Semantic Value of French and American Crow Calls Tested Reciprocally

Abstract

In France, we have studied the reactions of certain crows to the recorded assembly call and alarm call of the American eastern crow, and the reactions of certain gulls to the recorded food-finding call and alarm call of the American herring gull. For the French gull L. argentatus, the same species as the American form, neither of the calls provoked observable reactions when broadcast from distances of 50 to 1200 m. In the United States the food-finding call is strikingly attractive and the alarm call repellent. With roosting French crows, the alarm call of the American species had no effect. The assembly call, in 52 tests near Paris, provoked several reactions similar to the reactions evoked in American crows by this call. In the United States a few recorded calls of French crows were tested by broadcasting to the Eastern Crow, including cries of nestling C. frugilegus and distress calls of adult C. monedula and C. corone. The former elicited no observable reactions in Maine during the summer, but proved slightly attractive in Pennsylvania during the winter; the distress calls produced no observable reactions. Unfortunately, no attractive calls (such as the assembly call) of French crows have been received to date for testing in the United States. These preliminary experiments have some interesting implications so far as ideas of animal pseudo-language are concerned. It is curious that calls of the same gull species may not have generalized meaning; the alarm or distress calls of the crows, likewise, seem to lack general significance. On the other hand, the assembly call of the American eastern crow releases in three different species of French crows the same reaction as in the American species, thus apparently having a similar semantic value for all. The reactions of American crows to the cries of French nestlings suggest a generalized semantic value with some specific overtones.