In 2025 Project SNOWstorm, in cooperation with Hawk Mountain Sanctuary in Pennsylvania, contracted with Dr. Diego Gallego García of Argentina to conduct a post-doctoral analysis of an enormous set of spring and summer movement data from snowy owls in the Arctic and subarctic, working with Dr. Rebecca McCabe at Hawk Mountain. The initial analysis covered more than 40 individual owls from Project SNOWstorm, as well as owls tagged in Saskatchewan by our colleagues in Canada, who generously provided their data.

 Here, Dr. Gallego García provides a sneak peek at what they have been finding – while he pushes ahead with a further analysis of data from another 40 or so owls tagged in Canada by other colleagues in the International Snowy Owl Working Group. Once the full analysis is completed later this year, the results will be drafted into a paper to be submitted for peer review and publication in an appropriate journal, and we’ll be sharing aspects of the analysis that point toward areas in the Canadian Arctic that appear to be especially important for snowy owls with the Canadian Wildlife Service.

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Human beings have always been driven by the curiosity of the unknown, and by the search of purpose in life. In their intent for structuring what they see in the environment, humans have tried to design and create rules and laws in order to understand. However, not everything is easy to tally in the squared world of mathematics and logical thinking.

And maybe this is the case of the snowy owl, whose movements have astonished human for centuries. As many will probably know, this iconic and unique raptor species of the Arctic mainly relies on lemmings, small mammals that follow boom-and-bust population fluctuations every three to four years, during the breeding season. The occurrence and location of these outbursts can be challenging to monitor, but not for owls, which appear to settle in summer where these mammals appear. Or so we imagine, since it is difficult to follow them in such a vast and largely roadless ecosystem; therefore, the question remains a mystery, and we researchers tend to label their  movements as “nomadic,” probably as a way to hide our own inability to describe, model, or predict where they settle in summer.

But what if these owls are not wanderers during the breeding season? Attempts have been made to try to link their movement decisions to environmental information such as snow cover, but some behaviors are not that clear. Is it possible that snowy owls use past experience or memory to decide where to settle next, similar to so many other migratory species? And here is where the story starts for me, an early-career science globetrotter who, just like the owls, has been itinerant in the last few years and whose current task is to decipher these rolling stones.

So, what have we found so far? Well, I can tell you … these owls are challenging to study! Take a look, for instance, at the movement patterns of Wells, an adult female tagged by Project SNOWstorm with a GPS transmitter in 2017 in Maine, and that was tracked until 2021.

Spring and summer movement tracks of adult female “Wells,” from 2017 to 2021. Summer settlement areas of each year are indicated with a star. (©Project SNOWstorm)

In 2017, her spring migration ended in Ungava Peninsula of northern Québec peninsula, where she probably tried to breed, based on the time period and cluster of GPS points in a small area. In the following year, early in her spring migration, she made a decision that dramatically changed her northbound route; she steered away from the previous path and turned northwest, around Hudson Bay and up towards King William Island in Nunavut, arriving when most owls already had young in the nest. In 2019 she returned to the 2017 summering area, but likely saw something she did not like and continued her way northwest, arriving back on King William Island, but through a different flyway. And not only that, when she arrived at the island, she again was not convinced enough, and returned to a midpoint, again too late to nest. After these two “late summers” in Nunavut, next two years (2020 and 2021), Wells decided to follow the 2017 “Québec nesting plan.”

Apart from the expected 3- to 4-year pattern in the selection of summer settlement areas, it is striking how this owl appears to know something beforehand, when every year she wintered at the same place in Québec City but, at the middle of spring migration, took a different turn at the crossroad. What we do not know is whether the summer settlement areas in King William Island were assessed by Wells in the years prior to us tracking her.

Nevertheless, things get even more interesting when we study different owls in the same year. Focus now on the next image, where our aforementioned adult female, Wells, and an adult male named Outlook, tagged by Dr. Karen Wiebe in Saskatchewan in 2016, are shown, both during their spring-summer movements of 2018. While their wintering sites differ by more than 2,800 km (Saskatchewan and Québec), their summering sites are only 34 km apart. This seems to support the hypothesis that owls likely have some notion on what the ideal areas to summer are, before (or very early during) spring migration. Even more, the fact that two owls from different wintering sites summer in the same island, makes one think that this might be no coincidence.

Spring and summer movement tracks of adult female Wells and adult male Outlook in 2018. Top left: a zoom-in to King William Island, where they both settled in summer that year. (©Project SNOWstorm)

And so, this brings us to another exciting result. In the following short clip, you will see a “heatmap” of the summer settlement areas of tracked snowy owls during three consecutive years. Anything particularly noticeable? For me, it appears that every year, the breeding hotspots differ, and most owls follow this trend, as we humans do when choosing the next touristic place to visit. So how do they know this? Is it an exchange of information between different owls at places where they meet during migration? Do they perform a kind of  follow-the-leader? Did they know this location would have lemmings based on information gained in years prior? In any case, this northwest to southwest diagonal in the remote tundra likely constitutes a stronghold for summering areas, with vital habitat characteristics for this owl to reproduce; and this is of utmost concern, since research and conservation efforts could be directed to this area.

Heatmap of summer settlement areas of GPS-tracked snowy owls during three consecutive years (2016-2018). The green color goes darker in the areas where there more owls summering. N = number of owls tracked per year.

 As always, nature’s ability to surprise us appears endless. When we think we are getting to some cerebral and analytical point that leaves us more relaxed for our brains used to predictability and routine, then it strikes us again with the extraordinary, reminding us of its ever-changing power that sometimes seems to relate more to art than to science.

For my part, I will try my best to understand the intricate movements of these amazing creatures. What I am sure of, is that those poetic words of an old hobbit: “Not all those who wander are lost.”

Thank you Project SNOWstorm for your support in this new adventure of my life!

Diego Gallego García is a Spanish biologist who has devoted his research career to wildlife biology, focusing on the ecology and conservation of raptors in the Americas. His doctoral research was at National University of Comahue, Argentina, studying the movement ecology of the endangered Chaco eagle (Buteogallus coronatus). He is also a member of CECARA (Center for the Study and Conservation of Birds of Prey in Argentina).