Tuesday, November 30, 2010

Southern Cassowary

Although my vote for favorite bird during our 1990 Australian expedition is the Tawny Frogmouth (see last post), my family picks the Southern Cassowary. Cassowarys mainly eat fruit. Indeed, they are ecologically important. Fruit seeds are dispersed as they pass through cassowary digestive systems.  The birds also consume a wide variety of other vegetable and animal prey.  Although usually shy, they can be dangerous when defending their nests or young.  Notice the young cassowary to the right of the adult. The function of the horn is unknown--perhaps a sexual ornament or maybe a defensive armament.

We found this cassowary in the rainforest near Mission Beach, Queensland.  We asked our motel clerk where to find them.  He replied, "The Chamber of Commerce won't approve of what I am about to tell you.  The best place to find them is in the town dump."  That's where we took this photograph.  Discovering the Cassowary was like finding a living dinosaur strolling among the rusting cars and rotting garbage. 

Monday, November 29, 2010

Tawny Frogmouth

As we flew to Australia in 1990, an Aussie on the never-ending plane trip told us not to miss the Koala Park in Melbourne.  "Your kids will love it."  He was right.  On the way out of the parking lot, Erika exclaimed, "I think you'd better stop the car--there is a cool bird perched on a pine bough over the road!"  There sat a Tawny Frogmouth, my favorite bird of our trip.  (The rest of the family's vote will appear in my next post.)

Frogmouths are in the family Podargidae  They are in the same order as nightjars. They are not closely related to owls. Frogmouths are found in southeast Asia and Australia.  The Tawny Frogmouth is a nocturnal omnivore--it eats most anything, including mice, birds, and lizards--although mainly arthropods.  Frogmouths usually drop from their perches and capture their prey on the ground. They accomplish their capture with their bills, not their talons.  Occasionally they will sit motionless, snapping up passing insects (Nightjars, Potoos, Grogmouths, Oilbird and Owlet-nightjars of the World).  Although this frogmouth is locally common to abundant, we saw no others.

Saturday, November 27, 2010

Kea

In 1990, Erika and I presented our antbird parasite research at the International Ornithological Congress in Christchurch, New Zealand.  One of the advantages to working at a small college--Northern State University allowed us to teach our classes an extra half-hour during the semester and we gave our final exams at Thanksgiving.  We packed up our family and spent a week in New Zealand and over a month driving up Australia's east coast.  Needless to say, we enjoyed numerous adventures.

On our last day in New Zealand, we rented a car rather than pay for one of the congress's excursions. (We should have struck out on our own from the beginning!)  Despite driving on the left side of the road, we found ourselves at Authur's Pass, high in the New Zealand Alps.  Our goal was the Kea,  the world's only alpine parrot and restricted to New Zealand's South Island.

We arrived at the pass at noon. A park official informed us, "Your timing is rotten, mate.  Keas are only seen at dawn and dusk."  Crestfallen, we continued a short distance away from the pass and parked at a roadside rest.  Suddenly a Kea flew over and landed on a nearby rock.  I inched my way toward the bird, taking photos as I approached.  A bus full of Japanese tourists stopped and they began taking photos of the birder getting closer and closer to the large parrot (I am not sure they were that interested in the bird). The photo below is uncropped.  I am not sure I wanted to get any closer to that beak!
Keas are omnivorous--they will eat almost anything, animal or vegetable.  Unfortunately that includes sheep, an animal you do not want to poach in New Zealand.  The government paid a bounty on Keas until 1970.  By then, only about 5000 Keas remained.  Full protection was afforded to the Kea in 1986.  Since 1999, Kea numbers have again fallen, presumably due to nest predation by possums.  Today the bird is considered to be endangered (Wikipedia).

Keas have an odd predilection for rubber.  The bird I was photographing flew up, and was joined by a second bird.  Both landed on our rental car and began tearing at the window sealant--much to our younger son's consternation. He had remained in the car, being once again embarrassed by his father's bird chasing.  Keas are known to slash car and bike tires and make moon-roofs out convertible tops. Keas will also carry off any belonging left unguarded.  When we returned our car to the rental company, we did not mention the Kea attack.

Thursday, November 25, 2010

Bird Art


Last May I blogged, "When I see Rose-breasted Grosbeaks, I am reminded of my favorite artist, Louis Agassiz Fuertes." One of his sketches of grosbeaks is just stunning.

