Every year my spirit alternatively soars and then sinks as one to three billion birds migrate to Canada's boreal region to breed and then depart with two billion young for their southern wintering grounds. Each year I wonder, who will survive the journey south and who will come back next spring?
Spring Tree Swallows (Tachycineta bicolor) in southern Yukon. While not the first songbird to arrive in the spring, it is the return of swallows dancing in the sky that most lifts my spirits after a long, northern winter. Photo © Jukka Jantunen
The boreal region is a broad swath of forest, rivers, lakes, and wetlands blanketing 55 percent of Canada. It stretches through Alaska to the coast of Newfoundland and from the shores of Lake Superior and the North Saskatchewan River to the edge of the Arctic plains.
Three hundred bird species breed in Canada's boreal region. For a third of these species, the area supports more than 50 percent of their entire breeding range. Most of our boreal birds spend more time farther south in North, Central, and South America. But without breeding habitat, these species won't survive. Canada has a global responsibility to monitor and protect these birds.
I live in the Yukon, where winter stretches from October to April. While the arrival of swans is the first real sign of spring, it is the return of swallows that lifts my spirit and reminds me that the forests will once again swell with birdsong. There is a comfort in the cycle of the seasons, in the surety that a wave of life and renewal will once again surround us.
The tiny 12 gram Blackpoll Warbler (Setophaga striata) breeds in boreal treed wetlands and migrates farther than any other North American warbler - including a 3-day, 3,000-km non-stop flight over the western Atlantic Ocean. Photos © Jukka Jantunen.
For me, the grounding feeling of spring has never been as profound as it is living in Canada's northern boreal. So it worries me that, on average, Canada's breeding bird populations have declined by 12 percent since 1970.
Focused management and conservation have increased populations of waterfowl, colonial seabirds, and raptors, but several songbird groups have significantly declined. Aerial insectivores, birds like swallows that catch insects in flight, have declined by more than 60 percent since 1970 - the greatest decline of any bird group in Canada.
As is true for most birds, there are likely multiple causes for declines in aerial insectivores. Habitat loss is the single greatest threat to birds. Canada's southern boreal has experienced extensive conversion of natural habitats for forestry, agriculture, and industrial development.
Tundra (Cygnus columbianus) and Trumpeter Swans (C. buccinators) are the first migratory birds to arrive in southern Yukon in spring. Photo © Jukka Jantunen.
On their southward journey, boreal songbirds must navigate transformed landscapes to find patches of natural habitat for resting and refueling. They risk death from cats and collisions with human structures. The risks to survival don't end when they arrive at their southern homes. Resource development is destroying natural habitats and toxic pesticides are widely used.
Canada's northern boreal remains one of the last wild places on Earth. For songbirds, it's also one of the last unknowns. Across North America, the annual Breeding Bird Survey monitors birds to detect and quantify changes in population size. Unfortunately, for the monitoring of Canada's boreal songbirds the southern 49 percent of the boreal region receives 89 percent of the survey effort.
This leaves a huge gap in monitoring across our northern boreal at the same time as southern boreal bird surveys indicate significant declines in many species. Thirty percent of Canada's bird species are insufficiently monitored to reliably determine if their population is threatened; the majority are boreal songbirds.
For much of the boreal breeding range of the Blackpoll Warbler (left) there is little to no long-term population data. Right: Breeding Bird Survey (BBS) relative abundance map for Blackpoll Warbler, 1987-2006; Legend: average birds/route/year; white = species not detected; grey = no BBS data). Click for sources: left and right.
Without sufficient monitoring in the north, we don't know if declines in Rusty Blackbirds (Euphagus carolinus), Blackpoll Warblers (Setophaga striata), and other boreal songbirds are limited to southern boreal breeding areas or representative of broader, range-wide population declines.
In the Yukon, we work with other scientists and biologists to fill gaps in knowledge about boreal songbirds: where they breed, what habitat they prefer, and how many there are. But the only way to meet Canada's global responsibility for protecting boreal birds is substantial investment in a national, coordinated strategy of long-term monitoring across our northern boreal region.
Without a serious commitment to monitor populations of northern boreal songbirds, my fear is that one spring, after another seemingly endless winter, my heart will not be lifted by the dancing flight of swallows or the comforting chorus of bird songs.
The Myrtle form of the Yellow-rumped Warbler (Setophaga coronata) is a ubiquitous breeder across Canada's boreal forest, but it's commonness doesn't diminish my joy of it being the first spring warbler in southern Yukon. Photo © Jukka Jantunen.
As a conservation scientist I know this is unlikely. Despite significant bird declines, few, if any, species will become extinct in my lifetime. But on a personal level, it is the possibility of a future with fewer spring swallows and singing warblers that worries me. I am driven by the fear that our northern boreal birds will decline in abundance without our knowing.
Here in the North, the swallows and warblers have already started their journey south. I anticipate another long, anxious winter waiting for our three billion boreal wonders to return.
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