Lethal dose: Redhead ducks test positive for red tide toxin

By MARK REAGAN/Special to the Star

SOUTH PADRE ISLAND — Fishermen working here recently saw five ducks fly directly into a building, killing themselves.

Another 120 dead ducks were found over the past six weeks.

The birds’ carcasses were sent to a lab in Corpus Christi where biologists found the tissue contained brevatoxin, a potent neurotoxin associated with red tides.

Island Coastal Resources Manager Reuben Treviño said since the onset of red tide in September and October, gulls and pelicans have died, but the death of redhead ducks is abnormal. It isn’t immediately clear how the waterfowl are contracting the brevatoxin, he said.

“Redhead ducks winter here because of the sea grass. It’s what they feed on,” Treviño said. “So our next step is to collect sea grass samples from around the bay to determine if they are getting sick through the food web.”

The dying ducks aren’t limited to South Padre Island’s waters. The entire 367-mile Texas coast is affected and reports of birds dying span the length of it.

The dead ducks first began appearing at a pond in front of the Pearl South Padre Hotel, an area where the ducks rest after feeding.

When the waterfowl are poisoned they display erratic behavior, such as flying in circles or letting humans approach them. The birds have also reportedly flown into power lines.

 “And we wondered, is that really the problem? The power lines have been there for 20 years and it has never been an issue before,” he said.

And that’s why Coastal Resources had the carcasses tested, which showed the elevated levels of brevatoxin.

In conjunction with AEP Texas and Time Warner Cable, the city of South Padre Island has installed safety markers on existing overhead lines that may be associated with the bird’s death.

If the brevatoxin is in the sea grasses, there’s nothing that can be done to remedy it except to wait as the brevatoxin will eventually work its way out of the food chain, Treviño said.

 “It’s a natural process and that’s how things play out sometimes,” Treviño said. “It’s a matter of monitoring and being aware of the ecosystem so we have a better understanding of it, period.”