A pair of loggerhead shrikes nested this year at Fermilab near Batavia in Kane County. Vicky Byre of the Chicago Academy of Sciences first saw them in early May. By May 18 there were eggs in their nest, and on June 8 five young birds were fledged.
Their principal weapon is their beak, which is heavy and powerful and supported by large muscles that give loggerheads their big-headed, thick-necked look. They peck hard at anything they are trying to kill, but they kill prey mainly by biting. They have a toothlike structure on the upper beak that fits into a notch on the lower beak to produce an effective biting machine. They go for the back of the neck, biting rapidly until they snap the spines of their victims. Falcons have similar structures on their beaks and use them in much the same way.
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Because they lack the powerful feet and curved talons of falcons, hawks, owls, and eagles, shrikes’ hunting–and eating–strategies are much different from these other birds’. The other raptorial birds capture their prey with their feet and in many cases kill with their sharp talons. The shrike’s weak feet aren’t up to heavy work of that sort, though some loggerheads have been known to carry dead prey in their feet.
Hawks and owls use their powerful feet to hold their prey while they tear off bite-size pieces with their beaks. The shrikes have developed another method. They either wedge their catch in the forks of tree branches or, more commonly, impale it on thorns and then pick at it. Where shrikes are living, you may come across a larder in a thorny bush: a collection of insects, birds, mice, and small reptiles, dead, impaled, and awaiting eating. As many as 15 small snakes–along with various insects–have been found in such larders. These larders give shrikes one of their widespread common names: butcher birds.
In the forest preserves of northeastern Illinois, there are thousands of acres of weedy old fields dotted with buckthorn bushes. So why don’t we see shrikes nesting there?
However, according to Dr. Temple, loggerheads are doing quite well from the Dakotas west to California. The birds in those populations winter in Texas, Oklahoma, New Mexico, and other inland locations that have not been as drastically altered as the Gulf Coast.
