Monday, April 6, 2009

A Historical Note on the Least Tern

"Despite its name, the least tern plays a very unique, important role in the tern family."
-Dr. John Bishop, Cornell Lab of Ornithology

Residents of the central Pacific coast recognize the friendly white-and-gray bird capped by a black helmet of feathers: Sternula antillarum brownii, the California Least Tern, a subspecies of the Least Tern (Sternula antillarum) species familiar on the Atlantic coast. The Least Tern, in turn, bears close relation to the other seabirds of the Sternidae family, and so on. Many tern species have names reflective of their discoverers (e.g., Jameson’s Tern or Cooper’s Tern) or characteristics (e.g., the Sooty Tern or Minor Iridescent Tern), but the Least Tern’s origins have remained as overlooked as its name suggests.

Naturalist Jonas Stern first identified the larger Tern family (Sternidae) in 1838 by classifying a series of similarly-countenanced birds along the Thames River. He abandoned his initial inclination to group these docile, web-footed, sea-feeding creatures as a subspecies of gull or duck when he noticed the distinctive feathering pattern that prevailed across all samples, a finding confirmed both by breeding patterns and a unique trilling tweet. Drawn to this masked bird, Stern spent the next four years scouring waterways throughout western Europe and the American Northeast in search of finer classifications, of which he determined many, all dwelling along the shores of rivers, lakes, and seas, and all with variations on the gray-black-white in their feathering.

Later, in 1850, ornithologist John James Audubon ventured west as the official naturalist of the Gold Rush, bringing with him his fondness for Stern’s avian discoveries. While taking an observation walk along the Pacific near the San Francisco Bay, Audubon came upon a flock of Terns unlike any previously studied, bearing bright orange bills and more streamlined feathering. A series of measurements determined this group as the smallest among known terns in length, with the shortest bills, and most concise songs. With measurables consistently last in the Tern family, Audubon dubbed his finding the Least Tern.

1 comment:

  1. Tern: this hits 1/3 NYTimes Crossword puzzles. Usually Wednesday 5 down