"It's a funny place to set up a spotting scope," allows Richard Swanston, an avid amateur birder for the past 35 years. "The whole place shakes when a train goes over."
The subject of his attention this overcast afternoon is equally unusual - the first known nesting colony of Caspian terns in B.C.
Swanston positions himself on the paved pedestrian and cycle path that parallels the Canada Line bridge over the north arm of the Fraser River. The lanky naturalist then trains his 60-power scope on the silver metal roof of the Fraser River Terminal Inc. warehouse, just to the west, in Richmond.
"Have a look," he encourages. "You can't miss them, they're gorgeous."
What seems like nothing more than a bunch of noisy gulls in the distance now comes into sharp focus.
Caspian terns are striking birds with black heads, red bills, grey wings, white bodies, and a hoarse, cackling call.
Swanston has counted more than 300 terns here, a figure he doubles to account for birds on the far side of the roof which are out of view.
In addition to the regular presence of Canada Line passenger trains, commercial jets fly low above the River Rock casino on approach to Vancouver International Airport, motor vehicles hum across the Oak Street Bridge just downstream, and tugs haul barges loaded with wood chips.
But the industrial nature of the nesting habitat is the least of the terns' problems.
Swanston has yet to see an egg hatch, and speculates that avian predators such as glaucous-winged gulls, which nest on the roof of the adjacent building, and crows are at fault.
"They won't be successful," he predicts. "Every egg is taken."
Occasionally, something spooks the terns and they all take flight, carving out a circle in the grey sky before returning to the roof. "I think they're desperate for a place to nest," says Swanston, adding that if and when summer arrives, the heat on the roof could also bake the eggs.
Caspian terns are summer migrants to B.C., flocks are typically observed feeding or flying overhead in south Delta, near the Tsawwassen ferry terminal. But never before have they been found here as a nesting colony.
Mike Boyd, a consulting ecologist and Vancouver director of the conservation group, WildResearch, discovered some Caspians flying up river while working at Iona Island on May 19.
Several carried fish, often used in courtship rituals.
"They're very amorous," explains Swanston, a retired Tsawwassen resident. "The male will have a fish and will dip his head on each side of the female. A lot of posturing and plumping up of feathers. They do a lot of copulation."
It was Boyd who first tracked the terns to the roof at Fraser River Terminal, where he observed courtship behaviour, attempts to build nests, and one egg. Several more eggs followed.
He confirmed it was indeed B.C.'s first nesting colony.
According to the guidebook Birds of B.C., the only record of breeding terns in the province involved one pair at Roberts Bank in 1984.
Boyd said some of the terns present at Fraser River Terminal have been observed with coloured leg-bands from East Sand Island, near the mouth of the Columbia River in Oregon.
The man-made island is the largest known Caspian tern nesting colony in the world, with more than 8,000 pairs.
Joe Meche, outgoing president of the Cascades Audubon Society, said it is likely the terns are settling in Richmond after getting kicked out of the old Georgia-Pacific pulp mill site on the downtown waterfront in Bellingham, Wash.
About 250 terns settled there in 2009, with the population increasing to more than 3,000 in 2010 before the Port of Bellingham stepped in.
"They saw them as an impediment to development of the property," he said, describing the terns as adaptable and resilient. "I would imagine that birds from this colony are dispersing and looking for new nesting possibilities, whether it's a rooftop or open beach, whatever works for them."
Caspian terns are among 11 species of birds that prey on at-risk Chinook salmon and steelhead on the heavily dammed Columbia River. U.S. officials over the years have resorted to various measures, including reflective tape, pyrotechnics, or even shooting the birds to reduce their impact during the out-migration of smolt.
The International Union for Conservation of Nature lists the Caspian tern as a species of least concern.
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