Friday, December 30, 2011

Eastern Screech-Owl

This Eastern Screech-Owl basked in the sun on a very cold winter morning in Aberdeen, South Dakota. The photograph reminds me of Jubba the Hutt in the Star Wars movie. One criticism of George Lucas's science fiction films is that most of his creatures show Earth-like symmetry. Although an eel-like creature lurks here or there, his creatures usually have one head, two arms, and two legs. Because far-away galaxies undoubtedly support different genetic codes and evolutionary histories, their fauna will prove vastly, perhaps unimaginably, different from our own.

Wednesday, December 28, 2011

Great Horned Owl

Although large, Great Horned Owls can be surprisingly cryptic. This owl was on a nest in a relatively small tree, amazingly over a parking lot in the Everglades National Park in Florida. A park ranger pointed the bird out to me, and I showed it to others. I did not expect a nesting owl among the traffic and tourists.

Here in Minnesota, Great Horned Owls are early breeders. They begin to lay eggs by mid-February, with young hatching in April or May. Despite Minnesota's harsh weather, this early nesting allows hatching during peak rodent populations in the spring. I am not always happy to see these owls, as I am told that Great Horned Owls in Minnesota displace Barred Owls.

Sunday, December 25, 2011

White-faced Nunbird

Christmas Day has me thinking about birds named after the heiarchy of the Catholic Church--the first birds to come to mind are cardinals, Red Bishops, and Prothonotary Warblers; monklets and nunlets are out there too--and there are others. This White-faced Nunbird is found in Central and South America. This photo is from Ecuador. Nunbirds eat a variety of prey--insects and other arthropods, and even frogs and lizards, as well as various fruits. They dig nesting tunnels beneath the jungle floor. They are classified as puffbirds, a neotropical bird family. The Handbook of the Birds of the World classifies puffbirds in the order, Galbuliformes (which they share with another tropical family, jacamars), and considers them to be remotely related to woodpeckers, barbets, or motmots.

Wednesday, December 21, 2011

Townsend's Solitaire

On Tuesday, Erika and I read on the MOU listserv that a Townsend's Solitaire was discovered at the Carpenter Nature Center in Washington Co., Minnesota, along the St. Croix River just north of its confluence with the Mississippi. This thrush's range is normally in the mountains of western North America. Often their fall migration only involves moving to lower elevations in the winter. Other individuals may be sedentary. Canadian birds tend to migrate further than more southern ones. Nevertheless, some birds regularly winter across the dakotas and other plains states, where they often prefer cedar trees. Since the 1970s, Townsend's Solitaires have been seen in increasing numbers in Minnesota. The further east you travel, the more infrequent Solitaires become. The normal eastern limit of their wintering range is unclear (Bowen 1997).

Because these solitaires maintain winter territories, they are often relatively easy to see. They often perch high in cedars and give beautiful warbling songs (link with permission of Thayer Birding Software). These two photographs are of the same individual bird. The image below appears much browner than the gray one above, which looks much more typical. This variability, due to the soft December sunlight, is one reason identifying birds from photographs can sometimes be tricky.

Monday, December 19, 2011

Sharp-shinned Hawk

John H. and I censused this hawk during last Saturday's Christmas Bird Count. The hawk's small bill, uniform gray crown, lack of whitish on the nape, and relatively uniform length of tail feathers all point to Sharp-shinned Hawk. The bird tamely sat high in a tree in residential Northfield. As many of you know, the bird count began on Christmas Day 1900 by a group of Audubon Society members who thought they would count, rather than shoot, birds during the holidays. Counts are held across the country (and now the world) and comprise a 15 mile diameter around a central spot. Counts are managed through the Audubon Society and cost $5.00 for participants. More information, including locations of counts near you, can be found at http://birds.audubon.org/about-christmas-bird-count.

Friday, December 16, 2011

Free Advice from 50 years of Birding

I began birding in the fall of 1960. Do I have any advice for young birders? You betcha! Keep a detailed notebook with dates and precise locations of where you find birds. These days you might want to include numbers of individuals seen, in case you one day contribute records to eBird. Don't just include life birds or new birds for the year, but all the birds you see. I suggest a notebook like the
bound sketchbooks available at many art stores. After 50 years, you may be lucky enough to have equally-sized books across your bookshelf.

I do not have good records for those first birds I listed. At the time, checking the species off on the life list in my Peterson field guide seemed sufficient. Beginning in 1961, I have a date and location for each of my over 2,000 life birds. The one exception is from a month in Spain where I recorded the location of my new birds, but not the date. What was I thinking?? In any case, once I saw a bird, I did not record it again. Later I kept year lists, but without dates or locations. I now regret both practices. I wish checklists came with a place to check birds and a space for location.

