Q. - How can I deter crows from eating the rubbery parts of my car? Last summer, I watched as crows pecked away at my sunroof sealer. I used the car's remote to honk the horn, which startled the crows. But they persisted. Eventually, it got to the point where water was entering the cabin when I went through a car wash. So I replaced the sealer – for about $400. By the time I put up a scarecrow in the fall, most of the sunroof seal was gone. I really don't know if the scarecrow will be effective during next year's nesting season. I've also cut down a nearby tree that might make it slightly less attractive for crows to land on.– Ray
A. - How do you keep a murder of crows from picking at your sunroof? Make 'em think your car has murdered a crow.
"He'll need need an effigy of a dead crow – or if he ever finds a dead one, use that," says John Marzluff, professor of wildlife science at the University of Washington. "There are people who keep a frozen dead crow in their freezer and take it out whenever crows are at their bird feeders."
If you don't have a dead crow handy, Marzluff says to get a crow decoy or one of the fake ones sold around Halloween ("but not a fake-looking one with an orange beak"). Put it on the sunroof and scatter some black chicken feathers around – the point is to get crows to associate your car with death, and spread the word.
"It's not uncommon for cars to kill birds," says Marzluff, author of Gifts of a Crow: How Perception, Emotion and Thought Allow Smart Birds to Appear like Humans. "So they'll decide that this is a dangerous car."
Other solutions probably won't work for long. Crows get used to scarecrows. And a plastic owl or a bunch of rubber snakes will probably attract more crows – crows gang up on predators.
"They'll scold a plastic owl and try to move it," says Marzluff. "But they won't associate it with your car and think, 'this car keeps producing owls'."
The Internet is full of suggestions, ranging from hanging pie plates and mylar ribbons on strings to setting up speakers to broadcast predator calls.
"Crows don't like change," says Kevin J. McGowan, a behavioural ecologist at Cornell University. "But they're smart and they get used to things, so you'd have to keep trying new stuff."
Anything that could harm a bird, like a mousetrap, is wrong, and illegal – and chemical repellents don't seem to work.
"Cayenne pepper won't work, it's a mammal thing," McGowan says. "One that gets used with birds is methyl anthranilate, from grape skins, but not with a whole lot of success."
You could keep finding ways to scare them and chase them away, but you'll have to be careful – if they get angry at you, they could give you the Tippi Hedren treatment.
"They recognize individuals," McGowan says. "So you don't want to get 'em too mad at you."
Nobody's sure why crows pick at the rubber seals around windows and tear the rubber blades off windshield wipers. Marzluff thinks that they might be trying to get into your car.
"With animals, crows pick away at the soft underbelly to get in," he says. "Maybe there's food or something in the car they're after."
Another idea is that the crows aren't after the rubber at all – males are attacking their reflections on in the glass, thinking they're other males.
"You get that a lot with cardinals and other birds, they're full of testosterone – but crows don't really do that," says McGowan. "And they pick rubber and tar off roofs too, not just windows."
McGowan thinks the rubber picking might be juvenile delinquency. And they could be teaching the trick to other, younger crows – so this could go on for years.
"Crows are pesky – they're not really adults until they're two years old, so they get into mischief," McGowan says. "The adults are serious, they have work to do."
And it doesn't seem like crows use the rubber in nests. Usually they're seen just picking the stuff out and throwing it on the ground.
"It could just be that a juvenile has discovered the seal somehow, and he likes the texture," McGowan says. "Some crows collect shiny things – we all need a hobby."
If crows have their minds set on that seal, they'll probably keep coming back. They could potentially find your car miles away.
"I've got crows chasing my car down the street because I give them peanuts," Marzluff says. "A couple of weeks ago I had crows find me in my car miles away from my house."
He says maybe feeding them might convince them to leave your sunroof alone – "quid pro crow."
"It wouldn't hurt to try a peace offering and maybe they'll move over to some other car," he says with a laugh. "Unsalted, in the shell."
I checked with the Audubon Society in the U.S. and the Royal Society for the Protection of the Birds in the UK. They both suggest using a car cover.
Marzluff's had to fight criminal crows before – a park in Washington called him in for crows ripping the rubber off windshield wipers on parked cars.
The National Park Service gave out PVC tubes for campers to stick over wipers. And Marzluff found one corvid culprit and taught it a lesson.
The trick there was aversive conditioning – to make the crow associate the rubber with something unpleasant.
"We captured it and then tagged on top of a windshield wiper," says Marzluff.
"So, he could throw pieces of rubber stripping at the crows and maybe they'll get the idea that rubber is bad."
But don't crows recognize people?
"Yeah, he should wear a mask," he says.
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