Tuesday, November 29, 2011

American Wigeon

This photograph, another of my series of duck pairs, was taken on 17 March 2009 on Wells Lake near Fairibault, Minnesota. The ducks are American Wigeons, which we once identified as Baldpates. The spring male, with its white cap, is distinctive. Females and fall males are often best identified by their rusty-brown sides.

Wigeons breed further north--from the Bering Sea to Hudson Bay--than most other dabbling ducks. The breeding range dips down to western Minnesota and the Dakotas. Pairs form on their wintering grounds across the southern United States, Mexico and Central America. Males abandon their mates after the females are well into incubation, when the males retire to larger lakes to molt.

American Wigeon are mainly vegetarian. They often graze in agricultural areas. They are aggressive, opportunistic foragers. On the water these poor divers often associate with American Coots and diving ducks, robbing both of plants brought to the surface (Mowbray 1999).

Sunday, November 27, 2011

Pine Siskin

On 22 November 2011, a large, mixed flock of Pine Siskins and American Goldfinches descended on our bird feeders. I banded 27 (10 siskins and 17 goldfinches). The siskins were the first of this fall at our home. The next day the flock vanished.

Last December, I wrote about siskins, “ During my 25 years of banding in Aberdeen, South Dakota, I banded 13,239 Pine Siskins,more than any other single species and despite their being absent during somewinters. Some summers, after abundant winters, siskins bred in the area.Two recoveries illustrate their nomadic nature--one banded in Aberdeen on 10March 1985 was found in Connecticut on 11 March 1988; another Aberdeen siskin,banded on 12 December 1992 was recovered near San Francisco, California, on 5January 1995."

What is responsible for the irruptive nature of this species? Presumably regional failures of conifer cone crops and fruiting trees such as aspens cause these irruptions (Dawson 1997). The problem is the difficulty in estimating relative tree seed numbers versus siskin populations.

Friday, November 25, 2011

Red-tailed Hawk

Last Monday, Erika sat in our sunroom that looks out over our bird feeders and backwoods. She watched a Short-tailed Shrew repeatedly run from under the leaf litter to collect fallen sunflower seeds beneath the feeders. Erika went in search of our camera, which, of course, I had in the car with me. She returned to watch the shrew when, from above our home, a Red-tailed Hawk dropped on the shrew. The hawk carried the shrew to a nearby tree bough, and swallowed the shrew with one gulp. Earlier this month, a Red-tailed Hawk (the same individual?) carried off from the feeder what appeared to be a Red Squirrel.

According to Preston and Beane (2009), Red-tailed Hawks mostly prey upon mammals (mice, ground squirrels, and rabbits), birds (mostly pheasants and quail), snakes, and also, rarely, small birds.  These authors cite a Wisconsin study of the winter diet as 44% cottontails, 28% voles and mice,, and 10% Ring-necked Pheasants. In the spring, Red-tailed Hawks consumed 38% cottontails, 23% Ring–necked Pheasants, 14% squirrels and muskrats, 10% passerines and other small birds, and only 7% voles and mice.

The Red-tailed Hawk in this photograph is a stand-in for our recent sighting.  I took this photograph several years ago near Pierre, South Dakota.

Thursday, November 24, 2011

Banding and eBird

I continue to be fascinated by eBird. I am now keeping daily records of the numbers of birds I encounter (along with date and location). I am looking back at my bird records to see what could be entered into eBird. I hate to admit that many of my bird lists simply record new birds for the year, without precise locations. An exception is my banding records. With data files from the Bird Banding Laboratory, I have begun entering these data into eBird.

I began banding at the tender age of 20; my first bird, an Ovenbird, was ringed on 14 October 1967. Since then, I have banded 71818 individual birds! The list would be even longer, except that my banding during my college years tended to be a bit spotty (my first serious banding project was in 1970, when Erika and I did a senior project studying the ecology of William's Spring in Arizona's Organ Pipe Cactus National Monument).  Then an eight-year hiatus spans our graduate years--we were too busy studying and chasing around Peru and Ecuador.

The bird in the photograph is of a Common Yellowthroat banded this past spring near Dundas, Minnesota.  Like the banding data I am entering into eBird, this photo is somewhat serendipitous.  I have just been waiting for a chance to publish it.

