Sunday, December 30, 2012

Barred Owl

Erika and I enjoyed today's Red Wing, Minnesota, Christmas Bird Count. The good news: a beautiful, sunny day. The bad news: temperature was 0 degrees F. I made squeaking sounds to attract a flock of chickadees, but, instead this owl flew up to investigate. The lack of "ear" tufts, large size, and dark eyes add up to Barred Owl. Note the odd, white, fluffy feathers above the eyes--perhaps downy feathers on a bird hatched this year?

Other notable birds of the 23 species we listed included two Golden Eagles and 17 Mourning Doves.

Friday, December 28, 2012

Hudsonian Godwit

In the early 1900s, Hudsonian Godwits were thought to be among the rarest of North American birds. In the last half of the century, however, new breeding areas in the Canadian and Alaskan Arctic, staging areas in Saskatchewan, and wintering grounds in southern South America were discovered. Walker et al. (2011) warn that the species is still at risk, with total numbers only of 50,000 to 70,000 birds.

Hudsonian Godwits make nonstop migratory flights of several thousand miles. Possibly birds make landfall at traditional sites. One of these may be the Aberdeen, South Dakota region, where I regularly listed Hudsonian Godwits in the spring and where this photo was taken.

Wednesday, December 26, 2012

Upland Sandpiper

The late 1800s and all of the 1900s were tough for Upland Sandpipers. At first the birds were over-hunted. Boxcar loads of carcasses were shipped to bird markets. Sport hunters also took a high toll, since no seasons or limits existed. Perhaps more ominously, Upland Sandpipers are an “obligate grassland species” (Houston et al. 2011). To raise their young, these birds require healthy prairie-lands. Such habitat has been plowed for agricultural and financial purposes (even today, plowed land is often worth more when ranchers are forced to sell their acreage). Now they are a species of concern in at least 22 states and provinces.

Upland Sandpipers breed across the northern Great Plains (this photo was taken in south-central South Dakota). They also breed in Alaska and in northeastern North America. The sandpipers are rare in the northeast due to lack of prairie. There one of the best places to search is the grass along airport runways. I saw my first Upland Sandpiper from a plane at the Columbus, Ohio, airport. In South Dakota the species is fairly common in grassland habitat and it is only locally common across western Minnesota. Our birds winter in South America east of the Andes. (Birds spend more time outside North America, so calling them “ours” may be misleading.)

When I first saw this species in Columbus, we called it the Upland Plover, even though everyone knew it is actually a sandpiper. The common name actually has quite a history. In 1882 it was known as a Bartramian Tattler (commemorating William Bartram, an early American ornithologist; and tattler referring to a type of sandpiper). Later the same decade, the name was changed to Bartramian Sandpiper. Between 1910 and 1973, the official name became Upland Plover. Only since 1973 has the species been known as Upland Sandpiper (Houston et al. 2011).

Monday, December 24, 2012

Barn Swallow

I took a few Barn Swallow photos this summer. The first is of a male along Cannon Lake near Faribault, Minnesota. The photo is somewhat serendipitous—I was standing there with my camera and the bird was perched on a nearby dock. So I took the photo. At the time, I did not notice the beak was full of nesting material—probably a mud pellet mixed with grass. (I also did not notice the spider web hanging from the right wingtip.) Both sexes build the nests, which may contain up to 1400 pellets (Brown and Brown 1999). The inside of the nest is often lined with grass, horsehair, feathers, and/or lichen.
The next photos were taken later in the summer at the University of Minnesota Landscape Arboretum. The middle bird is probably a female, but, in any case, well-worn after a summer’s work. She patiently waited for Erika and me to pass, before returning to her nest. Although males help at the nest, females usually do most of the work. Nest building takes a week or two. These swallows will often use nests from previous years. Nest refurbishing only takes about a week. Some nests from Nebraska are reported to be up to 17-years old (Brown and Brown 1999)!

Saturday, December 22, 2012

Black-throated Gray Warbler

Only three records for this warbler in the Dakotas or Minnesota are depicted on eBird maps. This bird breeds in the Pacific Northwest, the American Southwest, and in the intervening western Rocky Mountains; it winters in Mexico. Within its range, this warbler prefers pinon-juniper, pine and mixed oak-pine forests. In September 1986, George Prisbe and I found an out-of-range individual in a city park in Aberdeen, South Dakota. This photo was taken years ago in the Organ Pipe Cactus National Monument of southern Arizona.

