Researchers at Trinity Western University are experimenting with a natural way to deal with the overpopulation of European starlings by trying to boost the population of their predators.
Since their introduction to North America more than a century ago, starlings have thrived on this continent, with estimates of their numbers ranging from 200 million to two billion. These invasive, speckled birds feed on insects and berries – and appear to have a particular fondness for the sweet blueberry crops of British Columbia’s Fraser Valley.
There are approximately 12,000 acres of blueberries under cultivation in B.C., but when a mass of starlings come calling, they can quickly ruin a third of the crop, says Karen Steensma, a biology professor and co-director of the environmental studies program at TWU.
Blueberry growers have tried a variety of methods to scare the pests away, including hanging nets and playing loud noises, but the birds quickly catch on.
Although starlings have few natural predators in the area, they are petrified of kestrels, a small type of falcon that can snatch a starling in mid-air. Professor Steensma says starlings are so scared of this predator that they’ll flee even at the sight of a kestrel shadow. In areas where kestrels are present, starlings are scarce.
However, urbanization, large-scale farming and pesticide use have decreased kestrel nesting habitat and food sources. With this in mind, Professor Steensma is leading the Kestrel Nest Project, which seeks to increase the kestrel population in hopes of keeping the starlings at bay.
Funding for this pilot project comes from the B.C. Ministry of Agriculture, the B.C. Blueberry Council and some American sources (the province’s starling woes are shared by nearby Washington State).
Those working on the project take in orphaned kestrels and release them into the wild when they’re ready. They also deposit nest boxes around farm fields to encourage kestrel nesting. So far, they’ve deposited 50 nest boxes and are planning to put out another 40 before the kestrel mating season begins in February. The team has released two orphaned kestrels, a female and male, both of which Professor Steensma believes are prospering in the wild. She’s hoping to release at least 10 more kestrels this year.
Oddly enough, starlings were recently declared an endangered species in England, their homeland, which Professor Steensma attributes to urbanization and a changing farming landscape.
Starlings became permanently established in North America in 1890, when several dozen of the birds were released in New York’s Central Park. The stunt was dreamed up by an Englishman named Eugene Scheifflin, who thought it would be romantic to release all the birds mentioned in the works of Shakespeare into North America.