One of my photographs from Florida last January also reminds me of Fuertes.  In this case, the long plumes on the head and neck on a Tricolored Heron reminds Fuertes' 1929 portrait of feathers on an Egyptian Vulture.  You may recall that I wrote that Fuertes was killed at a railroad crossing in 1927.  There are times when we birders should keep our attention away from birds! A biography and a collection of his paintings is to be found in A Celebration of Birds and in the following link to  Cornell University.

I think my favorite living bird artist is Lars Jonsson, whose work crosses that line between superb illustration and great art. He has published a collection of recently completed work. This book also discusses his technique. The book is worth perusing if you are interested in bird art.

Tuesday, November 23, 2010

Snow Bunting

Today I saw hundreds of Snow Buntings in several flocks near Nerstrand Big Woods State Park in Rice County, Minnesota.  Between the busy state highway and relatively uncooperative birds--not to mention the 18 degree F temperature--I did not get very good photographs.  In fact, the photo above of a Snow Bunting that I took several years ago.  Today's photos were more like the one below.
Snow Buntings breed in Alaska and across Arctic Canada where they nest in rock cavities. They winter from southern Canada to the central United States.  Although they can be of sporadic occurrence, and numbers vary from year to year, these buntings can be locally abundant, and are often seen along Minnesota highways.

Sunday, November 21, 2010

Winter Reading

One of the books that inspired me to become a birder was Wild America by James Fisher and Roger Tory Peterson.  The book recounts the authors' 1953 road-trip across North America and northern Mexico.  At the time, their list was the record for birds seen in one year in North America.


I am currently reading Scott Weidensaul's Return to Wild America. This book gives the reader a history of American conservation challenges over the past half-century. The author retraces Fischer and Peterson's route and discusses fifty years of environmental change and growing public support for environmental causes.  Despite urban sprawl, not everything has gone downhill since the 1950s.  Since then, many of the hallmark environmental laws have been passed and many acres have been preserved for wildlife. The result is that bird populations have changed, often for the worse, but occasionally for the better.  A small drawback is that Fisher, Peteron, and Weidensaul all avoided the upper Midwest.

I picked up Return to Wild Ameica because I enjoyed Weidensaul's Of a Feather, a well-written and entertaining history of North American birding.  I can recommend this book to anyone wishing to learn about the history of ornithology and birding in the United States.

Thursday, November 18, 2010

American Crow

 
American Crows are abundant across North America.  Picking what to write about crows is difficult. They are intelligent.  They employ a number of information-laden calls, they recognize individual people (although few people can recognize individual crows), and, generally speaking, crows are less wary in cities than in the countryside. I encountered these crows as they foraged in a Northfield field (the day before the snow arrived).

For the past several years, we enjoyed a huge winter crow roost in our backyard.  The birds reminded us of the flying monkeys in the Wizard of Oz.  I do not know why the roost was abandoned this year.  Crows seem to be exceptionally prone to West Nile Virus.  This Old World disease appeared in New England and spread across the country.  I once wrote a paper demonstrating that banding returns show that crow populations are are not isolated, but potentially can come in contact with infected birds across the continent.

Young crows help their parents raise subsequent broods, sometimes for two or three years.  Not all young are helpers, and we do not know why some young help while others raise their own offspring.  Do the baby-sitting helpers eventually become better parents? Do parents pass genes to some offspring that effectively enslave some young, thereby increasing the parents' reproductive success compared to crow families without helpers?

Tuesday, November 16, 2010

Muskrat

I encountered three muskrats on one of our last, warm November afternoons.  Muskrats feed mainly on aquatic vegetation.  They are not dormant during the winter, and must eat every day. Muskrats, rats and mice belong to the same family.  Muskrats owe their name to their musky scent glands with which they mark their territories.

Muskrat populations expand and contract through a 6 to 10 year cycle. The muskrats in this photo are likely a family group. They burrow in bank-sides of lakes or streams or they build lodges with underwater entrances.  Muskrats also build platforms for feeding.

Sunday, November 14, 2010

Sharp-shinned Hawk

Because this forest-inhabiting hawk subsists almost entirely on small birds, this Sharp-shinned Hawk was probably attracted by the activity at our feeders.  I banded it on 8 November.  The hawk flew up from our water feature, where it may have been drinking.  At the time, no small birds were evident.

Male Sharp-shinned Hawks are much smaller than the females.  The size of the sexes do not even overlap.  This bird, with a wing chord of 203 mm, is a female.  Her yellow eye and brown back indicate she is a young bird.

