OTTAWA, Jan. 8 (UPI) -- Researchers are blaming global warming for the big drop in Canada's boreal duck population -- scaups and scoters -- since the 1970s.
The ducks' numbers have plummeted by the millions in the past few decades and Ducks Unlimited Canada researcher Stuart Slattery told the Canadian Broadcasting Corp. Friday scientists think it's because climate change is affecting their food supply.
Slattery and other scientists from the University of British Columbia, the University of Saskatchewan and Environment Canada found that over those decades, spring has started coming an average of 11 days earlier. That warming trend influences when the ducks migrate south in the fall and affects the hatching of insects they rely on when they return in the spring to nest.
With spring now arriving much earlier, the ducks are missing out on their traditional food supply.
"As this mismatch gets worse, the ducklings are impacted the most," Slattery said. "The food just simply isn't there in the amounts that it was historically."
He said other duck species, such as the mallard, have shown signs of adapting but he suspects the scaups and scoters have not.
"They just get here late, and so they don't have a chance to re-nest like some of the other earlier nesting species do," he said.
Scaups and scoters nest throughout Canada's western boreal region, from Yukon and Northwest Territories to northern British Columbia, Alberta, Saskatchewan and Manitoba.
The researchers' report was first published in the online edition of the journal Global Change Biology in October.