained shoreline and once in grazed pastureland.  Finally, I have found them twice in Minnesota, both times in sod farms.

The first time I saw these birds in South Dakota we found a flock of several hundred in May.  Despite their migrating, the males were already displaying.  Buff-breasted Sandpipers have bright white under-wings.  Males display by extending one or both wings, trying spasmodically to flag down the interest of females.  This species are the only North American breeding shorebird to breed on leks.  Males defend small display sites.  Females pick the sexiest mate and then nest elsewhere without male assistance.  Check out this video.

Once abundant, Buff-breasted Sandpiper numbers have greatly declined since the late 1800s.  Grassland habitat in the United States and in southern South America has gone under the plow.  Before the Migratory Species Act, this sandpiper was also commercially hunted.  Buff-breasted Sandpipers are usually tame and have the unfortunate habit of returning to wounded flock members.  Despite legal protection, recent surveys suggest the species is still declining.  The Handbook of Birds of the World estimates the total world population to be no more than 25,000.  In contrast, the Stilt Sandpiper, which has a similar migration route but different habitat preferences, enjoys as many as 100,000 individuals.  (I am not exactly sure how these estimates are made.)

Eastern Pondhawk

My dragonfly stalking began this fall.  This Eastern Pondhawk is the fifth species I have found in our garden. This fierce predator eats anything it can catch, including other dragonflies. The species is common over much of eastern North America.

Red-eyed Vireo

Back on 18 June 2010, I posted a photo of an adult Red-eyed Vireo showing its red eye.  I promised to look for an immature bird.  I caught this one last Thursday--a brown-eyed Red-eyed Vireo.  Age is told by eye color.  Perhaps the brown eyes reduce aggression from red-eyed adults, indicate breeding condition or readiness, or perhaps just identify young vireos.

Mourning Warbler

On Thursday I was surprised to band a fairly bright Mourning Warbler. Usually by now both sexes would be in their drab fall plumages. Little is known about the breeding biology of this warbler.  One reason is that this species prefers tangles and thickets and so is hard to observe.  Because of its predilection for dense habitat--the sort that often appears after lumbering--the Mourning Warbler is one of a few of our neotropical migrants that may be more common now than in relatively recent history.

Golden-winged Warbler

On Thursday I banded a Golden-winged Warbler, our first for the Dundas banding site. I previously observed the species there but never banded it.  In my 14 June 2010 blog, I discussed some of the genetics and population dynamics of this bird.  But this warbler has more fascinating biology.

I caught this Golden-winged Warbler with four Black-capped Chickadees, perhaps not a coincidence.  These two species are often found with each other, especially in the late summer and during the fall migration.  This association may be to the benefit of both species.  The warbler learns from the resident chickadees where the best feeding areas are located (and the chickadees are familiar with local predators).  The warbler may be better able to open insect-laden buds that the chickadee would otherwise miss (the chickadee then steals from the warbler).  The somewhat similar plumage of the two species (black throats, gray bodies, and similar song pitch) may reduce aggression and thereby enable the species to occupy the same flocks (Eastman, Birds of Field and Shore).

Autumn Meadowhawk

Autumn, or Yellow-legged Meadowhawks are common dragonflies across much of North America. This dragonfly is the fifth species of Odonata that I have found in our backyard.  I am amazed at their crimson eyes. The meadowhawk in the photo above is an immature male.  It will become brighter red as the season progresses.  The photo below is of a female.  The yellowish legs and the downspout ovipositor are good field marks.  Thanks to Scott King for identification help.

Black-throated Green Warbler

The parade of confusing fall warblers continued on 24 August, when I banded this first-year fall Black-throated Green Warbler.  The male (see below) is one of the more handsome of the spring birds.  Fall males have more black on their throats than this female, which also showed a yellowish wash on its lower flanks.

The Black-throated Green Warbler's spring song is distinctive and easily learned by beginning birders.  On its northern breeding grounds, one male sang 466 songs in an hour.  This species is thought to be monogamous.  Silent males, however, have been observed within another pairs' territories, which may indicate that extra-pair copulations occur (Morse and Poole 2005). Genetic testing of siblings would indicate if such shenanigans were taking place.

Spreadwing Species

I have just begun chasing dragonflies around the backyard and am finding them exceedingly difficult to identify.  I am somewhat confident that the damselfly in this post is a species of spreadwing.  According to the Mississippi National River and Recreation Area website, the distributions of the Minnesota spreadwings and damselflies are not well known.  At least six species might be found in this region of the state, but identification requires closely examining a captive.  Whatever species this may be, I was amazed by the intensity of its azure eyes and by the yellowish racing stripe along its sides.

Resting spreadwings hold their wings back in a V-shape, unlike dragonflies that hold their wings straight out and damselflies that keep their wings against each other. Unlike most dragonflies that survive as larva under water during the winter, some spreadwings inject their eggs into vegetation just above the waterline.  In winter, the eggs go into a suspended state. After winter, as water levels rise, the eggs begin growing again.  Thus spreadwings are among the first dragonflies to appear in the spring.

Since posting this blog, I received a note from Scott King.  He writes "The spreadwing is even more exciting. I'm fairly certain it's a Great Spreadwing (Archilestes grandis) and a new state record...The closest records for this species are for Iowa and are from August and September. Take a look at the dot map for the species at Odonata Central (http://www.odonatacentral.org/): type in Archilestes grandis for the taxa. It's a significant find. One reason for recent survey work is to document range expansions to the north due to climate change; this would certainly suggest such an expansion.

White-faced Meadowhawk

White-faced Meadowhawks hunt near the forest edge from low perches usually near streams or ponds. Fifteen species comprise the genus Sympetrum, and many are difficult to distinguish.  This species, obtrusum, is identified by its white face and the black diamonds on the red tail. This meadowhawk is found across much of northern North America. It is a late season dragonfly, observed in Minnesota even in late November. These dragonflies eat most soft-bodied insects, including mosquitoes, flies, small moths, mayflies, and flying ants and termites.

Jack-in-the-pulpit

Many folks are familiar with Jack-in-the Pulpit (Arisaema tryphyllum), which gets its name from the spadix that looks like a preacher in a pulpit (see Erika's photo below).  The spadix contains tiny flowers. Fewer people know the bright red fruit, which appear in the fall as the foliage withers.  In the photo above, the fruit is changing from green to a ripe crimson.

If properly prepared, the Jack-in-the-Pulpit is edible.  But beware--the plant contains calcium oxalate, which can create burning sensations and rashes, irritate the digestive system and adversely affect breathing.  Native Americans used the plant to treat rheumatism, bronchitis, asthma, snakebites, and to induce sterility. On the other hand, 17th century Europeans thought plants were put on this earth with signs for how humans should use them.  (The liver shape of liverworts was a sign that these plants could be used to cure liver ailments.)  The Jack-in-the-Pulpit's spadix was seen as a sure sign that the plant is an aphrodisiac.  The Minnesota Department of Natural Resources wisely considers the Jack-in-the-Pulpit to be toxic.