They're a sure sign of spring in Yukon — and like the season, the migrating trumpeter swans seem to be arriving a bit earlier this year.

The last week has seen a growing flock at Swan Haven, a migratory rest stop at M'Clintock Bay on Marsh Lake, south of Whitehorse. 

"Last night, 200 swans were counted, which is well above average for the last couple of days of March," said Scott Cameron, a wildlife viewing technician with Environment Yukon.

"Those strong south winds could be easily blowing in more birds today." 

The shallow M'Clintock Bay is often ice-free earlier than other water bodies in the area, so it becomes a magnet for birds making their way from southern B.C. to summer breeding grounds in northern Yukon and Alaska — swans, but also ducks, geese, and other shorebirds.

Trumpeter swans

Swans and other migratory water birds typically stop for a rest at M'Clintock Bay, where there's usually open water by early April. (Jukka Jantunen)

"This is a rest spot for them, so they can feed, get some energy back, and this open water is where they do that because they eat plants that grow in it," Cameron said.

The Swan Haven Interpretive Centre, where bird-lovers can see and photograph the massive flocks, opens at the beginning of each April. Swan numbers typically peak in about mid-April, but Cameron said the early arrivals suggest the peak may be earlier, too.

"Every day, we're going to do a count of the swans and every other bird," Cameron said.

The results will be posted on Environment Yukon's website.

The Swan Haven Interpretive Centre opens for the season on Friday, April 1.

with files from A New Day