Thursday, December 20, 2012

White-winged Crossbill

On Monday, John Holden and I were excited to band this female White-winged Crossbill. Although these crossbills often travel in flocks, we only saw this one. The bird flew confidently into the feeding station, looked around, and calmly walked into one of my banding traps.

These crossbills are highly nomadic. They travel in search of conifer cones. They use their crossed bills to efficiently open cone scales. Single birds can eat up to 3,000 conifer seeds a day, although Benkman (2012) also comments that crossbill cone-opener bills make them “much less efficient than other finches at exploiting non-conifer seeds."

White-winged Crossbills normally breed across northern Canada. They are, however, unpredictable migrants and opportunistic breeders. They will breed at almost any time of the year if the birds find abundant conifer cones. One year Jacob Langslag and Jon Little even found a pair breeding in Rice County—the only confirmed breeding record from Minnesota!

Tuesday, December 18, 2012

Prairie Warbler

About the most uncommon bird I have banded in Minnesota is the Prairie Warbler.  Eckert writes that the species is casual in southeastern Minnesota, with only about a dozen records. I caught this one near Dundas very early on the morning of 13 May 2009.  (The black backgrounds here and in my last post were due to the birds being flash-photographed early in the morning or at dusk.)

This bird is found in the East, with the closest normal breeding occurring in Illinois and Arkansas. The species usually inhabits abandoned fields with young pines or cedars. Originally Prairie Warblers were not common birds, but the species benefited from deforestation. Since 1970, however, the numbers have dropped, perhaps due to Eastern urbanization, reforestation, and/or habitat destruction in its Caribbean winter range (Nolan et al. 1999).

Sunday, December 16, 2012

Worm-eating Warbler

Worm-eating Warblers breed in the southeastern United States and winter in Central America.  As near as they get to the Upper Midwest is usually in the Ozark Mountains of Arkansas. Yet in my 30 years in Aberdeen, South Dakota, I banded this species twice, once on 2 May 1988 and again on 9 May 2005. The species is rare in southeastern Minnesota, with most records in May (Eckert). Presumably these spring birds are over-shooting their normal breeding range. Caterpillars, once known as “worms,” comprise the bulk of the Worm-eating Warbler’s diet: hence this warbler’s name (Hanners and Patton 1998).

Thursday, December 13, 2012

Yellow-crowned Night-Heron

Yellow-crowned Night-Herons are easily identified as adults, but see my last post on telling the immatures apart. Typically Yellow-crowns are birds of the south, inhabiting forested wetlands, swamps and bayous. There they specialize in taking crustaceans. Since 1945, Yellow-crowned Night-Herons have moved northward and now can occasionally be found here in the Upper Midwest. Curiously in the mid-1800s they could be found here too, but the species’ range contracted dramatically in the late 1800s (Watts 2011). The causes of these population fluctuations are unknown. This photograph is from the Ding Darling National Wildlife Refuge in Florida.

Wednesday, December 12, 2012

Black-crowned vs Yellow-crowned Night-Heron

The Black-crowned Night-Heron is another widespread, common North American heron. We saw them more often when we lived in South Dakota then now in Minnesota. Especially away from their breeding colonies, these birds can be hard to locate—they tend to be nocturnal. Populations are reduced now compared with years past—they are top-level predators (eating mainly fish and whatever else they can capture) and tend to accumulate poisons in their tissues. DDT contamination led to population crashes in the 1960s; now wetland destruction threatens them. On the other hand, these night-herons are not picky about their choice of breeding locations and will tolerate human disturbance (Hothem et al. 2010).

Adult Black-crowned Night-Herons are not difficult to identify. Notice the tear-drop shaped stripes on the immature bird in the next photograph. Also the head is relatively large and the body shape is stocky. Birders often have trouble telling the immature birds from young Yellow-crowned Night-herons
The last bird is a young Yellow-crowned Night-Heron. Its back is more spotted than tear drop-shaped. Its head is slightly smaller and it appears to be longer-necked. I will post a photo of an adult Yellow-crowned Night-Heron in my next post.  Both of the Black-crowned Night-Herons in this post are from South Dakota; the Yellow-crowned Night-Heron is from the Everglades National Park in southern Florida.

