For the Birds Radio Program: Northern Shrike
The butcherbird takes more little birds than some people can stomach watching, but some birds manage to protect themselves.
(Recording of a Northern Shrike)
A couple of weeks ago some diners at the Quarry Inn in Port Wing, Wisconsin, looked up in horror at the window bird feeder to see a shrike plunge in and grab a Black-capped Chickadee. If that wasn’t bad manners enough, the butcherbird proceeded to devour its tiny morsel right in front of them. Finally a lady tapped on the window and the shrike flew off to eat its meal where it presumably couldn’t offend anyone.
Shrikes are songbirds with long tails and gray, black, and white plumage similar to a mockingbird’s. There are two species in North America. The Loggerhead or migrant Shrike eats mostly insects–grasshoppers, dragonflies, and large beetles. These birds are easily seen throughout the year down in the sunbelt—they are easy to see perched on wires on a drive through Florida or Texas in winter. They used to be fairly common in Wisconsin and Minnesota in summer, but their numbers have fallen dangerously in the past few decades. Northern Shrikes also eat insects, but they’re more dependent on birds and mice for survival. They spend their summers far north of here, at the very limits of the tree line in Canada and Alaska. In winter they don’t generally sit on exposed perches for long—small birds recognize danger and light out for the territory the moment a shrike enters the scene. Northern Shrikes survive by surprising their prey, and their appearance at feeders is always as much a shock to the people watching as to the birds.
Because shrikes are songbirds, they don’t have the killer feet, called talons, of hawks and owls. They kill with their hooked beak, and use their feet simply to hold the food down as they eat it. In this habit they show their relationship to jays, crows, and chickadees, which also use their feet to hold a meal in place. A shrike weighs only about 2 1/2 ounces, so it can hardly carry birds much larger than a House Sparrow—it often must eat part of its prey before carrying it off. Shrikes have been known to kill birds as large as Blue Jays, but usually go for much smaller prey. They take a few chickadees, but stomach content analyses show they eat mostly birds of open areas, especially House Sparrows. Even when food is abundant, they miss far more often than they actually succeed in bagging their prey.
In 1936, William Brewster watched a hungry Northern Shrike in search of a meal. He wrote, “When I first saw him, he was in hot pursuit of one of the Brown Creepers and both birds were about over the middle of the river and scarce a yard apart. The Creeper made straight for the big elm which stands at the eastern edge of the bridge. When he reached it, the Shrike’s bill was within six inches of his tail, but he nevertheless escaped; for an instant after the two birds doubled around behind the trunk the Shrike rose to the topmost spray of the elm, where he sat for a minute or more, gazing intently downward, evidently watching for the Creeper. The latter, no doubt, had flattened himself against the bark after the usual practice of his kind when badly frightened and he had the nerve and good sense to remain perfectly still for at least ten minutes. My eyes were no better than the Shrike’s, for it was in vain that I scanned the trunk over and over with the greatest care. Feeling sure, however, that the Creeper was really there, I waited patiently until at the end of the period just named he began running up the trunk, starting at the very point where I had seem him disappear. It was one of the prettiest demonstrations of the effectiveness of protective coloration that I have ever witnessed.”
(Recording of a Northern Shrike)
That was William Brewster, this is Laura Erickson, and this program has been “For the Birds.”