The deaths of dozens of seagulls this week in Casco Bay may have been caused by avian flu, a Maine Audubon scientist said Thursday.
Photos of the dead birds suggest avian flu was the likely culprit, but the birds must still be tested to be sure, said Doug Hitchcox, staff naturalist for Maine Audubon in Falmouth.
“It’s very likely that it was avian flu, but until there have been some tests done, I wouldn’t want to jump to that conclusion,” Hitchcox said in a telephone interview Thursday evening. Hitchcox said climate change is disrupting Casco Bay ecosystems and there could be other factors involved.
“There are enough unknowns that I wouldn’t want to jump to conclusions,” he added.
A local woman cruising in a boat near Mink Rocks, just east of Cliff Island, took photos of the birds this week. Hitchcox identified the birds as great black-back gulls, a species vulnerable to the virus. Mink Rocks is most likely a nesting colony for the great black-back gulls, which Hitchcox said are the world’s largest gulls.
Great black-back gulls are described by the Cornell Lab of Ornithology as aggressive hunters, pirates and scavengers. Herring gulls are smaller and are the ones commonly seen on beaches.
The woman who reported the deaths, Shannon Silverson, could not be reached Thursday, but she told WGME-TV she saw a large seagull flopping around and took photos.
“It was obviously sick,” Silverson told the TV station. “I turned around and all of a sudden I saw another, and then another one, and another one. There was probably 30 (gulls), some alive, some dead. I’ve never seen anything like it.”
Silverson contacted the National Oceanic and Atmospheric Administration, according to Ainsley Smith, NOAA’s marine mammal stranding coordinator. Smith said she referred Silverson to the U.S. Department of Agriculture, which tests birds for the virus. Smith does not know if the USDA tested any.
“While it’s unfortunate, it is not surprising based on what we’ve been hearing from other states,” Hitchcox said.
Earlier this week, authorities reported a massive bird kill on Martha’s Vineyard in Massachusetts. The Associated Press reported that hundreds of dead cormorants washed up on the island’s shores, and officials said the deaths may have been caused by a highly contagious strain of avian flu.
The animal control officer for the town of Tisbury, Massachusetts, said it could take years for the cormorant population to recover on the island. The officer urged residents not to touch the birds and to keep dogs on leashes. Many of the dead birds were floating in seaweed.
Earlier this month, avian flu decimated the world’s largest colony of northern gannets on Bass Island in the Firth of Forth off the coast of Scotland, Hitchcock said. Tests by Scotland’s Department for Environment Food & Rural Affairs on a few of the gannets showed they were infected with avian influenza, according to the BBC.
Earlier this year, there was an outbreak of highly pathogenic avian influenza (HPAI) among Maine’s domestic poultry flocks, but Jim Britt, a spokesman for the Maine Department of Agriculture, Conservation and Forestry, said the number of backyard bird cases has waned dramatically.
“We haven’t received any reports of bird flu for months,” Britt said Thursday.
The last reported case of HPAI in the Northeast was in Vermont on April 29, according to the Maine department’s website. The risk of domestic birds contracting the virus from wild waterfowl remains high, and the state continues to urge flock owners to shelter or separate their flocks from wild birds.
There has never been a case in Maine of a person becoming infected with the avian flu.
The Maine agriculture department said the onset of summer weather could help blunt the spread of avian flu.
“Sustained hot, dry weather coinciding with decreased movement of wild waterfowl populations is expected to benefit HPAI control efforts,” MDACF said.