The design of this issue pointed out the need for protecting wildlife, and was the first in an annual series. The wood duck is an example of a "perching duck," which rests on tree branches and nests in tree holes. Ducks are gregarious and exhibit social behaviors such as greeting and threatening calls, and takeoff signals that integrate group flight patterns. Because of imprinting, a form of learning, young ducklings follow the first moving object they see after hatching and later prefer it to other social objects. Normally, the mother fills that role.