A backyard bird feeder isn’t visited just by birds looking for seed. Sometimes a predator will pay a visit, and its arrival will cause the finches, chickadees and other feeding birds to scatter. A cat will cause birds to fly away from the ground, often to the tops of nearby shrubs and trees. If the birds fly instead deep into the tangle of branches, they are avoiding a predator from above, possibly a shrike.
Shrikes are songbirds like many of the birds attracted to feeders, but unlike those birds, they are fierce hunters. Shrikes attack and kill a variety of prey: other birds, mice, lizards, insects; at times even tackling prey larger than themselves (a shrike is about the size of a robin). They kill using their hooked beak; their feet are too weak to kill with grasping talons like hawks and owls. Their feet, in fact, are what make them “songbirds” – biologists define songbirds (also called perching birds or passerines) not by their singing ability but by their feet that have three toes facing forward and one backward, making it easy to grasp a branch. One could think of shrikes as songbirds that “want to be hawks;” their behavior is very hawk-like.
Shrikes hunt by sitting on an exposed perch, patiently watching for prey. The attack is swift, the shrike launching itself directly at its intended target, often flying low to avoid detection, then pouncing on its prey on the ground. Shrikes kill by pounding their sharp, hooked beak into the back of their prey’s head, eventually severing the spinal cord – a method like that used by falcons. Drive along a country road and you might see solitary shrikes sitting on hunting perches, often at the edge of fields. In the winter, some shrikes come into town to hunt at bird feeders.
A shrike might not eat its prey immediately. Instead, the bird carries its prey to a “larder” where it will store food items impaled on barb wire, thorns, broken twigs, or simply wedged into the fork of two branches. This gruesome practice has earned shrikes the name “butcher bird.” Male shrikes may use a well-stocked larder to attract females at nesting time.
Shrikes are grey birds with dark wings that have white patches, and they have a distinctive black band at the side of the head through the eye. Northern shrikes visit Minnesota in the winter, returning to northern Canada to nest in the summer. Loggerhead shrikes arrive in Minnesota in the summer from their winter range to the south. Loggerhead shrikes are currently listed as a threatened species in Minnesota; fewer now nest in the state, mostly in southern and western Minnesota. It is northern shrikes that make a dramatic visit to a backyard feeder in winter. They are paler, slightly larger than loggerheads, and their dark eye band is narrower, not crossing over the bill at the front of the head.
Northern shrikes are not common, so sighting one could be difficult. In February, you might first find evidence of shrike predation – dead sparrows or mice skewered on thorns or barbed wire – before spotting a shrike hunting nearby.January 31, 2013
Bill Allen is a freelance writer from St. Louis Park, Minnesota.