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.

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.

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).

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).

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.

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.

American Robin

I banded this scruffy juvenile American Robin on 10 October.  Most robins have completed their prebasic molt by October.  This bird was either a late hatchling or perhaps had some sort of physiological block to molting into adult plumage. In any event, the spotted juvenile breast spotting clearly allies robins to most other thrushes. (I last blogged about Robins on 13 July 2010.)

Despite banding no robins in June and July, October has been a banner robin month.  The robins are attracted to our water feature. This month I banded 132 robins at my Northfield residence.  For the past week, our little cul-de-sac has been blanketed by hundreds of robins. I previously reported the super low pressure cell that roared across Minnesota with rain and 60 mph wind gusts.  I banded 40 robins in the two days before the storm (24-25 October) and 25 more on the morning of 28 October.  During the two-day storm, the robins remained abundant (but I was marooned indoors). The sun returned the afternoon of the 28th, and many of the robins have departed--on the 29th I banded only 11.

Roxie Laybourne

The highlight of my high school career was being taken under wing by Roxie Laybourne. Every Thursday night, Roxie held court in the bowels of the Smithsonian as she held bird-skinning sessions. I prepared many bird specimens, including an embryonic Whooping Crane, a casualty of the Federal crane recovery program.

Later, after a long day visiting the capitol and the Washington Monument, I introduced Erika to Roxie at a skinning session. Erika declined Roxie’s invitation to skin a bird. Roxie took me aside and said, “This isn’t the girl for you.” But years later apologized and said she had been mistaken; perhaps after visiting us in Ecuador and seeing Erika sew the head back on a poor shot up Pygmy Tyrannulet—a flycatcher no bigger than a thumb. The photo above shows Roxie and Erika, when Roxie visited us in the Ecuadorian jungle.

During one of my college jobs, I did a stint with Roxie at the National Museum. I banded my first birds that semester in the woods near Washington. My first bird was an Ovenbird, banded near a drug deal being consummated nearby. Banding at Roxie’s was much preferable! One of my banded birds, a Red-bellied Woodpecker, became the oldest on record, at 13 years.

When they were young, my sons realized that Roxie was famous when she was interviewed by Big Bird on Sesame Street. Late in her career, Roxie realized that birds could be identified by microscopic examination of single feathers.  She became a forensic specialist for the FBI and also studied bird strikes by aircraft. Most importantly, she inspired a host of young people who later became ornithologists.

Ancient Murrelet

With 55 mph gusts and possibly the lowest air pressure in Minnesota history expected over the next two days, the first and only record of an Ancient Murrelet in South Dakota comes to mind.  A farmer in Ipswich, in the north-central South Dakota, found the bird in November 1993 after a snow storm. Ancient Murrelets feed off the Pacific shore of North America. They breed in burrows along the coasts of British Columbia and Alaska; they winter further south to the California coast.  The storm that brought this murrelet originated in the North Pacific was exceptionally large. 

The bird died soon after being found.  The body was given to Dave Williams, who, in turn, gave it to me.  I prepared the carcass as a museum specimen, and sent to the U.S. National Museum.  I have never encountered a more emaciated bird. Williams wrote up an account of this discovery in South Dakota Bird Notes (46:34) and mentions that six records of this species exist for Minnesota (and at least two of the somewhat similar Dovekie).

South Dakota birders had been on the lookout for an auk, the family to which murrelets belong.  Laura Ingalls Wilder, in her autobiographical classic, The Long Winter, reported her father's finding a strange bird after an October 1880 blizzard.  After the storm, they released the bird, which they tentatively identified as a Great Auk (but which, based on her description, was probably a murrelet or a Dovekie) (Steve Van Sickle (1988) South Dakota Bird Notes (40:95-96)).

John Trott

John Trott was my seventh grade teacher. I joke that, in his class, you didn’t have to learn math or English, but you did have to learn to identify birds. John banded birds and his students could help, if they passed a written exam. The exam was a page long, but all answers had to be spelled correctly.

“What does AOU stand for?”

“American Ornithologist’s Onion.”

It took me three tries to pass. John once commented that he thought people don’t change after the seventh grade. He may be right—I still can’t spell.

I am surprised how little of an Internet presence John has. He died in September 2000. I came to his class in 1960. I know this date because I have bird lists back until then. I was 14.

John was like no teacher I had ever had before. John was temperamental, unpredictable, gossipy, and an opera lover. Aside from learning about birds, we also made an extensive plant collection. Although I was not aware of it, this learning was hands-on and peer-mentored. John also read to us. He asked my parents’ permission for me to read an x-rated book, “The Big Sky,” about trappers in frontier South Dakota. Little did I know that I would grow up to teach in that state for almost 30 years. The point here is that John treated us seventh-graders as adults.