By Jean-François Therrien
Every year since the late 1980s, a group of researchers of which I feel lucky to call myself part has headed north to the high Arctic — as do snowy owls — to monitor their summer breeding areas.
Our long-term study site is on Bylot Island in Nunavut, Canada, at 73 degrees north, above Baffin Island. It has seen several lemming and owl outbreaks over the last 25 years, but because lemming and owl numbers fluctuate tremendously annually, you never know what you are going to get.
Indeed, during the summer of 2013 Bylot Island had very few lemmings to offer, and as a result, no owls were seen. Instead, lemmings were plentiful in the Salluit region in northern Quebec, Canada, at around 62 degrees north — more than 1,200 km (760 miles) south of Bylot.
This high lemming density attracted many snowy owl pairs and they most likely all succeeded in raising large families (the average clutch size was 6.6 eggs). Such large numbers of birds produced in the short Arctic summer triggered the amazing winter irruption that began a year ago, and we believe that most of the snowies we saw down at our latitudes last winter were born in that region. You know the rest of that story.
In June 2014, we were back on Bylot Island, and our team found a snowy owl’s nest less than 24 hours after stepping on the island. We were of course pretty excited to see this; a snowy owl breeding year is always an exciting one. But what we found as we began exploring caught us by surprise.
In a core study plot of 100 km2 (39 square miles) that has been systematically searched every year since the late 1980s, the previous record number of nests was 13, found in 2004. This summer, we were thrilled to send that record to the archives when we found 20 active nesting pairs in the same study plot. Such density had never been recorded on Bylot Island before!
Overall, including a larger portion of the Island, the total number of nests found was 116, surpassing the previous total of 33 nests found in 2010. These owls had plenty of lemmings to eat, but the availability of food didn’t seem to be as great as in 2013 in the Salluit region, so the number of fledglings might be lower than what was seen during summer 2013.
Moreover, Bylot Island is located roughly 1300 km (800 miles) farther north than the Salluit region where the breeding occurred in 2013. So, to come to our latitudes, young owls will have to travel much farther before showing up in our neighborhoods.
Given the high density of nests, we are nonetheless expecting to see some snowy owls this winter, but we’ll have to wait and see if the numbers get close to what we had last winter. However, exciting early reports (as of 17 Nov.) of snowy owls have already come in from southern Quebec, Massachusetts, Pennsylvania and Maryland, to name only a few places. The 2014-15 winter story is about to unfold before us. So grab your binoculars and long-johns, and let’s get ready to head out!
(SNOWstorm team member Jean-François Therrien is a senior research biologist at Hawk Mountain Sanctuary in Pennsylvania, and has been studying snowy owls in the Arctic for years with Laval University in Quebec.)