99-01-30 14:19:26 EST By The Associated Press MER ROUGE -- Thousands of blackbirds are dying in north Louisiana and nobody seems to know why. For the past several weeks, Wanda and Daniel Hudson of Morehouse Parish enjoyed watching tens of thousands of blackbirds flying over their house toward Mer Rouge each morning. Each afternoon, they watched the huge flock fly back toward Log Cabin. Then Monday, the blackbirds started dropping from the sky into yards and ditches where they staggered and faltered, many making their way out to Louisiana 425. The dead and dying birds have been littering their yard and a five-mile stretch of nearby homes and highways ever since. About 50 birds lay dead in a stretch of a couple hundred feet from the Hudson's home. Others teetered on the highway's edge, dying. "It's really pitiful," Mrs. Hudson said. "They are coming into our yard and dying. "It takes them awhile to die. It's a slow, painful death." Hudson called the state Department of Wildlife and Fisheries in Monroe on Monday. "I've never seen it hit like this," said wildlife biologist Jimmy Anthony. "There are quite a few birds falling out of the air -- thousands." Anthony said the five live birds he collected Monday died that night. An autopsy revealed nothing. Tests are being made at Louisiana State University Medical Center to determine the cause, which Anthony said could be a virus or bacteria, pesticide or even a natural toxin on a food supply. "I just don't know," he said. "Sometimes these things stare right out at you, but this isn't one of them." Mrs. Hudson walked over to a blackbird sitting in her backyard. The bird didn't move with the approach of people. Its head lolled dizzyingly from side to side as it shook before attempting a few steps. Finally, it stopped, settled, and turned its beak straight up. He remained that way for another 10 minutes. "He's trying to breathe. It's how he gets air," Daniel Hudson said. "I've been in nature all of my life and I've never been able to walk up on a blackbird." He snapped his fingers in front of the dying animal. No response. The bird's rich teal and scarlet coat took on a yellow tinge. "He's been out here for hours like this, and he's likely to be out here a while longer," Mrs. Hudson said. "But then again, he may be near." The Hudson's say they are anxious to find the cause and whether it could be a health threat to other animals or humans. Already, Wanda Hudson has had to pull a dead bird out of her dog's mouth. "We have lots of cows and squirrels and other animals around here," Wanda Hudson said. "We have a lot of people with kids." Anthony said he doesn't think the birds present a health danger, but advises wearing gloves to remove them from yards. "Just don't handle them, wear rubber gloves to pick them up and place them in a plastic bag," he said. "Viruses (in birds) usually don't affect humans. "The only real threat to humans is if it bacterial."