Monday, February 29, 2016

Trumpeter Swan

Erika and I counted 21 Trumpeter Swans on 27 February. We hiked along the edge of the Minnesota River at the Bass Ponds at the Minnesota Valley National Wildlife Refuge. Trumpeter Swans were once common and widespread. Over-harvested by the feather trade, by 1935 only 69 birds remained. Reintroduction and strict management saved Trumpeter Swans. In 2000, about 2300 birds were censused; by 2010 the population is thought to be over 46,000 (Wikipedia). Now there are over 2400 wild Trumpeter Swans in Minnesota alone (MN DNR). The DNR notes that the main threats to swans include ingestion of lead shot, habitat destruction, collisions with power-lines, and illegal shooting.

Adults are the largest of the North American waterfowl. They are usually all-white. Sometimes their heads and necks sport a golden-brown stain, obtained from the iron-rich water and mud in which they often forage (Mitchell and Eichholz 2010).

Saturday, February 27, 2016

Mourning Dove

This Mourning Dove posed for me last summer at the Carleton College arboretum. Mourning Doves are abundant and widespread across North America. Eastern birds are larger and darker than western ones, and the two populations are distinct subspecies. 

These doves owe their suceess to being habitat generalists. They are found both in farm country and in cities. The total population in the United States is estimated at 350 million. The Mourning Dove is our most popular gamebird, with hunters taking over 20 million birds every year. Mourning Doves live only about a year, even without hunting pressure, but they can bring off nestlings every 30 days. Where weather prermits, they can breed all year (Otis et al. 2008).

Thursday, February 25, 2016

Black Duck

John Holden and I enjoyed a fruitless expedition to Presscott, Wisconsin. We saw very few birds. On the way home, we stopped at Lake Rebecca Park near Hastings, Minnesota. Along with 150 Mallards, swam three ducks that were clearly much darker than the others. You can see two of these ducks in the first photo—American Black Ducks. Their finely streaked throats and relatively unmarked, greenish-yellow bills confirmed our identification. The American Black Ducks isolated themselves from most of the Mallards.

“Hybridization of an abundant species with a less abundant and declining one can lead to genetic extinction of the species with the smaller population” write Longcore et al. (2000). When I was young, that scenario was playing out for the American Black Duck.  Mallards were becoming abundant and hybridized with Black Ducks. The Black Ducks were over-hunted as their northeastern North American breeding range was degraded. But, thanks to the Black Duck’s wide range and to stringent hunting regulations, this species appears to be on the rebound. 

Tuesday, February 23, 2016

American Goldfinch

On 18 February 2016, I banded this American Goldfinch. Because of its jet-black wing feathers, I knew it to be a male. The shoulders were not bright yellow, so I knew this was a second-year bird. Males in basic (winter) plumage tend to have variable amounts of black in their crowns. Males with more black in the crown tend to have brighter yellow bodies. McGraw and Middleton (2009) suggest that the possibility exists "of a non-breeding-season function to these ‘remnant’ colors.” Since my goldfinch is a second-year bird, its black crown feathers are probably not remnants from a previous summer, but recently molted—a sign of spring!

Sunday, February 21, 2016

Common Redpoll


On 18 February 2016, I banded my first Rice County Common Redpoll of the year. Annual redpoll numbers fluctuate greatly. When spruce and birch seed production fails in the arctic, redpolls head south. Mid-February seems like a late winter arrival date for wandering redpolls. Birds have little fidelity to specific breeding sites and tend to be nomadic in their winter wandering. A redpoll banded in Michigan was recovered in eastern Siberia. Another, banded in Belgium, was recovered two winters later in China (Knox and Lowther 2000). On the other hand, despite having ringed thousands of redpolls, none of my birds have been recovered.

Friday, February 19, 2016

Black Gray Squirrel

Last week John Holden and I photographed two black squirrels in Denison, Goodhue County, Minnesota. Both Fox and Eastern Gray Squirrels have black morphs. Since these squirrels were the same size as nearby, Gray Squirrels, I believe these may be Gray Squirrels.

Originally Gray Squirrels were black in Canada and in other northern parts of their range. Fox Squirrels have a similar range, but they are more often black in the southern United States. In much of their range, especially in western regions, black squirrels are most common where either Fox or Gray squirrels have been introduced. Apparently black squirrels were often introduced because they seemed more exotic than “normal” squirrels.  Nature.com gives two examples. Black Squirrels in Kent, Ohio, were introduced from Canada in the 1950s. Marysville, Kansas, black squirrels escaped from a carnival in the 1920s.

Wednesday, February 17, 2016

Australian King-Parrot

Working through a few unposted photos, I came upon this Australian King-Parrot. On 16 December 1990, our family visited the Blue Mountains National Park in the mountains west of Sydney. This parrot is common in forested areas of eastern Australia. 

Adults tend to be sedentary. Flocks of young birds wander in search of corn and fruiting trees. They are also fond of eucalyptus, and a wide variety of native and introduced plants, taking both seeds and nectar and flowers. In the non-breeding season, they also raid farms and visit parklands (Collar 2015).

