The last Buffleheads, five yearlings, left last night, along with two Goldeneyes, but the Surf Scoters (8) are still hanging on.

That’s a total of 214 days since their first appearance on All Buffleheads Day, which amounts to 58% of the year. However if you exclude the narrow shoulder season, their winter season amounts to 54 %, or nearly half the year.

The chart of their occupation period shows some typical characteristics as well as some atypical features, some of which are related to El Nino weather conditions. Most notable was their rapid mass arrival and strong peaks before the onset of a series of Sou’easters beginning onNovember 12th. Numbers remained unusually high as many engaged in co-operative feeding at the mouth of the bay between Nov 25th and Dec 5th. Numbers peaked again in late February – early March.

The departure schedule began early as the breeding pairs left during an extreme warm spell in mid-April, but the yearlings left around the usual time, except for a few that remained quite late ( i.e. yesterday).

That’s the phenological signature of El Nino 2016, as the oscillation turns into the La Nina phase. Only 152 days left until ABD.