Great Blue Herons missing from Samish Island nesting ground

by Anacortes American reporter Jacqueline Allison jallison@goanacortes.com

Skagit Land Trust is asking the public to keep an eye out for a great blue heron colony that abandoned its historical nesting ground on Samish Island last summer.

The heron colony, comprised of hundreds of birds, suddenly left the Samish Island site last June and has yet to return for nesting season this spring. The Land Trust has monitored the Samish Island colony since 2011, and a second large colony on March Point since 1992, according to Land Trust Conservation Director Michael Kirshenbaum.

“It’s the first time we’ve seen that happen in the years of involvement with both heronries,” he said. “We heard it does happen at other heronries.”

Herons are known to relocate due to predation, human disturbances and food availability, and may return to a colony up to 10 years later, according to the state Department of Fish and Wildlife.

Over a three-week period in June before the herons left, volunteer citizen scientists observed multiple causes that may have disrupted the birds, said Anne Winkes, member of a group that has monitored blue heron feeding and nesting around Fidalgo Bay since 2013.

Winkes pointed to several possible triggers, including tanker traffic and fumes, smoke from forest slash burning, a traffic accident, gunshots, eagle predation and more.

The chicks were newly hatched, so it was an unusual time to take off, she said.

“There were so many potential causes that it was hard to determine which was the triggering event or if it was cumulative,” Kirshenbaum said.

Last year, the Land Trust counted 800 nests between the two heronies as part of an annual survey.

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