Audio clip
Kevin Calhoon
Two great blue herons are standing out among all the others in the Chattanooga area, and it's not because they're a beautiful blue. Rather, it's the lack of color that is attracting bird lovers' attention.
A white morph great blue heron took up residence near the Chickamauga Dam in early June, and another is living in a cattle pond in the Hixson area. Observers say they see the birds every day.
This is the first time a white morph has been spotted in East Tennessee and only the fifth time one has been seen in Tennessee, according to bird enthusiast Harold Sharp, a member of the Riverwalk Bird Club.
"It's native to South Florida and seldom seen north of the Everglades," he said.
Kevin Calhoon, assistant curator of forests at the Tennessee Aquarium and statistician for the Chattanooga Chapter of the Tennessee Ornithological Society, said the most likely scenario for the white morphs' appearance in town is post-breeding dispersal, an act that pushes baby birds out of the nest.
FAST FACTS
* Though it's very rare to see a white morph great blue heron in the area, there are three large, white wading birds that are seen more often during the summer -- the great egret, cattle egret and snowy egret are occasional visitors. Also, little blue herons are white until they turn blue during their second year. None of these birds breed in this area.
* In addition to great blue herons, there are also two other herons that breed in Southeast Tennessee: green herons and yellow-crowned Night-herons.
Source: Kevin Calhoon, Tennessee Aquarium
"And many times, they don't know where to go," Mr. Calhoon said. "They like marine habitats and salt water, though. That's why it's odd to have one here."
Great blue herons always have been residents of Tennessee, Mr. Calhoon said, but in small numbers. It wasn't until the area's rivers were dammed, beginning in the late 1930s with construction of Chickamauga Dam, that their populations exploded. The dams created wetlands and other good habitats for herons. Now, great blue heron rookeries can be found all along the Tennessee River and surrounding tributaries, Mr. Calhoon said.
The chances of the white morphs staying in the area and breeding here are slim, he said.
Though their bills are thicker and the difference in color is obvious, white morphs are considered the same species as the blue heron by the American Ornithologists Union.
"They have the same DNA, and they interbreed with blue herons," Mr. Calhoon said.
But they will breed only in the Florida Keys, Everglades, the Caribbean and Northern Mexico, where both white morphs and great blue herons live in abundance, he said.
Or login with:
New Account