Animals have many ways of behaving that have no meaning except through the effect they have on other individuals. These strange calls, dances, and postures are called display. For many years I have spent many peaceful hours watching the birds display on the pond at the McDonogh School Bird Refuge. At all times, but especially in the fall and winter, this has proved a fascinating study. All of us are familiar with threat display. We frequently see this display in domestic animals, such as the dog and cat, and its effectiveness is also known to us as we respond to the growling and bristling of the dog or the arching and spitting of the cat. Such display signals the animal's readiness for combat, but it is most interesting that in many cases the display serves to avoid conflict. In fact, in many animals such as the birds, the display has become so highly developed that it has come to take the place of physical encounters between members of the same kind almost entirely. Many animals have developed elaborate structures for threat display as well as elaborate postures and call notes. The effectiveness of such additional structures in the frilled lizard has been described recently by C. M. Bogert in Natural History, February, 1957. Here the gaping red mouth and the sudden opening of the frill on his neck are as effective as my grandmother's umbrella. This gentlewoman frequently used this weapon in the same fashion to intimidate Sahara, an overly friendly cow of strictly honorable intentions. Threat display is used in the defense of territory, and the possession of such rights is the first thing one must do to secure a mate. David E. Davis has studied the starling for many years and has told me that in the starling, for example, it is the birds that have no land-rights that form the familiar wandering bands, whereas the males possessing territory meanwhile may have a succession of mates. Another very familiar form of display is distraction display. It is aptly named. The parent bird seems to be trying to distract the attention of the enemy. Actually she is probably almost paralyzed with fright. At the same time she has a strong inclination to stay on the nest and with the young. This tendency tostay on the nest and to defend the young can be observed to increase all during incubation and after the young hatch. In other words, distraction display is thought to represent a conflict between the impulse to run away and the contrasting inclination to stay and attack. I have seen distraction display in nesting Shovellors. The bird will flounder about, meanwhile calling pitifully. If followed she will manage to flutter and crawl away a bit and then again be seized with helplessness. Such birds have been observed to lead foxes and the like away from the nest. Closely related to injury-feigning display is death-feigning display, playing possum, and freezing. This is found in many animals. It is probably most highly developed in defenseless creatures such as birds and insects. Here it is often coupled with protective coloration and protective resemblance. Tinbergen describes experiments where dead-stick caterpillars and feeding Blue-Jays were used, and the importance of freezing was proved. The fact that the caterpillars looked like sticks was only effective if they also behaved like one. Scientific American, October, 1957. The most conspicuous form of display is commonly called courtship display. In many species other forms of display are connected and are a part of whole series connected with reproduction (epigamic display). Here is where the most elaborate structures, vocalizations, coloration, and dances have appeared, from the song of birds and the strutting of a peacock to the waving of his giant claw by a male fiddler crab. The Wood Duck represents a species which possesses an elab-
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Apr 1, 1998
A D Griffiths + 2
Open Access