Monday, April 16, 2007

D.C. Rare Birds, Now and Then

From time to time I check through the search phrases that have brought visitors to my blog. One recent search that caught my eye was for the phrase "dc rare birds." Now, a list of rare birds for the District could be generated in various ways depending on the criteria involved - birds rare everywhere, birds rare in the U.S., birds common elsewhere but rare in the District.

Out of curiosity, I did a search myself on that phrase to see what it would produce. Among the many listings for "rare bird alerts," I found a two-page note from an old edition of The Auk (pdf). This report is from E. M. Hasbrouck, who seems to have been an ornithologist associated with the U.S. National Museum. It provides a look into a different world of ornithology as it was practiced at the end of the nineteenth century.

Rare Birds near Washington, D.C.--The spring migration, which is reasonably productive here about once in every four years, was remarkably so in 1892 , in the number of rare and desirable birds it brought to local collectors. For the first three of the following records I am indebted to Mr. Frederick Zeller, a professional gunner, whose almost constant presence on the marshes, and excellent knowledge of local birds, enables him to detect and capture new or uncommon species in the District.
The note goes on to list the species collected, including the date and place of collection. The following is typical:
Empidonax pusillus traillii.--This has always been regarded the rarest of the Flycatchers, very few having been taken up to the present year. On and about May 25, for several days, they were quite common, and a number were taken by the collectors.
The above appears to be an alder flycatcher (Empidonax alnorum), part of the species complex formerly known as "Traill's Flycatcher." My source for that is a supplement to the AOU checklist from The Auk in 1876. Alder flycatchers do seem to be the least likely flycatcher to be reported in the District. I suspect that the difficulty of identification has as much to do with that as genuine rarity.

Reading about the killing of a very rare species like an alder flycatcher comes now with a touch of irony. That was the way things were done before high-quality binoculars and mist nets. For another example, you would not see the following in a rare bird report today:
While walking along an old cattle trail, I flushed a bird from a nest containing five eggs directly beneath my feet, and shot her to be sure of identification.
The passage above refers to a Kentucky warbler found outside D.C. It is one of two sightings reported for that species in the article. Reports of a yellow-headed blackbird (Xanthocephalus xanthocephalus) in the District and "a large colony" of Henlow's sparrows (Ammodramus henslowi) 16 miles from D.C. are tantalizing. One generally needs to go much farther today to see one Henslow's sparrow, let alone a large number. Here are the other birds mentioned in the note:
  • Tantalus loculator - Wood Ibis, now Wood Stork (Mycteria americana)
  • Gallinula galeata - "Florida Gallinule," now Common Moorhen (Gallinula chloropus)
  • Bartramia longicauda - Upland Sandpiper
  • Aegialitis semipalmata - Semipalmated Plover (Charadrius semipalmatus)
Several reports refer to mudflats in and near the District. These flats are mostly long gone now. In the early twentieth century, major changes were made to the Potomac and Anacostia. The rivers were dredged and levees were built, so that the rivers no longer look the way they did when E. M. Hasbrouck and his associates were collecting bird specimens a century ago.

For a current list of D.C.'s rare birds, see the local government's list of Birds in Greatest Conservation Need (pdf). Full report here.