Monday, November 21, 2011

Greater Roadrunner

Another bird of the American southwest and the last of our fast-food bird-list species (see previous two posts), Greater Roadrunners are aberrant, ground-running cuckoos. This one foraged in the bushes of a McDonalds in Catalina, Arizona. The roadrunner is an opportunistic predator, feeding on "snakes, lizards, spiders, scorpions, insects, birds, rodents, and bats, which it beats repeatedly against a hard substrate before consuming. During severe food shortages, it may eat its own young" (Hughes 2011). Why Greater Roadrunner? A second species of roadrunner, the Lesser, is found in Mexico.  As you can see in the photograph below, which I took in Antiqua Morelos in Tamaulipas, Mexico, in July 1964.  The Lesser Roadrunner is smaller and less streaked below than its northern cousin.  The two species overlap, but don't interbreed, in central Mexico.

Saturday, November 19, 2011

Cactus Wren

The Cactus Wren is often one of the most abundant birds in southwestern deserts. In Arizona, they may fledge up to three broods a year. They find enough liquid in their diet of "insects, occasional small reptiles or amphibians, seeds, juicy pulp from cactus fruit..., and juice from wounds in cactus" (Proudfoot et al. 2000). Add to that list, McDonald's french fries, as this bird ate them at a parking lot in Calalina, Arizona. Check another species to our fast food bird list. Despite tolerating human disturbance, populations in the southwest are declining with loss of native vegetation.

Thursday, November 17, 2011

American vs. Lawrence's Goldfinch

The American Goldfinches at the feeders are in drab winter (basic) plumage. I took the photo above of a spring bird that, except for a few gray crown feathers, is almost molted into bright summer (alternate) plumage. The patches of gray on spring birds throw some beginning birders into thinking they have Lawrence's Goldfinches (see the lower photo),
a bird named in 1850 by John Cassin for George Lawrence, a New York businessman and naturalist. When these are reported to me, I reply "Look at the range map." Lawrence's breed in the foothills of California and northern Baja California. They winter in Arizona, New Mexico and occasionally into western Texas, and northern Mexico. Both in summer and winter, this goldfinch's range is erratic and unpredictable. They are seen one year but not the next. Birds have accidentally wondered to Nevada, Colorado, and Oregon (Davis 1999).

This species is one of the few birds on our McDonald's parking lot birdlist. (In upcoming posts, I will share a couple more birds on that list.) On a winter road trip through Arizona, we stopped for lunch near Florence. I crossed the street and easily identified a small flock of Lawrence's Goldfinches. Really these birds are quite distinctive and should not be confused with the much more widespread American Goldfinch.

Tuesday, November 15, 2011

Deformed Black-capped Chickadee


On 14 November 2011, we banded a hatching-year, deformed Black-capped Chickadee near Dundas, Rice Co., Minnesota. I immediately recognized that this condition is similar to a situation reported in two 2010 papers published in The Auk, the journal of the American Ornithologists' Union ("Epizootic of Beak Deformities among Wild Birds in Alaska: an Emerging Disease in North America?" by MulCahy et al. [Auk 127(4):882-298, 2010) and "Beak Deformities in Northwestern Crows: Evidence of a Multispecies Epizootic" by Hemert and Handel [Auk 127(4): 746-751].) (This individual was retrapped on 28 November 2011.)

Over the past decade, Alaskan researchers have documented 2,160 Black-capped Chickadees and 435 other birds of 29 species with grossly deformed bills. High incidences of Northwestern Crow beak deformities were later reported from Vancouver, BC, and the Seattle area of Washington. Most of these birds were over 6 months old, suggesting "either a latent development or an acquired condition." The cause of this unusual concentration is unknown. Along with the beak, birds also showed lesions in other keratinized tissues of the skin, legs, feet, claws and feathers. (Note the bald areas around the eyes in my second photograph. Some feathers in my first photograph seem to be sparsely barbed).

Beak deformities are to be expected. Years ago near Aberdeen, South Dakota I photographed the Red-winged Blackbird below. Note its long lower mandible. The Alaskan researchers are alarmed at such a large cluster of abnormalities. In the 1970s, high rates of crossed mandibles were reported from aquatic birds around the Great Lakes and high levels of organochlorine contaminants were documented there. In the 1980s high levels of selenium from agricultural runoff in California produced similar effects in birds.

The beak deformities, abnormal feathers, and skin trouble suggest this situation may be a systemic keratin problem. A number of factors, including vitamin A and/or D deficiencies, might cause these symptoms. Seed-based diets are usually deficient in vitamin A and calcium. High-fat diets, common at bird feeders, can also interfere with calcium uptake. Remember, however, that the cause(s) of the Alaskan and Pacific Northwestern outbreaks remain a mystery. Hopefully this disorder is not the result of pollution or an infectious bird disease, and our deformed chickadee is just an isolated case. Birders should be on the lookout for other deformed birds.