Several hypotheses exist to account for female hawks being larger than their mates. Perhaps females need to be larger to protect themselves from dangerous, aggressive males. Alternatively, perhaps to reduce competition between the sexes, males and females specialize in different sized prey. Apparently, for whatever reason, the more a raptor specializes in taking small birds, you expect to see a larger difference between the size of the sexes.

Friday, November 12, 2010

Cackling Goose

While taking photographs of Canada Geese (see first photo) in the Cannon River within the city of Northfield, I noticed that about a quarter of the flock were smaller and tended to stay away from the larger geese.  The smaller birds' bills are relatively shorter and stubbier, giving the bills a triangular appearance (see middle photo).   Additional field marks add up to the small birds being Cackling Geese. 
1. In the photo at the end of this post, a Cackling Goose swims in front of two Canada Geese.  The head is not as round as in the middle photo above, but not as wide as in the Canada Goose.  (The Cackling Goose in the bottom photo shows kind of a squarish, rather than round, head--but that is OK.)

2. The forehead of the Canada usually has more of a slope to it than does the more angled Cackling forehead.

3. The Cackling Goose tends to have a relatively shorter neck--a field mark that is apparent in the lower photo, but murky if the bird is stretching its neck out as in the middle photo.

4. Cackling Geese show slightly darker breasts than do Canadas, a mark that can be seen in the photo below. 
Until recently, Cackling Geese were considered to be a small race of the Canada Goose.  Genetic studies indicate that the two forms are distinct species.  Paul Hertzel, Ross Silcock and Stephen Dinsmore have published a website that further discusses identification issues with these geese. They warn that not every Cackling Goose, especially when solitary, is easily identified.

Wednesday, November 10, 2010

Tundra Swan 2


Do any field guides depict ducks dappling?  For today's quiz, name these ducks!   The swan is not difficult.  Its meter-long neck allows the Tundra Swan to feed in relatively deep water on plant stems and roots.  Often the feet are used to dig up plants. This swan also feeds in agricultural fields in the winter and arctic meadows in the summer (Limpert and Earnst 1994).

Moments after I took the photograph above, all three waterfowl came up for a breath--and I took the next photo.  You can see the answers to the quiz--Tundra Swan, Mallard, and Northern Pintail.  This post is the last from our trip to Brownsville, Minnesota. For finding birding spots in Minnesota, Kim Eckert's A Birder's Guide to Minnesota is indispensable.

Tuesday, November 9, 2010

Bald Eagle 3

Most of the eagles we saw on Friday were not in adult plumage (you may recall that Bald Eagles take four years to attain their black and white plumage).  Bald Eagles are sometimes confused with Golden Eagles.  But Bald Eagles have arrow dark bands at the ends of their tails and lack distinct white patches on their upper wings. All the eagle photos on this post are of Bald Eagles.
The eagles appeared to play.  Individuals swooped and tumbled with each other. This sort of behavior prepares them with survival skills. A couple of young eagles made passes over a flock of Common Goldeneyes.  Bald Eagles, when they are not scavenging dead prey, often hunt by soaring.  Their soaring capture rates are low.  We wondered if our birds were just testing the goldeneyes to see if any one of the flock was wounded.

Monday, November 8, 2010

Bald Eagle 2

Dozens of Bald Eagles were almost as exciting as Tundra Swans during our Friday road-trip.  The Bald Eagle's recovery is one of our premier environmental management successes.  Their populations plummeted due to persecution (Alaska offered a bounty on Bald Eagles) and lowered reproduction from DDT contamination.  This species' rebound is such that by the late 1990s, Bald Eagles now breed across Canada and in all the contiguous states except Rhode Island and Vermont (Buehler 2000).
Bald Eagles are monogamous and thought to mate for life unless a mate dies. Pairs apparently stay together throughout the year. One problem with studying Bald Eagles, however, is that banding adults is difficult.

