NEW ORLEANS (Reuters) - A few days after the deaths of 5,000 birds in Arkansas, Louisiana wildlife experts on Tuesday were investigating the deaths of 500 birds along a stretch of highway in Pointe Coupee Parish.
The Louisiana birds included red-winged blackbirds, the same type discovered dead in Arkansas.
While the deaths seem startling, a bird expert said these types of birds tend to roost at night in huge numbers, and a disturbance can easily cause some to be disoriented and collide with buildings or trees.
"It's not surprising if it's one or two events like this," said Melanie Driscoll, director of bird conservation, Gulf of Mexico and Mississippi Flyway, National Audubon Society. "These things happen."
The mix of blackbirds and starlings were discovered in two areas on Monday between New Roads and Morganza, Louisiana, according to Bo Boehringer, press secretary for the Louisiana Department of Wildlife and Fisheries.
Jim LaCour, a staff veterinarian for the department, found many birds showed traumatic injuries. Nearby power lines along the highway could be a factor, if the birds flew into them in darkness, according to the department.
Boehringer said birds were sent to labs in Georgia, Iowa and Wisconsin to find out how they died.
The Louisiana report comes after some 5,000 birds, mostly red-winged blackbirds, were discovered dead in Beebe, Arkansas on New Year's Eve. Tests by Arkansas veterinary officials concluded Monday they died after massive trauma.
One theory is that birds were spooked by New Year's fireworks and flew into buildings or other objects. Another theory is that severe weather caused the deaths.
"We're leaning more toward a stress event," said Arkansas Game and Fish Commission spokesman Keith Stephens, noting that severe weather had already left the area.
Driscoll said that birds like blackbirds and starlings roost in large congregations, of 100,000 or more. Compared to the size of the roost, 500 to 5,000 birds "isn't a big number," Driscoll said.
The Arkansas commission also is trying to determine what caused the deaths of up to 100,000 fish over a 20-mile stretch of the Arkansas River near a dam in Ozark, 125 miles west of Beebe. The fish were discovered December 30.
Stephens said disease may be the culprit, since almost all the fish were one species -- bottom-feeding drum.
Stephens said the Arkansas events do not appear related.
Writing by Mary Wisniewski, Editing by Greg McCune