For the last 20 years, I have kept daily diaries--either in daily calendar books or in those drawing books. These records vary in their usefulness. For example, if one day I drove from South Dakota to Minnesota, I seldom noted the exact location where I saw a particular species. EBird is going to change my laziness! Furthermore, eBird will also automatically update my county lists. Meanwhile, I am entering my old records into eBird (at least those records for which I have data). A final piece of advice--backup your eBird records onto your hard drive. There is no guarantee that eBird will last for the next 50 years!

Now if I can just remember when I photographed this wind-blown, female Northern Cardinal....

Wednesday, December 14, 2011

Western vs. Clark's Grebes

Western Grebes (the top photograph) are locally common in the summer in western Minnesota; Clark's Grebes are also found in the western part of the state, but are rare. (The ratio of the two species in the eastern Dakotas is about 100 Westerns to one Clark's.) I usually see several Western Grebes in Rice County, but, to date, never a Clark's. (These photographs were taken at Sand Lake National Wildlife Refuge in northeastern South Dakota.)

At least four field marks can be used to separate these two grebes. 1) The Clark's Grebe's bill is brighter yellow than the Western's. 2) The Clark's Grebe's eye is surrounded by white, the Western's is surrounded by black. 3) The Clark's Grebes flanks and back tend to be much paler than those of the Western. 4) Clark's Grebes' calls usually have one syllable, while Westerns have two notes. Be forewarned, however, that these grebes are variable in color and plumage, and some can be very difficult to identify. Furthermore, the two species occasionally interbreed, creating intermediate hybrids.

Until recently these two species were considered to be color morphs of a single species. Both grebes perform identical, complex courtship displays. So why are they now thought to be distinct? Western and Clark's Grebes prefer not to breed with each other. In the Dakotas, male Westerns apparently interbreed with Clark's only out of desperation late in the season after they are unable to find an appropriate female. Although DNA sequences are similar in the two species, the differences are of equal magnitude as other closely related species. The difference in the number call call notes is apparently critical in keeping Western and Clark's Grebes reproductively isolated (Storer and Nuechterlein 1992).

Monday, December 12, 2011

Mallard

The Mallard is the most abundant North American Duck. Despite being heavily hunted, Mallard populations remain relatively constant. This species' success "reflects its adaptability to varied habitats, its hardiness in cold climates, its catholic food tastes, and its tolerance of human activities" (Drilling et al. 2002). John H. and I found a large Mallard flock basking in the sun in a parking lot near Hastings, Minnesota.  Although the day was cold (below 20 degrees F), and a nearby pond was frozen over, open water flowed in the vicinity.

Saturday, December 10, 2011

American Tree Sparrow

Birding the other day in the snow and cold near Circle Lake in Rice County, I came upon a flock of about a dozen American Tree Sparrows. Having seen little else during the trip, I wondered how this hardy winter visitor survives the cold. Typically individual songbirds can withstand colder weather in the winter than they can in the summer. A zero degree day in July will kill them. Small birds can also increase their metabolic rates by breaking down internal organ weight. By these and other behaviors, our small winter residents are not usually challenged by Minnesota winters. 

Thursday, December 8, 2011

Gray-winged Trumpeter

In 1976, I took this Gray-winged Trumpeter photograph deep in the Ecuadorian jungle, south of the Napo River. I was doing bird surveys for a proposed national park. We were in an unnamed village of Waorani, an only recently contacted tribe. These people kept pet trumpeters as snake alarms. When Gray-winged Trumpeters discover snakes, the birds make a loud, distinctive, crane-like call given only in the presence of snakes. Other trumpeters join in the ruckus. Trumpeters will eat small snakes, but just alert the village to the presence of larger ones.

Trumpeters have proven almost impossible to breed in zoos. Even the Waorani raise their pets from wild-collected eggs. The young birds imprint on their human foster-parents and will call loudly when strangers approach, thus acting like a watch-dog. Most ornithologists agree that these ancient, grouse-like birds are not grouse or quail, but closely related to cranes and Limpkins (Handbook of Birds of the World, Vol. 3).

Wednesday, December 7, 2011

Bobolink

Most birds exhibit countershading. They are dark above and pale below. This pattern flattens their profiles and shades their pale underparts. The color of their surroundings may also reflect on the underparts, further camouflaging the birds. Predators find countershaded birds to be very hard to see. Then why do male Bobolinks show reverse countershading? Most likely this reversal makes Bobolinks highly visible to females in their grassland habitat. The advantages of being extremely visible to potential mates must outweigh the dangers of predators. Additionally, predators may follow males and miss seeing breeding females.