Sunday, February 14, 2016

Red-winged Blackbird

On June 29, 2015 along the Layman Lakes on the Carleton College campus, I was scolded by this female Red-winged Blackbird. Nearby perched a fledgling—a young bird only a mother could love! Young songbirds are “blind, largely naked, and poorly coordinated at hatching.” In hatchlings, the eyes do not open until after their first week. By ten days, they increase their weight ten-fold, and grow to over half the adult size (Yasukawa and Searcy 1995). This baby was able to fly, but had difficulty nailing its landings.
DNA studies indicate that Red-winged Blackbirds are not very faithful mates. Males and females often copulate with birds outside the pair bond. Fledglings from the same nest are often step-siblings. Red-winged Blackbirds are among the most common of North American birds. They often damage crops and human efforts to control these blackbirds are a major source of mortality.

Friday, February 12, 2016

Brown Creeper

On Thursday, I watched a Downy Woodpecker perched stock still at the suet feeder. Erika exclaimed, “there is a Brown Creeper doing the same thing!” I assume both species behaved this way in response to a Sharp-shinned Hawk that patrols the back woodlot. Poulin et al. (2013) confirm this behavior in creepers: “adults became silent and “froze” with bodies pressed tight against bark in response to presence...or call of Sharp-shinned Hawk.”

These authors also report that no information is known about Brown Creeper parasites. If you look closely at this photograph (perhaps by enlarging it on your computer screen), you may notice a tick or possibly a feather mite. This parasite is embedded in the bird’s head between the bill and the eye.

Thursday, February 11, 2016

Mute Swan

Mute Swans are an Eurasian species introduced to North America. The swans were released in city parks, estates, and zoos.  They are increasing in numbers the wild along the Atlantic coast, the Great Lakes region, and the Pacific Northwest. I have seen them in New England, a few in Minnesota, and a couple of times in South Dakota. This photo was taken in New York at the Storm King Art Center on 11 September 2009.

The problems with Mute Swans include their overgrazing aquatic vegetation and their displacing native waterfowl. Breeding pairs can be fiercely territorial, often attacking people and pets. Programs, including capture or culling, now help control this invasive species (Ciaranca et al. 1997).

Monday, February 8, 2016

Dark-eyed Junco

On Friday Erika and I made a brief visit to the University of Minnesota Landscape Arboretum. I was happy to see a small flock of Dark-eyed Juncos. Although a few winter here in Minnesota, most travel further south from their transcontinental breeding range across Alaska, Canada, and some northern and mountain states.

Elsewhere in this blog I wrote about the “turbulent taxonomic history” that has been a “nightmare” for ornithologists. At one time, five species of junco were recognized. These days, there are only two species with at least 15 races (Nolan et al. 2002).

This junco’s brown back that contrasts with the gray head gave me pause. What is this junco?  A western Oregon Dark-eyed Junco?  Or an intermediate “cistomontanus,” a race that has been variously assigned to western Oregon and eastern Slate-colored Juncos?

This bird is probably a first-winter Slate-colored Junco. Its flanks are gray. Females can be quite variable, and may sport brownish backs and/or buffy flanks. The authors cited above write, "many records in East probably pertain to brownish variants of J. h. hyemalis (which are also often confused with oreganus group in the East)."

Saturday, February 6, 2016

Marsh Wren

During John Holden and my visit to nearby Sprague Lake on 20 May 2015, we kicked up this Marsh Wren. Their rich but limited marsh habitat affects these wrens in a number of interesting ways.

You can see that they are adept at making their way through the marsh. They would be hard to find, except that they are almost continually singing. Males learn up to 200 song types, with which they have verbal duels with neighboring competitors. Females may also be attracted to males with rich repetoirs.

Females are attracted to males with rich territories. In some marshes, half the males mate simultaneously with two or more females. Males are so “zealous” that them build multiple nests, some times six dummy nests for every nest used by a female.

This extraordinary competition also leads Marsh Wrens to destroy competitors’ and other species’ eggs. Box sexes of Marsh Wrens destroy eggs that they find. Information and the quote in this post comes from  Kroodsma and Verner 2014.

Wednesday, February 3, 2016

Dancing Dragonflies and Damselflies

I am pleased with the recently published third edition of my book, Dancing Dragonflies and Damselflies. The book is 208 pages, with color photos of about 90 species of odonates, most from Minnesota, but others from our various travels. Since the book is published on an per-order basis, the traditional formats are ridiculously expensive ($80.00 for a paper-bound copy/$89.00 for hardbound).

But, gentle reader, do not despair. I have also produced an eBook for the iPad and a .pdf format for other eBook Readers—The price? A mere $9.99, delivered direct to your device! To order, just click the link, the photo on this post or on the icon in the left column on this blog.

Tuesday, February 2, 2016

Virginia Rail

On 20 May 2015, John Holden and I discovered a Virginia Rail at nearby Sprague Lake. These rails are common, but often hard to see, in local marshes. This individual was fearlessly guarding its territory from us. A rail is able to navigate through the reeds because of its laterally compressed body and flexible vertebrae. Perhaps because of these adaptations, Virginia Rails survive flightlessness during the late summer, when they simultaneously molt their wing and tail feathers (Conway 1995).