Monday, November 14, 2011

Acrobatic Red-bellied Woodpecker


This species' red belly is often hard to see--so perhaps this post should be titled Exhibitionist Red-bellied Woodpecker. While walking in the River Bend Nature Area in Faribault, Minnesota, (on 11 November 2011), Erika and I discovered this woodpecker upside-down at the very ends of Hackberry tree branches. We've seen another woodpecker species acrobatically balancing while eating Hackberry fruit. Remember my post of similar behavior by Pileated Woodpeckers? You often see Red-bellied Woodpeckers foraging like normal woodpeckers in forests or at feeders. Shackelford et al. (2000) are certainly correct when they state that this woodpecker is a "generalistic and opportunistic feeder." 

Saturday, November 12, 2011

Red-spotted Purple

The Red-spotted Purple is polymorphic, which means it comes in two forms. These different patterns used to be considered separate species. The second morph is named the White Admiral. Red-spotted Purples occur south of a line from central New England, Michigan and Minnesota. White Admirals are found north of the line. Where the two forms meet, massive hybridization occurs. Last March I blogged about such a hybrid.

Red-spotted Purples mimic poisonous Pipevine Swallowtails. Adult Purples eat sap, rotting fruit, dead animals, dung, and small white flowers (Wisconsin Butterlies.org). The butterflies in my photos, taken last summer, were sipping bikers' sweat on a bench along the Cannon Valley Bike Trail.

Thursday, November 10, 2011

Hophornbeam

In July, Erika and I came upon this fruiting American Hophornbeam (also known as Eastern Hornbeam or Ironwood) along the Cannon Falls city bike trail. This species, often in the forest understory, is found across much of eastern North America, but the tree is not commonly cultivated because it does not tolerate pollutants well (like road salt), grows slowly, and does not transplant easily. This member of the birch family can grow up to 30 feet. The word hop comes from the fruits' resemblance to hops that are used in brewing beer. Hornbeam refers to a similar European tree whose wood was used to make oxen yokes (the wood also is used to make fine fence posts and tool handles). Hophornbeam buds, catkins, and fruits are important food for grouse, turkeys, Purple Finches, grosbeaks, Downy Woodpeckers, and a variety of forest mammals (USDA).

Tuesday, November 8, 2011

Book Review: National Geographic Birds 6th Edition


Last October I reviewed a few of the major bird field guides. This month the National Geographic Society has come out with a new, sixth edition of their Field Guide to the Birds of North America. At first glance, this book will appear to be similar to previous editions. A closer look will confirm that this conclusion is in error. This edition includes new illustrations and text, better identification tips, and features that make the book easier to use--amounting to a must-have volume for birders of all abilities.

Three hundred new illustrations appear in this edition. The number of extremely rare birds increases from 71 to 92. Rare birds are of little use to those of us who will never visit the Aleutian Islands and, in fact, may lead beginning birders astray. I would have preferred more illustrations of more common birds. As in previous editions, at least five artists have contributed to the plates in this book. This gives the illustrations more variability than the uniformly excellent artwork in the The Sibley Guide to Birds. For example, I dislike the backgrounds behind many of the sparrow plates, backgrounds that distract from the species and add little or nothing to aid identification. I suspect having both books will give birders multiple impressions of different species, and this diversity will aid in identification.

Field mark text-labels along side most of the illustrations, often with pointers to key field marks, make this volume more effective for species identification than previous editions. The plates in this new work achieve a parity with Sibley's work. Range maps have been updated and improved. Now the maps use six, rather than three colors, imparting more range information. For better or worse, extralimital distributions (shown as green dots in Sibley's book) are not included here. In an appendix, 59 range maps show the distribution of many field-identifiable subspecies. This feature, along with attention to subspecies throughout the book, brings birding to an almost full circle begun by early editions of Peterson's field guides that included subspecies. Subspecies information is essential in these days of flux in our understanding of avian taxonomy. You never know if a subspecies today will become a full species tomorrow.

The Geographic guide now includes 990 species (compared to 810 in Sibley). Despite these additions, this new book has smaller dimensions than Sibley's, making it hefty, but more portable in the field. One reason for the smaller size may be that the Geographic book averages about three illustrations per species compared to eight in Sibley. Exceptions, however, can be found for many species.

