Derek Matthews, chair of the Vancouver Avian Research Centre, says that populations of barn and bank swallows in particular have fallen by up to 98 per cent in Greater Vancouver since 1970 and the decline seems to be speeding up.
Matthews characterized the situation as “desperate, really desperate,” and says his research team has noticed a particularly fierce drop off in the last three to five years.
Similar patterns are emerging for other species too, like tree, cliff and northern rough-winged swallows, according to data from the North American Breeding Bird survey.
According to Matthews, a combination of factors has contributed to declines in swallow populations.
Losses of natural and artificial nesting habitat, widespread use of pesticides on agricultural land and an increase in light pollution throughout Metro Vancouver have all played a role.
Swallows make clever use of barns, garages and other structures that provide shelter similar to their preferred wild nesting habitat.
Today barns and similar artificial nesting sites, are being made out of materials like steel, which is better at keeping swallows out and is less than ideal for their needs, says Matthews.
There has also been a corresponding reduction in populations of many flying insects, a primary food source for swallows. Pesticide use and light pollution are driving insects away from populated areas like Vancouver, he says.
Matthews thinks that a “massive research effort should be considered” to understand how swallows might thrive once again in Metro Vancouver.
Bird studies take patience and manpower, though. In the meantime, there are simple things residents can do to help swallows out.
“Put up swallow ledges, open barns, garages, carports and other important nesting sites,” Matthews says.
“Even a simple wooden ledge” can provide enough suitable habitat for swallows to breed and rear their young successfully.
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