Ravens in Winter: A Zoological Detective Story

In 1984 Heinrich, professor of zoology at the University of Vermont, determined to find out why ravens call to each other when they discover food, a rare example of sharing in the wild. For the next four years he spent winter weekends observing these birds at a remote site in Maine, braving fierce weather, lugging enormous amounts of bait to lure ravens to his study area and sleeping in a cabin where temperatures often plunged below zero at night. The story related here, which is constructed from his field notes, moves slowly; we learn a good deal about scientific methods and a lot about patience. Overall, however, the book is suspenseful and exciting. The author follows a series of clues, some going nowhere, and others finally leading to the solution to this puzzle of animal behavior. The climactic moment comes after Heinrich, having trapped and banded more than 40 ravens, is able to discover, first, that only certain juvenile birds make the calls, and then, why they do so. Illustrations not seen by PW. (Sept.)