By Rex Graham
The Eastern Gray Squirrel, that familiar, frustratingly funny inhabitant of the backyards and forests of the East and Midwest U.S., has become an urban seed thief and gnawing ecological threat in Europe.
Millions of North American bird lovers appreciate what increasing numbers of Europeans must be going through: a daily backyard battle of wits with a foe that routinely comes up with clever new ways to raid birdfeeders.
Hundreds of people have posted YouTube videos of rodent antics at their squirrel-proof feeders. Soundtracts often include laughter and incredulous comments. Expensive caged feeder don’t deter intrepid squirrels. If one path is blocked they will leap from nearby limbs to reach sunflower seeds intended for Cardinals, woodpeckers and chickadees.
More than 50 million Americans own birdfeeders and many resort to an astonishing array of anti-squirrel techniques and technologies. Some resort to spraying the seed poachers with garden hoses or coating the poles holding feeders with Teflon spray or vegetable fat laced with crushed red pepper.
Some simply give up and feed squirrels and birds.
U.S. export: seed-thieving gray squirrels
The United States’ most precocious backyard pest was introduced to Europe by the early-2000s. The gray squirrel transplants are now invading attics and destructively de-barking trees in England, and bullying the smaller local red squirrels in Ireland and Italy.
By mid-century, few European backyards will be safe.
Surveys have found that gray squirrels are the most spotted wildlife species in U.K. gardens. Where they find bird feeders, Britons soon discover what Americans know all too well: squirrels take over.
Embracing randomness and surprise
“Birds are pretty; their songs are pretty; their colors make them look like flying rainbows,” writes Bill Adler in the third edition of Outwitting Squirrels: 101 Cunning Stratagems to Reduce Dramatically the Egregious Misappropriation of Seed from Your Birdfeeder by Squirrels. “But the squirrels make it fun. The squirrels bring out the unexpected. The squirrels add randomness and surprise.”
Maybe Europeans place a lower value on randomness and surprise than Adler. One surprise few have been treated to is a view of their own native European Red Squirrel. They’ve nearly vanished from urban areas.
Since the introduced gray Squirrel is a non-native species, biologists in Europe fear that backyard birds there are not prepared to compete at the birdfeeder. A new study of birds’ avoidance of gray Squirrels (in this case, fake models of squirrels) indicates that they are extremely fearful of squirrels.
Urban birds may suffer
“Birds typically avoid feeders like the plague when gray squirrels are using them,” said Colin Bonnington, a researcher at the University of Sheffield in the U.K., and a leading European expert on the impact of squirrels on birds. “As gray Squirrels move into more urban areas throughout Europe, they may clear out the limited number of feeders in some areas, and urban birds may suffer.”
In a paper published in the January 2014 issue of Ibis, the international journal of avian science,Bonnington reported that models of gray squirrels in Sheffield, England, prompted all but one species of bird, the European Robin, to fly away from backyard feeders.
“To be fair, even the robins showed anxious behavior when the squirrel models were on the same feeder and didn’t stick around very long,” Bonnington said.
Squirrels don’t hibernate. In winter, when many birds are dependent on bird feeders, “interference competition” could result in starvation of many birds.
Squirrel-proof feeders are regarded as an important technology to benefit European birds. However, Bonnington himself has witnessed the uncanny abilities of squirrels to get what they want.
“They seem to get around most things if they have their hearts set on the contents,” said Bonnington. “Caged feeders are certain better than normal feeders for keeping squirrels at bay — sort of. They are also less likely to break metal caged feeders, but they will bite right through plastic feeders like there’s no tomorrow. “
Italian researchers have taken a hardline attitude toward the American squirrel.
In central Italian town of Perugia, the new squirrels are seen as a threat to a local red squirrel subspecies. “The grey squirrel population around Perugia should be eradicated,” wrote an international team of scientists in a paper published March 2014 in Biological Invasions.
Killed squirrels could be replaced by individuals that escape from pet stores, or be intentionally released. Animal-rights activists could thwart any plan to cull squirrels.
In Berlin, squirrel bridges have been built by squirrel fanciers to make it easier for them and pine martens to move from neighborhood to neighborhood on the overhead bridges without the need to run across dangerous streets.
“We have more wild animals in the city than in nature,” Ursula Bauer, a resident of Aktion Tier, said in an online news story. “They are living together with us and we have to deal with it. The traffic is very dangerous for them – for the hedgehogs, for the birds, and of course for the squirrels.”
Biologists in Ireland were surprised when the native population of red squirrels suddenly rebounded due to a larger, easier-to-catch food source: the American gray squirrel. Scientists discovered that the European Pine Marten preferred the grays to the smaller, harder-to-catch reds.