If you live in rural Manitoba, you are probably familiar with the various types of swallows that spend their summers here: the dark-green and white tree swallow which nests in boxes or cavities; cliff swallows which nest in colonies under bridges or occasionally on barns; the smaller light- and dark-grey bank swallow which tunnels into riverbanks; and the navy and beige/rust-coloured barn swallow, with its deeply forked tail.
But have you noticed that swallows in general are becoming less common? This is particularly true of the bank swallow and the barn swallow, which nests under barn eves, on rafters in barn lofts or in open garages or sheds. Barn swallows have long been friends of farmers, helping to keep down mosquitoes and other insects, but there are far fewer now than in the past. The Bird Canada website lists the barn swallow under the ‘threatened’ category (just after ‘endangered’), while the Manitoba Breeding Bird Atlas site lists both barn and bank swallows as ‘species at risk.’
One reason for the decrease is probably due to fewer nesting spots, especially for barn swallows. The old-fashioned wooden barn with wide-open doors and high haylofts is virtually gone, while wooden granaries are increasingly rare.
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One place we have noticed barn swallow nests is in shelters built in park campgrounds. Last spring, when my husband and I were camped at a provincial park, we saw that a pair of barn swallows had started a nest on the side of our fifth-wheel camper. Since we planned to stay only a couple of days we discouraged this, and eventually the birds moved off to begin a nest under the bathroom roof.
Tree swallows have not been affected so much by decreased nesting sites. These birds prefer raising their young in nest boxes or cavities, and the availability of these has actually increased because of efforts to save another bird, the bluebird, due to conservation work by bluebird societies which establish nest box lines.
The side-effect is that tree swallows have more nest sites, and since they are more aggressive they may usurp some boxes intended for bluebirds. Because of that, birders usually place two houses close together, hoping that each species will choose one.
Tree swallows seem to have adapted well to this and hopefully barn swallows will adapt to changing conditions in rural areas too. Author of The Bluebird Effect, Julie Zickefoose, tells how barn swallows have adapted in towns and cities. They get into warehouses and big-box stores by hovering in front of the motion-activated electric eye that opens and closes the glass doors, thus allowing them in to build and care for nests. If birds can adapt in this way, they should be able to adapt to changes in the rural environment.
However, the mortality rate among swallows with nests is high. Last year, Friends of the Bluebirds, based in Brandon reported 217 dead baby tree swallows in 60 nests. Members suspect this may be due to increased use of pesticides in nearby fields. If most insects were killed off, there might not be enough for the birds to eat, causing the young swallows to starve to death.
If you see swallows this spring, be sure to welcome them back. They have had a long flight — tree swallows from southern U.S. and Central America, and barn swallows sometimes all the way from Argentina. If you have an old wooden barn or shed that the barn swallows could use for nesting, perhaps you could leave it standing. If they begin a nest on your house or garage — maybe above a light fixture, over top of your car, or some other unsuitable place (from your point of view) — consider tolerating the inconvenience for a month or two. These feathered friends need our help if they are going to survive.