Swallows are remarkable little birds. They can be found on every continent except Antarctica, dashing and dipping through the air with rapid-moving wings.
Bank swallows, as their name suggests, breed in colonies along riverbanks, lake edges and bluffs. These two-toned white and brown birds can be spotted from below, in part by the distinctive brown band running across their necklines.
Barn swallows stand out with their cobalt blue feathers and deeply forked tails. They often fly just a few inches above the ground or water, and their cup-shaped mud nests can be found quite often on human-made structures.
These birds used to be amongst the most common of our feathered friends. But their decline in numbers has ornithologists anxious. Bank swallows in particular have faced a devastating 98 per cent population decline in the last 40 years in Canada. Both bank and barn swallows are an at-risk species (labeled as threatened under Canada’s Species at Risk Act), and barn swallows are also blue-listed in the province of B.C.
In the Columbia Valley, biologist Rachel Darvill has dedicated years to studying wetland birds up and down the Columbia River (from Canal Flats to Donald).
During a five-year intensive study of waterbirds in the Columbia wetlands, citizen scientists under Darvill’s direction observed six different species of swallows, as well as multiple nesting sites. But it was unknown just how many swallows nest in the Columbia Valley and where their nesting locations are found.
So, Darvill set out to investigate the at-risk swallow situation here, launching the Columbia Valley Swallow Project (CVSP) in April 2020.
The main goals of the CVSP are to build increased awareness for swallow species and their conservation status, coordinate volunteers to inventory and monitor swallow nests, and next year – to erect artificial nesting structures for swallows to increase habitat availability.
With the help of 69 volunteers this spring and summer, the team located 134 swallow colonies in sandy banks, with 98 confirmed to be active bank swallow colonies! The high number of bank swallow colonies in the Columbia Valley indicates that this region provides significant habitat for this species, says Darvill. Volunteers also located 17 barn swallow nest sites, including a significant colony in Brisco with at least 32 active nests. Nesting sites are of particular interest to Darvill, who explains that while individual birds may or may not return to reuse a specific nest or burrow, nesting colonies are reused by swallows year after year. Threats to nesting sites could further reduce population numbers of these at-risk birds.
“This area is critical for bank swallow populations because of the unique habitat found here,” says Darvill, noting that the vertical, glacial, clay-like banks adjacent to the Columbia Wetlands and lakes are perfect for colonies – soft enough for nest digging, but hard enough so that they don’t collapse. And the adjacent grasslands and marshy areas are prime foraging habitat for these aerial insectivores (birds that eat insects – like the swallow, whose average weight is only 10-18 grams, but can eat up to 850 insects, such as pesky mosquitoes, per day).
Darvill will soon be sending the recently compiled Columbia Valley Swallow Project data to Environment and Climate Change Canada, which assesses potential areas for bank and barn swallow critical habitat designation. She has applied for funding to launch a five-year follow-up project, which will oversee the installment and monitoring of artificial nesting structures at sites where current nests are unwanted due to health or aesthetic concerns. She also aims to restore degraded breeding sites, monitor existing colonies, and eventually plans to tag bank swallows to learn where they go during winter and to better understand movement patterns around their breeding colonies. Such information can be used to assist with biodiversity and sustainability goals as well as to inform regional planning processes.
If you want to help swallows in this region, there are numerous ways you can assist these small but important birds. Darvill suggests keeping your outside lights off at night, as exterior light pollution can strongly disrupt nocturnal migratory behaviour through disorientation. Make your yard more bird-friendly by installing nest cups or boxes and by keeping your cats away from nests and young newly fledged birds. You can also participate in volunteer projects such as the Christmas Bird Count or the swallow citizen science project with Wildsight Golden.
To learn more about this swallow project, visit Columbia Valley Swallow Project. A final report on all the successes of this year’s project will be available by the end of the year on this site.
For more information, contact:
Rachel Darvill, CVSP Program Biologist
Header image: Rachel Darvill