Monday, December 10, 2012

Harlequin Duck

Harlequin Ducks breed and feed in the turbulent white water of mountain streams of Labrador, Newfoundland, and the Rocky Mountains of Northwestern North America. After copulating, the males retire to the North Pacific and North Atlantic oceans, where they loaf around until they are joined by the females and young late in the summer. The Upper Midwest is definitely out of this species’ range. Yet I have seen this duck in South Dakota and Minnesota. This photograph, taken a couple of winters ago, is from Prescott, Wisconsin, where a male (the same individual?) appeared for several winters. In Minnesota, Harlequin Ducks are more often seen along Lake Superior. Where did these birds breed? Because eastern populations are quite low—perhaps under 1500 birds—a good guess would be these birds are from somewhere in the Northern Rocky Mountains.

Saturday, December 8, 2012

Northern Hawk-Owl

Looking through my blog, I am surprised I have not discussed the Northern Hawk Owl. This owl is rare but regular, mostly in northeastern Minnesota. They can be hard to find during years when they have not irrupted out of northern Canada, but good numbers can be seen when they invade. In 2001, I observed seven during a single afternoon. A few nesting records exist for northeastern Minnesota bogs (Eckert).

Hawk owls breed in northern forests of both the Old and New Worlds. Nevertheless, they are one of the least studied birds of North America. Almost no nests have been studied on our continent. These birds are atypical among owls in that they feed during the day and, in many ways, resemble Accipiter hawks. They often perch atop prominent trees. Unlike other owls, where the females are larger than males, hawk owl sexes are similarly sized.

Hawk owls can locate prey under up to 30 cm of snow cover (presumably by sound). Their invasions of southern areas are thought to be after periods of high reproductive success followed by severe winters with relatively few prey, but little is known about these population swings. These owls consume small rodents, grouse, ptarmigan, and rabbits (Duncan and Duncan 1998).

Thursday, December 6, 2012

Least Bittern

Several years ago in South Dakota, a friend called and invited me on a birding trip to search for Least Bitterns. The problem is that, in the upper midwest, you don’t see that many Least Bitterns. It is not that they are rare—they can be quite common—nor are they particularly shy. They are extremely inconspicuous in their deep-water marshland habitat, and they are the smallest of the herons. If you get too close, they will often “burrow like rodents through dense vegetation”—they have extremely narrow bodies—or stand completely still with their beaks in the air and their feathers tights against their bodies (Poole et al. 2009). Only rarely will they fly—although I have seen roadkill on occasion in South Dakota and birds in flight in the winter in Louisiana.

Thus finding this Least Bittern was quite a surprise. It fed quite unconcerned about our presence in a marsh in Sand Lake National Wildlife Refuge near Aberdeen. The bird stood perfectly still and then, in a flash, speared a small catfish. Where prey is abundant, Least Bitterns also build small platforms from which to feed. Satiated, this individual strolled deeper into the marsh, leaving my friend and me delighted with our discovery.

Tuesday, December 4, 2012

White-lined Sphinx Moth

Yesterday I noticed something protruding from our garage light. Closer examination proved it to be a mummified White-lined Sphinx Moth. Extracting it from the light fixture damaged the thorax, but the moth was, nevertheless, beautiful.

This insect, often called a hummingbird moth, does not overwinter in Minnesota, but migrates, after massive population buildups, north in the summer. They feed in the evening, dawn, and at night (Restoring the They feed on a variety of plants and are not specialists, although they are fond of Evening Primrose. The species is found across the United States and adjacent Canada south through Central America. They usually do not harm garden plants, but, in periods of overpopulation, these moths’ caterpillars have damaged crops like tomatoes and grapes (Butterflies and I have previously found these caterpillars in Northfield and have posted about them. Finally, these moths are attracted to artificial lights, like that in my garage.

Sunday, December 2, 2012

American Bittern

Eckert rates American Bitterns as uncommon throughout Minnesota, mostly in the west and western northeast. The bitterns I have seen or heard in the state have been in the Boundary Waters.  Bitterns are more common in eastern South Dakota, where I took this photograph. They also breed across the northern United States and southern Canada, where they inhabit wetlands with tall marsh vegetation. They are, therefore, often easier to hear than to see. They have trouble finding each other too, and locate each other with their unbird-like, loud, thunder-pumping calls (link courtesy of Thayer Birding Software).  Folk names for the species include "thunder-pumper” and “stake-driver” (Lowther et al. 2009). These authors comment, "because of this species’ secretive nature and inaccessible habitats, remarkably little is known about the basic aspects of its biology…” On the other hand, if surprised by observers, bitterns will occasionally freeze or play dead. American Bittern numbers are declining, mostly due to habitat degradation and destruction.