Officials with the enforcement branch of Environment and Climate Change Canada (ECCC) are investigating an alleged case of mass cliff swallow nest destruction at Walnut Beach Resort in Osoyoos, B.C.

The investigation began in early July, according to Ross Dolan, acting regional director for the wildlife enforcement directorate, Pacific and Yukon region, ECCC.

"Typically the type of nesting complaints we get are for smaller colonies," said Dolan. "So something like this, when you receive information about 150 nests, definitely that's something that we'll take very seriously."

The complaint lodged with the Canada Wildlife Service, the provincial ministry of Forests, Lands, Natural Resource Operations, and the B.C. SPCA by a guest at the resort specified that the remains of 148 nests were counted, with 35 nests left intact on July 1.

Swallows are in steep decline in Canada and according to the conservancy group Nature Canada, the cliff swallow population in B.C. has dropped by nearly 90 per cent since 1970.

They're protected by the Migratory Birds Convention Act, and destroying nests with eggs, nestlings, or adult birds can result in warnings, fines, or prosecution.

Walnut Beach Resort is accused of removing nearly 150 cliff swallows nests during nesting season. (Google Streetview)

Last year, a lodge in Banff National Park was fined $27,000 after maintenance staff removed and destroyed an egg and four barn swallow nests.

Myles Lamont is a Surrey-based wildlife biologist familiar with the complaint of destroyed cliff swallow nests at Walnut Beach Resort.

He said the alleged breach of the Migratory Birds Convention Act is one of the largest he's aware of.

"It's a disgusting thing to even think about," said Lamont, who added that the nests were all being used by the colony this season, so hundreds of eggs, hatchlings, and grown birds would have been killed when the nests were removed.

Lamont said the appropriate way to deal with an unwanted colony of cliff swallows would be to wait until after nesting season, remove the nests, and install nets or other deterrents to keep the birds from re-establishing their colony in the same place the following year.

'It's not correct'

Don Brogan, general manager of Walnut Beach Resort, said he's aware of the incident, but that the account reported to authorities wasn't accurate.

"It's not correct, but I can't comment on it. It's under investigation," said Brogan.

"I've been instructed by legal advice to say I have no comment, but yes, there were no birds destroyed," he said. "But it's under investigation and I can't make a comment. Sorry."

Dolan said the ECCC enforcement branch is kept very busy with complaints of disrupted nests during nesting season, with new calls about different birds covered under the Migratory Birds Convention Act nearly every day. But he said most complaints are regarding a single nest or smaller colony, so this case stands out.

"Something of that scale is unusual. That's not the type of daily occurrence that we receive," he said, adding that he couldn't say when the investigation is expected to wrap up.

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