The power behind scarecrows

Dear Matthew Alice: Why do scarecrows scare crows? — Michelle, Sarah, and Corrie, East San Diego

When the first humanoid stuck the first seed in the ground and waited for it to sprout, somewhere in the trees was a flock of birds that knew a good thing when they saw it, just waiting for Og to go back into the cave for a beer. The first scarecrow was undoubtedly Og himself, running through the garden, yelling and flapping his hat. When he got sick of that routine, maybe he took an old loincloth, stuffed it full of straw, and stuck it in the garden, figuring the dumb birds would be fooled. They weren’t. They still aren’t. Scarecrows don’t scare crows, as any gardener can tell you.

If the traditional straw man on a stick actually worked, we wouldn’t have such a colorful history of experimentation with bird-chasing techniques. Illustrations from medieval England show farmers leading their plow horses through the fields, waving poles at marauding crows. By the mid -1700s, British farmers had progressed to psychological warfare — hanging dead crows from sticks, throwing crow carcasses in the air, or covering the ground with dismembered birds. In fact, by the 18th Century, the scientific flaw in the scarecrow plan was fairly well-known. Birds are wary of new objects in their territory, but they’ll rapidly get used to almost anything. A fake man on a stick makes a handy perch once they learn not to fear it.

For a while, farmers tried using birds’ natural enemies — trained hawks and falcons — but that could have the opposite effect. Small birds often flock together to attack larger ones, so instead of a few birds, some farmer ended up with mobs of them. The level of desperation has risen in modern times, with butane-fueled cannons, propane detonator noise bombs, police sirens, recordings of bird distress calls, hawk-shaped kites, and mylar balloons. The birds just snicker and keep eating.

Farmers in Southern California often hire people to roam their fields and harass the birds (pajareros, in farmworker lingo). Some put their bird-chasers on bicycles with bells and horns. They have even tried aerial combat — chasing birds with radio-controlled model planes, with some temporary success as long as the birds are flying. If they’re on the ground eating, the birds couldn’t care less. One interesting news account describes a farmhand shooting something called a 15mm Moog Screamer Siren rocket into a field of birds eating strawberries. They moved about 50 yards down the patch and resumed their lunch. (Strawberry farmers have lost as much as 30 percent of their crops to birds.) The beleaguered British have tried a pop-up inflatable scarecrow that sounds a siren, then deflates and falls over. A scarecrow researcher in Connecticut developed a product he calls Crow-killer Scare-away, a battery-powered mechanical owl with a stuffed crow in its talons that flaps its wings. It seems to work if you move the thing around your garden every day or so. Otherwise, the birds get used to it, too, and ignore it.

The ultimate scarecrow may be something Mississippi catfish farmers have used to chase away cormorants that eat up their profits. The “air crow” is reported to deploy strobe lights and inflatable plastic arms, accompanied by honking horns, recorded human screams, shotguns firing, and the shrieking of birds played at a volume of 130 decibels. The cormorants are still there, but I’ll bet several neighbors have moved. The person who develops a foolproof scarecrow will make a fortune.