One thing about studying a species with cyclical or irregular movements, like snowy owls, is that every once in a while you hit a dull stretch. And in the East and upper Midwest, where Project SNOWstorm primarily works, it’s definitely one of those winters.
So far, there have been only a handful of snowy owls reported from the western Great Lakes east to southeastern Canada, New York and New England. Usual hotspots like the Ottawa River Valley in southern Ontario have one or none being reported on eBird (which won’t pick up every snowy owl, but will show most of them). None of our six previously tagged owls from last winter has shown up in cell range yet, including Otter, whom we were able to track all summer using the Argos satellite portion of his hybrid transmitter. (That story is here.)
In fact, you have to go back to the early winter of 2010 to find a year with so few snowy owl reports in eastern and central North America. The Audubon Christmas Bird Count (CBC) tallied just five snowy owls continent-wide that year. While this isn’t a lot of fun for those of us hoping to have lots of white owls to liven the winter landscape, such off-years are most likely just part of the periodic boom and bust in snowy owl breeding ecology. Occasionally you get a summer when there was a widespread lack of lemming production in the Arctic, and thus a poor breeding season for the owls and fewer young birds coming south.
That this isn’t usually a permanent state of affairs is reflected by what happened in 2013, just three years after that painfully slow winter. A lemming mega-boom in northern Québec sparked the biggest irruption of snowy owls in memory the winter of 2013-14, and also sparked the creation of Project SNOWstorm. (That year, some 336 snowies were counted on the CBC.)
There have been more snowies appearing in the Canadian prairies this year, but our colleagues there report they are almost all adults, and those they have been catching have been in fairly poor body condition, which also suggests this was a low year for small mammals in the central Canadian Arctic.
The unusually mild winter weather so far, perhaps fueled by a powerful El Niño, may also be conspiring to keep owls farther north than normal. If there is one darker uncertainty, though, compared with earlier off-years, it’s the possible effects of highly pathogenic avian influenza (HPAI), which emerged two winters ago and which we know has hit snowy owls fairly hard. We suspect HPAI is the reason so few of our previously tagged owls returned last winter, and while we suspect this winter’s poor showing is more likely a normal dip in the periodic boom and bust, we can’t be certain avian flu isn’t exacerbating it.
In the past week or so, a few more snowies have shown up in the East, so we may a late push, especially if we get some cold and snowy weather to the north. Our tagging teams are ready if owls appear in their areas, but in the meantime, there’s not much to do but wait. In long-term studies like SNOWstorm, we have to remind ourselves that seemingly dull winters like this one are as important to understanding the dynamics of snowy owls as the busy, exciting ones.