By: Hilary Cooke

It’s our fourth week monitoring spring migration in Yukon’s Tintina Trench. Since mid-April we’ve been travelling between Watson Lake in southeast Yukon to Faro in the heart of the Trench, tracking the migration of swans, geese, ducks, and cranes.

Sandhill cranes and the smaller snow geese migrating through Yukon’s Tintina Trench in spring. Credit Hilary Cooke

It’s been a slow spring – by early May the lakes were still frozen, the snow was still deep in the bush, and while some swans, geese, and ducks were starting to move through, the numbers were much lower than in previous years. Some sandhill cranes had also started their roughly two-week migration along the Trench, making their way from staging areas in southern Alberta and Saskatchewan to breeding areas in western Alaska and Siberia. But early spring species, such as American robins and yellow-rumped warblers, had yet to arrive. 

That all changed on May 8^th. We woke on that day to grey skies, low clouds, rain and wind. By mid-morning it was clear the weather was forcing migrating birds of all kinds – geese, swans, waterfowl, shorebirds, raptors, and songbirds – down from higher altitudes into the valley bottoms of the Tintina Trench.

Over the course of the day we observed hundreds of thousands of birds from 50 species – this after weeks of seeing only a few individuals from 10 species or fewer each day. Thousands of sandhill cranes passed in large flocks just above the river valley. Several hundred settled on the edge of the river alongside swans and geese to wait out the inclement weather. Greater white-fronted geese, commonly called specklebellies, passed by in the hundreds all day. Flocks of 20 or more Wilson’s snipe, lesser yellowlegs, and solitary sandpipers were common.

 After a slow spring and several weeks of observing few bird species migrating at low numbers, a single day in the heart of Yukon’s Tintina Trench brought a migratory spectacle of all types of birds, including large numbers of shorebirds, such as the lesser yellowlegs (left) and solitary sandpiper (right). Credit: John Meikle.

While a V of geese passing overhead or large numbers of shorebirds gathering on lakeshores and coastlines may be a familiar sign of migration for many Canadians, the migration of small songbirds, such as robins, warblers, blackbirds, sparrows, and swallows, happens largely at night and out of sight. But on this day, these little birds streamed by, passing low overhead with some touching down momentarily on the ground or in shrubs and others skimming low over the small trees and shrubs -- and us! 

  After a long delay this spring, Wilson’s (left) and yellow-rumped warblers (right) appeared suddenly on May 7^th, migrating in very large numbers, possibly tens of thousands, along the valley of Yukon’s Tintina Trench. Photo credits: Jukka Jantunen

We could easily count 100 individuals in a minute while standing in a single location. Standing on a bluff overlooking the river we were engulfed in waves of migrating songbirds. Some songbirds moved singly or in small loose groups, whereas others, such as Lapland longspurs, formed flocks of a hundred or more. Spring season firsts (the species detected for the first time this spring) included hermit thrush, mountain bluebirds, rusty blackbirds, savannah and fox sparrows, and orange-crowned, Wilson’s and yellow warblers.<data-blogger-escaped-o:p></data-blogger-escaped-o:p>

In 20 years of doing bird research, I have never experienced anything remotely like this. I’ve waited a couple of days to try to put the experience into words that might adequately capture the emotion, awe, and wonder of that day. I took fewer pictures and video than usual, perhaps subconsciously realizing that neither would be sufficient to share the experience. Although every day in the field is like living the nature programs I watched as a kid, this day was a migration phenomenon on the scale of the more spectacular events captured in recent nature documentaries

  Pictures are inadequate to capture a migration phenomenon of the scale we experienced at Faro, Yukon on May 7^th, 2018. In one moment, a single snapshot can only capture a small flock of Wilson’s snipe (left) or a mixed flock of waterfowl (right). These still monochromatic images neglect the immersive experience of the sight and sound of tens of thousands of migrating songbirds, shorebirds, waterfowl, cranes, and raptors over the course of a day.

Visualize your first experience seeing a wild animal, perhaps a fox or bear or moose, and the initial leap of excitement. Then imagine that happening all around you – moose, caribou, swans, eagles, bison, wolves, herons, fox, hawks, owls all at once; here, there, and above; and then the scene shifts, with more species and new species moving into and out of your line of sight again and again.

We stood in the rain and wind, cameras and binoculars grasped ready under coats, narrating our experience with a running commentary of everything we were seeing and hearing: the cranes are taking off – look, it’s about 20 Wilson’s snipe – what was that, an orange-crowned warbler – soo many robins, they just keep coming – I hear tundra swans – oh, there’s another eagle – whoa, that was a huge flock of longspurs…

And then, just standing – silenced by the spectacle. No commentary. Just the occasional click of a camera as we stood watching, listening, immersing.

Evening came, and the sky cleared. We settled on the deck of our B&B, watching the robins, sparrows, longspurs, and pipits looking for food on the lawns and field beside us as we counted the cranes until darkness settled.

The next day the sky was still clear. And then the cranes came. They flooded the sky of the Tintina Trench from morning until night. Alternating three-hour watches over the next 16 hours, we counted 98,985 cranes. Sandhill cranes are a large, long-legged and long-necked bird with a wingspan of two metres and a raspy, rolling call that I’ve heard described as prehistoric. Stretched wing-tip to wing-tip, 100,000 cranes would extend 200 kilometres or two-thirds the length of Lake Ontario.

On May 8^th large flocks of sandhill cranes streamed by in the thousands for more than 16 hours, filling the valley of the Tintina Trench at Faro, Yukon with their raspy, rolling call. By the end of the day we had counted 100,000. Credit Hilary Cooke

The boreal region of North America is not generally considered a biodiversity hotspot. That term is reserved for tropical places packed with high diversity of plants and animals. The boreal, rather, has been described as a biodiversity coldspot – not rich in species, but worthy of conservation attention because of large, wild landscapes with intact wildlife populations. Yet for a brief moment in May, a small section of Yukon’s Tintina Trench became a biodiversity hotspot for a day. I wonder where else and how often this sudden swell of diversity and abundance occurs across Canada’s north. What other biodiversity hotspots emerge and subside through the natural flow and cycles of our boreal ecosystems?

When I share stories from the field, I often report the population status of the birds we are studying, outline the threats they experience during migration, and describe our efforts to identify and protect their important migratory stopovers.

But this time, I only wanted to savour -- and share -- the story of this amazing spectacle, and the wonder and joy of being immersed in the phenomenal migratory journey of billions of birds each spring.