Monday, July 25, 2005

A Sultry Evening Twitch

A report on MDOsprey last night noted the presence of a yellow-crowned night-heron and a tundra swan, two locally uncommon species, near the Chain Bridge. The latter is not made out of chains, nor is there anything about it that suggests instability. I presume the name comes from an earlier version of the bridge. The Chain Bridge crosses the Potomac River and Chesapeake and Ohio Canal just inside Washington's border with Maryland. The walkway on the north spot looks down upon a series of ponds and meadows created by the rock formations in the river gorge below.

I debated with myself about whether to go look for these two birds. As likely as not they would not be around, I thought, and it was hot and the trip through Georgetown to the canal can be long at times. But I decided that two local rarities increased the odds enough, so off I went in the early evening. The bus dropped me near Fletcher's Boathouse around 7 pm, and I walked the half-mile or so from there to the Chain Bridge. The evening was hot and hazy. The thermometer sat around 92°F when I left and was only down to 89°F when I returned home; the humidity was about 60%. I could see the humidity in the thick haze that blanketed the river valley. Even though the sun was above the horizon, it was barely visible through the mix of clouds and haze.

Not many birds were stirring. I heard one pileated woodpecker and saw a wood duck with three ducklings in the same place I have seen a wood duck family for the past three summers. More wood ducks awaited when I mounted the Chain Bridge and began looking down into the ponds. The land below the bridge presents lush green foliage contrasting with the deep grays of the ponds and rocks, with the dark brown ribbon of the Potomac coursing just beyond. Within the meadows, white-tailed deer browse. As often as I have seen them there, they still can be a startling sight when I see their heads sticking up out of the grasses. The trees were alive with red-winged blackbirds and American goldfinches, while one gaudy yellow warbler wrestled with a caterpillar. About five green herons and three black-crowned night-herons patrolled the ponds. One first-summer night-heron bent over holding its bill in the water, presumably waiting for some fish to swim past.

Though I checked each pond carefully, I could not find the yellow-crowned night-heron. If I had, it would have been a year-bird and a DC-bird for me. As it is, the yellow-crowned night-heron will have to wait. This is one reason I tend to be reluctant to twitch; the cost in time and energy is quite high if I fail to see the reported species.

However, I did see the tundra swan. Tundra swans are fairly common along the east coast in winter; in the Washington area they winter along the Chesapeake Bay and in the Eastern Shore in great numbers. But the swans rarely come all the way up to Washington itself. (Even mute swans are rarely seen here.) My only other tundra swan within the district was last summer, on June 17.

This bird apparently showed up around May 15 of this year. This is clearly not a breeding individual since only one has been seen during the past two months. Most likely this swan chose not to make the long flight back to the tundra of northern Canada and Alaska, its normal breeding ground, and settled for the summer along the Potomac. I tend to think this is a first-summer bird because the head and neck were somewhat grayish. If tundra swans wait several years before their first breeding, as several other large species do, then this individual may be too young for breeding, and thus did not need to make the flight to the tundra. Unfortunately I was not able to confirm this breeding pattern in any of my books, though Frank C. Bellrose, in his Ducks, Geese, and Swans of North America, speculates that tundra swans wait to breed until their third summer.

This swan certainly looked out of place. I am used to seeing tundra swans on wide bays and lakes choked with ice, when I am bundled to stave off the cold, not in a small pond on one of the hottest nights of the summer. Tundra swans have as their scientific name cygnus columbianus, "dove-like swan." The white feathers and graceful shape contrasted sharply with the muddy embankment upon which it stood while it preened itself; grayish head aside, this bird's whiteness stood out like a beacon. And the swan was big; it easily dwarfed the wood ducks and green herons with which it shared the pond.

So was it worth the trip? Yes, even if I missed the main species I wanted to see. I had the opportunity to watch some herons at work, saw a swan that is unusual in Washington, and did those things in a beautiful spot. And that kind of combination is what keeps me birding.

Before sending this post to the server, I have to register a complaint. Washington, D.C., has many wonderful natural areas in addition to the more familiar memorials of the Mall. However, many of these natural areas are difficult to reach, either requiring long rides with multiple connections, or in places that are otherwise difficult to reach without a car. The C & O Canal is a case in point. Someone without a car has basically three choices to reach the canal. One is at the start of the canal in Georgetown. The other two are bridges across the canal at Fletcher's Boathouse and Arizona Avenue. The first requires a walk down a steep winding road without a sidewalk, followed by crossing the busy Canal Road without benefit of a stoplight near a blind curve. The second requires walking down a steep hill on a road, again without a sidewalk; at the end one has to walk up an embankment to reach a bicycle bridge to cross Canal Road and the Canal, and then walk down a steep embankment on the other side to reach the towpath. Neither of these is pedestrian-friendly. A city should not be this way.


Great Blue Heron
Green Heron
Black-crowned Night-Heron
Tundra Swan
Canada Goose
Wood Duck
Ring-billed Gull
Rock Pigeon
Mourning Dove
Chimney Swift
Pileated Woodpecker
Eastern Kingbird
Northern Mockingbird
American Robin
European Starling
House Sparrow
American Goldfinch
Yellow Warbler
Northern Cardinal
Red-winged Blackbird
Common Grackle