As expected, many of the Buffleheads left last night as the pressure rose. It has just passed the peak at 1028 hPa, and it’s clear and calm. There are still fifty remaining, including an adult drake of a pair, and expect that more will depart tonight.
This departure date is the same as last year and 2012, and heralds a warm spell that will develop over the interior through the next week. Temperatures in the Mackenzie Valley are forecast to reach 18 degrees by Monday, so the snow will be retreating rapidly.
There are still a few other late lingering compatriots, including Red-breasted Mergansers (13), Surf Scoters (17), Red-necked Grebes (4), and one Horned Grebe. Like the Buffleheads most of these are yearlings and non-breeders, in various stages of moulting into adult plumage. It’s always a toss up between the Buffleheads and Mergansers to see who will linger the longest.
One of the essential characteristics of the Bufflehead’s life can be summed up as “Last to Depart, Last to Return” (from winter habitat), a phenological fact related to their small size and ecological requirements.