An illustrated index to bird families occurs inside the front and back covers (similar to family reviews found in Sibley). A new feature in this guide is inclusion of dictionary-like tab indentations along the book's outer edge aid in finding selected bird families. Unfortunately only seven families are tabbed, leaving the novice user to struggle to find untabbed families such as owls, woodpeckers and hummingbirds. The bottom line? This field guide is excellent. It stands alongside its strongest competitor, the The Sibley Guide to Birds. Birders will want both. Owners of older editions of the Geographic guide will be happy with this upgrade.

Monday, November 7, 2011

Fish Crow

Two years ago, I took this photograph of a Fish Crow in the Merritt Island National Wildlife Refuge on the east coast of Florida. Since I previously bogged on American and Northwestern crows, I thought I would write a short note on Fish Crows. Fish Crows are hard to differentiate from American Crows--Fish Crows are smaller and have a similar, but more nasal call.

Fish Crows are found from southern New England and along the Atlantic and Gulf coasts to Texas. To my surprise, Fish Crows are also found up the Mississippi Valley to St. Louis, with vagrants even found in southern Ontario.  Throughout its range, this species has been expanding northward, with new colonies being formed often far from the previously know northern limits of their range (Mcgowan 2001).

Because Fish Crows often nest in cities and Minneapolis is on the Mississippi, I believe our city is a potential host to this small corvid. I have observed crows in Minneapolis that I would have identified as Fish Crows had I been aware of the possibility of discovering them here. One was a noticeably small crow that did not appear to be a young bird. I have also heard crows that sounded like Fish Crows. Both these field marks are notoriously subtle. The following links take you to American Crow calls and Fish Crow calls. (These files are used with permission of Thayer Birding Software's Birds of North America.) Young American Crows can sound like Fish Crows. The bottom line is that I am not sure how one might verify a Fish Crow's occurrence in Minnesota.

P.S. Alan Wormington, on the Ontario Bird Records Committee, writes, "Fish Crows are not accidental in southern Ontario.  We have 23 records, including one suspected nesting record."  

Saturday, November 5, 2011

Red-breasted Nuthatch

I previously blogged about Red-breasted Nuthatches on 6 October 2010. John H. and I found an inquisitive flock of about a dozen nuthatches at Crex Meadows, an area I wrote about in my last post. These birds readily investigate squeaking noises made by birders. The bird above is feeding in a typical up-side-down nuthatch fashion. I think its odd white crown is an artifact of the lighting in the photograph--we did not notice it in the field. We were serenaded the whole time by the nuthatch's "yank-yank-yank" call. (This file is used with permission of Thayer Birding Software's Birds of North America.)

As I mentioned in the 2010 post, Red-breasted Nuthatches tend to irrupt irregularly out of the North Woods. These movements can cover great distances, in some years all the way to the Gulf Coast. This species has even accidentally flown all the way to Europe. This ability to disperse results considerable genetic mixing among North American nuthatches. Consequently, ornithologists are not able to differentiate races among these populations.

Thursday, November 3, 2011

More Sandhill Cranes

After talking about a trip to Crex Meadows for about a year, John H. and I finally visited on 1 November. This wildlife management area is run by the State of Wisconsin. This 30,000 acre, marshy ecosystem is the largest remaining tract of the Wisconsin Pine Barrens. The area hosts a plethora of birdlife and is a breeding and staging area for Sandhill Cranes.
Crex Meadows charges no entry fee. Do not miss the 24-mile Auto Tour Route and the short boardwalk and hiking paths at the headquarters. The visitor center is near the town of Grantsburg, just east of I-35, and about halfway between Minneapolis and Duluth (about an hour from the Twin Cities). John and I saw hundreds of Sandhill Cranes.  Most foraged in nearby fields, but many concentrated in the marshlands. See my recent blog of 30 October 2011 for more crane information.

Tuesday, November 1, 2011

Rusty Blackbird

Several Rusty Blackbirds at the Sherburne National Wildlife Refuge last Friday were new for my year bird list.  According to Cornell University, the "Rusty Blackbird is one of North America’s most rapidly declining species. The population has plunged an estimated 85-99 percent over the past forty years and scientists are completely puzzled as to what is the cause." Avery (1995), however, indicates that the situation may not be so clear. He writes, "because of its remote breeding habitat, inconspicuous behavior, and lack of economic impact, this species has received little study, and its population status and trends remain poorly known." Rusty Blackbirds breed in the relatively inaccessible far north. Winter birds are often difficult to identify and can be hidden in mixed blackbird flocks, where they are much less common than their flock-mates. The Rusty Blackbird photograph in this post was taken several years ago in South Dakota.