By Shelby Sebens
PORTLAND, Oregon (Reuters) - Oregon agriculture authorities are investigating the mysterious deaths of potentially thousands of honeybees along a highway, the second die-off of bees in the state in less than a year.
Officials said on Wednesday that they did not reach the site along highway 99 in Sherwood, a small city southwest of Portland, in time to document the precise number of bees.
"From what I've learned, when bees swarm, there can be anywhere from one to 10,000 in a swarm, so if that indeed was a case of a swarm of bees in the area, it could be in that range," said Oregon Department of Agriculture spokesman Bruce Pokarney.
He said officials saw dead bees in the roadway or shoulders of the road. A witness told a news station thousands of dead bees were found on Sunday.
With global reports of dwindling bee populations, deaths tend to stir emotion and concern from environmentalists and the public. The U.S. Department of Agriculture says on its website that the number of managed honeybee colonies in the country declined from 5 million in the 1940s to 2.5 million today.
Pokarney said there was no indication the honeybees in Sherwood were harmed by pesticides. Investigators found 48 commercial hives nearby and they were "thriving," Pokarney said.
"We have a lot of crops that rely on pollinators. It's important to maintain the health of our bee population," he said.
Officials' working theory is that the bees swarmed, tried to cross the busy road and ended up as roadkill, and that the owner of the bees may have simply had too many at the site.
But Pokarney said the department has nevertheless sent some samples from the Sherwood hives to Oregon State University to check for possible disease or other issues.
The die-off was the second this year in the state, after 50,000 bumblebees were found dead in a parking lot in Wilsonville in June. They were later determined killed by pesticides and the company at fault was fined.
(Editing by Cynthia Johnston and Grant McCool)