Even before Harry Potter’s pet Hedwig made them famous, snowy owls were beloved by birders and had their place on every life list. These gorgeous predators of snowy tundras make their appearance every winter in Canada and the northern United States, and some years have far more spottings than others. These years are known as irruptions, and they’re a great time to seek out a snowy owl or two. Here’s what you need to know.
What causes a snowy owl irruption?
A bird irruption is generally described as a large number of unexpected birds in an area. Often, they are migratory birds that suddenly extend their range much further south or in much larger numbers than usual. Snowy owls are a good example of this. They spend the summer hunting and breeding far north of the Arctic Circle, and then spread out and move south into Canada and the northern U.S. in winter. In irruption years, snowy owl counts are much higher than normal, and sometimes they’re seen much further south. These irruptions happen every few years, with mega-irruptions occurring much more infrequently. (The 2013-14 winter was a mega-irruption; snow owls were spotted as far south as Northern Florida!)
One of the causes of snowy owl irruptions is related to their diet, but not in the way you might think. Snowy owls are carnivores, feeding large amounts of lemmings, voles, and other small rodents to their young during nesting season. When these rodent populations are thriving, snowy owls can raise more owlets. This means a population boom, and the birds have to move further away from their breeding grounds to find enough food for all. Generally, a snowy owl irruption is indicative of a strong population.
Where are snowy owls being sighted?
The winter of 2017-18 has brought another irruption of snowy owls, partly due to a banner breeding year in northern Quebec. New England seems to be benefiting most from this year’s irruption, but snowy owls are being seen in larger than usual numbers across Canada and the northern U.S. The best way to find out if these owls are being spotted near you is to check eBird using a species search. You might also want to check in with your local Audubon Society chapter.
Another way to learn more about snowy owl sightings is to follow Project SNOWstorm. This ambitious project tracks specific owls throughout their range, and uses data provided by citizen scientists to understand more about their behaviors. Their website offers interactive maps, snowy owl information, and regular blog posts about progress, conditions, and more. Find out more at projectsnowstorm.org.
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