Monday, December 5, 2011

Northern vs. Loggerhead Shrike

Northern and Loggerhead Shrikes can be difficult for beginners to identify. Kim Eckert, in his A Birder's Guide to Minnesota, wisely writes, "a shrike in Minnesota May through September is 'always' a Loggerhead; a shrike November through February almost always a Northern." (Kim's guide is an excellent source for learning how to identify birds.) In this post, the first two photographs are first-year Northern Shrikes, the last, taken in Florida, is an adult Loggerhead.
One problem is that one really needs to be familiar with both species to easily identify them. Beginners are often misled by field guides that suggest that identification is easy, and, consequently, Northern Shrikes are sometimes misidentified as Loggerheads in the winter. Northern Shrikes are bigger than Loggerheads. Northerns have larger, more strongly hooked bills. Some of the less reliable marks mentioned in books include the Northern's narrower black mask that usually does not continue in front of their eye (or continue above the bill), and the Northern's more strongly barred underparts. Both these field marks can be difficult to see in the field. Note, for example, the Northern Shrike in the second photo in this post.
Northern Shrikes are uncommon but widespread winter visitors to Minnesota. Loggerheads are rare and local in the summer. Loggerhead Shrike populations across North America have seriously declined in recent decades. The reasons for this trend are unclear, but probably include widespread spraying of biocides, clearing farm trees and shrubs, and an unfortunate tendency to be hit by automobiles. Predation by house cats, competition with kestrels, and historic persecution by people add to the Loggerhead Shrike's woes (Yosef 1996).

Saturday, December 3, 2011

Blue-winged Teal

The Blue-winged Teal photograph above is one of my favorite photographs taken several years ago from a blind in Pierre, South Dakota. The teal below are from Rice County this spring (27 April 2011) when I was trying to photograph duck pairs. Blue-wing Teal are early migrants to Minnesota. They form pairs in the late winter or during spring migration. Nest failure can be over 90%--mostly due to mammalian predators. Blue-winged Teal numbers, however, depend on prairie wetland conditions. In dry years, populations fall. In wet years numbers can double (Rohwer et al. 2002).

Thursday, December 1, 2011

Gadwall

These two photos, both taken on Cannon Lake near Faribault, Minnesota (27 July 2008 above and 17 March 2009 below) just about cover Gadwall identification. In all plumages, their white wing patches are usually diagnostic--if you can see them. The gray-sided males show black under tail coverts. Erika calls them "Black-assed Ducks." In the first photos, the female, looking a lot like a small female Mallard, might be hard to identify. (Indeed, the duck in the upper left of the lower photo is a Mallard.)

Gadwalls are monogamous. Pairs form as early as November on their wintering grounds in the southern United States and the Mexican coast. Nesting in dense vegetation and often on islands, Gadwalls enjoy high reproductive success. As with many other ducks, pairs break up during incubation, when males join molting flocks. After incubation, the females rear their young in larger lakes. The young are independent ten weeks after hatching (Leschack et. al 1997).

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.

Sunday, October 30, 2011

Sandhill Crane

On Friday, Erika and I finally made the drive to Sherburne National Wildlife Refuge, about 90 miles from Northfield and just beyond the northwest suburbs of greater Minneapolis. Comprising over 30,000 acres of wetlands, oak savannas, and prairies, the refuge lies in the transition zones between eastern woodlands and prairie as well as northern and more southern forests. This wilderness, relatively close to the city, amazed us. The lakes and marshes almost reminded me of parts of Florida! One reason to visit Sherburne in October is the refuge serves as a staging area for migrating Sandhill Cranes. On Friday, refuge personnel counted 5352 Sandhill Cranes, and we had no trouble finding them in harvested fields northeast of the refuge. I was surprised how close they allowed us to approach (although we did not leave our car, which we used as a mobile bird blind).
Sandhill Cranes are awesome. Genetic studies suggest that these cranes are an old species without close relatives. They are more closely related to Australian cranes than they are to the Common Crane of Europe. Sandhill Cranes live to over 20 years, do not breed until they are 2-7 years old, remain in stable pairs over at least several years, and provide extended care to their young, staying together for almost a year. They usually only fledge one young per year.
Sandhill Cranes migrate and winter in large flocks. The use of migratory staging areas makes them particularly vulnerable to loss of wetlands. In Sherburne, the cranes roost in marshlands and feed in the surrounding fields during the day. As they fed, we saw several cranes dance. In the fall, these dances are antagonistic displays, protecting feeding space or family groups. As you might predict, antagonistic displays are most often done by males.
Family groups remain together from hatching through the following March. The advantages of family groups for the young include more feeding time, fewer aggressive encounters, and less time spent watching for predators. Juveniles outside of family groups tend to be in poor physiological condition.
Minnesota Sandhill Cranes migrate through the eastern and central United States and winter in Georgia, central Florida, the Gulf Coast and Texas. These cranes, along with others from Canadian breeding grounds, stop at staging areas during migration. Huge crane concentrations form in the spring for up to six weeks in the North Platte and Platte river valleys in Nebraska.
Cranes begin their migratory flights in the morning and usually stop near sunset. They cover about 250 km per day at speeds up to 83 km/hour (depending on wind conditions). They fly at altitudes of up to 2500 m. They prefer sunny days with tail winds. They are often inspired to migrate by seeing crane flocks overhead.
My source for almost all of this crane information is Tacha et al. (1992, The Birds of North America Online).