June 19, 2013
Written by Jack Sanders
Thursday, 18 August 2011 11:07
Ever wonder how many kinds of birds there are?
The International Ornithological Congress says at least 10,448, but that will change. It’s some 500 species more than were recognized just 10 years ago.
Even today, new species are discovered, usually in a remote jungle of the Amazon region or in the Far East. However, most changes in lists result from re-categorizing known species.For instance, ornithologists could decide a bird that had been considered a subspecies is actually a species of its own. In 2002, the American Ornithologists’ Union agreed that birds that had been classified as the Dark-rumped Petrel were actually either of two new species: the Hawaiian Petrel or the Galapagos Petrel. Many of these new species are the result of examination of the DNA of the birds.
Another example of change involves the popular bird that was long called the Baltimore Oriole. Ornithologists had classified this bird and a western cousin called Bullock’s Oriole as separate species. However, when forests began to extend and connect in parts of the Great Plains, the two species came together in some areas, and scientists found that they were mating with each other. Successful mating was considered an important characteristic in deciding whether birds belong to the same species. The scientists then decided that the Baltimore and Bullock’s Orioles were really races of the same species, and renamed both the “Northern Oriole.”
The disappearance of the name Baltimore Oriole saddened or even outraged countless birders — and probably Maryland baseball fans — who had grown up with the old name; many flatly refused to acknowledge the new name. Some ornithologists disagreed, too, and subsequent DNA testing determined that the eastern and western races were indeed separate species. In fact, Bullock’s was more closely related to a Mexican species, called the Streak-backed Oriole, than to the Baltimore. So Baltimore and Bullock’s have returned to their former status as separate, though similar, species.
The Tufted Titmouse, a staple of eastern birdfeeders, was a few years ago split into two species, the Tufted Titmouse and the Black-crested Titmouse. The latter had formerly been a race of the Tufted, found in south-central Texas. While the two look a bit different, scientists also discovered they are also genetically and vocally different.
One of the grand debates among North American ornithologists has been the Red Crossbill, a finch found in the northern parts of the continent. Nine different “forms” or subspecies of this bird have been recognized. Some scientists, however, maintain that these forms are different enough in their appearance, vocalizations and feeding habits to be classified as nine separate species. The battle still rages.
Regional lists, such as that of the American Birding Association, can change for another reason. The association’s count of species north of the Mexican border has gone from around 925 10 years ago to 969 today, partly because of changing ranges. Birds that were once found solely in Mexico and parts south may work their way northward and across the border. The common Cattle Egret came from Africa, flying across the Atlantic to South America, and then working its way north.
Still another source of new species on regional lists is introduced birds. The European Collared Dove, now found widely in the Southeast, and the Monk Parakeet, a native of South America now common on the shoreline of southern Connecticut and locally elsewhere, wouldn’t have been on any North American bird list a century ago.
Species may also be removed from lists. DNA testing, for instance, might suggest that one species is really just a race of another. This is called “lumping,” as opposed to “splitting” a species into two.
A tragic cause for removal is extirpation. Some species disappear, usually because humans have either destroyed them or their habitat.
Birding with Luke Tiller: Sunday, Aug. 28: Westport Shorebirds, 1 p.m.; Saturday, Sept. 17: Trout Brook Valley, Easton, 7:30 a.m.; Sunday, Sept. 25: Westport Warblers, 7:30 a.m.; Saturday, Oct. 8: Allen’s Meadow and Secret Hotspots in Wilton, 7:30 a.m.; Saturday, Oct. 29: Sparrow Big, 7:30 a.m.; $10 each; To register visit www.sunrisebirding.com/walks.htm
Birding for Beginners, everything you wanted to know about bird watching, but were afraid to ask, with Luke Tiller, Saturday, Sept. 10, 7:30 to 10:30 a.m., $15, Audubon Greenwich, 613 Riversville Road, Greenwich, 203-869-5272 x221 greenwich.audubon.org
Birds in their Habitat art exhibition and sale, featuring bird carver Floyd Scholz, Sept. 23 to 25, Connecticut Audubon, 2325 Burr Street, Fairfield, 203-259-6305, ext. 407.
HawkWatch Weekend and Green Bazaar, live birds of prey shows, kids activities, food, eco-friendly businesses, more, Oct. 1 and 2, 11 to 5, Audubon Greenwich, 613 Riversville Road, Greenwich, 203-869-5272 x239, greenwich.audubon.org.
Copyright 2011 by Jack Sanders. Send sightings or comments to: jackfsanders [at sign] gmail.com, or to Bird Notes, Box 1019, Ridgefield, CT 06877. If you need help identifying a bird, try your local nature center. If you find an injured bird, call wildlife rehabilitator Darlene Wimbrow of Redding, 203-438-0618, Wildlife in Crisis of Weston, 203-544-9913, or Wild Wings of Greenwich, 203-637-9822. The columnist’s website is www. sandersbooks. com.
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