Sunday, November 7, 2010

Tundra Swan 1

On Friday Erika and I took a road-trip to extreme southeastern Minnesota, just south of Brownsville.  We hoped to see flocks of Tundra Swans.  We had no trouble finding the swans.  Just south of Brownsville, the Fish and Wildlife Service has built two overlooks just where the swans are most easily seen.  We saw hundreds.
Tundra Swans breed in arctic Canada and Alaska and winter either in the Pacific Northwest or in the Chesapeake Bay region.  Swans heading towards the bay fly across much of the northern Great Plains.  These birds rest up and refuel near Devil's Lake in North Dakota and in the upper Mississippi Valley in southeastern Minnesota.  They leave the arctic in late September and arrive in Minnesota in early October.  They leave here and make a non-stop migration to the Chesapeake (1600 km), arriving on the East Coast from mid-November through December.  (Western Swans rest in Utah, before proceeding to California and Oregon.)
Tundra Swans migrate in family groups within flocks that can be over 100 birds. Before mating at 2 or 3 years, young swans may "date" other swans.  Once mated they are monogamous and remain together all year.  Divorce is rare, although presumably they will remate if one of the pair dies. (Much of this information is from Limpert and Earnst 1994).

Saturday, November 6, 2010

Pileated Woodpecker

Some readers my recall my 5 November 2009 entry in which I posted a gif of a Pileated Woodpecker giving me a hard time. My hands were also bloodied after banding this first-year male bird.  I was glad, however, to add this species to my series of white-background photographs.  I use white mat board as background when I take the pictures (although I was first inspired by taking photos of birds in front of snow drifts last winter).

Pileated Woodpeckers depend on large trees for breeding.  This dependancy becomes critical if large trees are cut out of forest stands.  Pileateds breeding in our backyard had their tree fall in the 2009 winter during a windstorm.  The birds must still be in the vicinity, since this Pileated in the second bird-of-the-year I have banded in 2010. Large trees also attract lightening (especially when surrounding trees are smaller), sometimes to the woodpeckers' detriment. Large trees come at such a premium, that pairs defend their territory all year.  Individuals do not abandon territories if their mates die.  Pileateds are also often hit by cars, since the woodpeckers often feed on or near the ground.  Despite these dangers, Pileated Woodpecker populations appear to be increasing since the mid-1960s (Bull and Jackson 1995).

Wednesday, November 3, 2010

Hooded Merganser

Hooded Mergansers are among our most handsome ducks.  For the past few falls, I have been aware of a small flock inhabiting a lake next to Spring Creek Road in Parmeadow Park near one of Northfield's golf courses.  With high traffic, both pedestrian and automobile, these birds are relatively tame.
Other mergansers survive almost entirely on fish.  Hooded Mergansers capture more diverse fare, including fish, insects, and crayfish.  Although acid rain is a threat to many breeding populations, Hooded Merganser populations are healthy (Dugger et al. 2009).
I have previously witnessed this behavior in other male Hooded Mergansers.  The birds rear and flap their wings after surfacing from dives.  They may be drying themselves or, perhaps, signalling their location to other surfacing flock members.

Monday, November 1, 2010

Bald Eagle


On Friday, Erika and I birded locally.  We flushed this Bald Eagle as we drove around a corner on the north edge of the Carleton College Arboretum along Little Canada Road.  The eagle briefly perched atop a nearby pine, but then flew away. 

"That would have made a good blog entry," remarked Erika.  "Not without a photograph." I replied.  About 20 minutes later, we returned to the same spot.  We found the eagle perched in a large oak and I was able to take one photograph before the bird again flew. 

Bald Eagles require four years to obtain their striking adult plumage. During these years, the eagles continually molt, and so continually change their appearance. According to the description is the Peterson Field Guide Series, Hawks, our bird is probably a second-year bird. This book is a decent field guide to birds of prey and can be obtained through the accompanying link at bargain prices. (Two volumes by Brian Wheeler may be better, Raptors of Western and Eastern North America, but they are expensive.  Minnesota is covered in the Western volume.)
The eagle was feeding on an opossum carcass. I assume the opossum was road-kill and that the eagle was scavenging. A cursory search of the literature finds no mention of Bald Eagles consuming opossums.  Eagles are primarily fish-eaters, but are known to take a wide variety of prey when fish are not available.  Arthur C. Bent, in his monumental masterpiece Life Histories of North American Birds of Prey, wrote, "As eagles do not disdain carrion, they may often be seen...feeding on the carcasses of any animals they can find.." This 26-volume set of books is now somewhat dated, but still contains a wealth of information.  The books were first published by the Smithsonian and then reissued as Dover reprints. Prices for these books vary greatly, so some research is advised if you are interested in obtaining them.

If you are interested in up-to-date life histories of birds, the American Ornithologists' Union's Birds of North America is now a continually evolving, on-line resource.  Subscriptions to the series are pricey, but free to AOU members!  Some libraries have copies of the print version of Birds of North America, but they do not appear to be available through Amazon.