Factors influencing distress calling in chicks, with special reference to temperature changes and social isolation

Abstract

1. 1. Chicks placed in a strange pen give distress calls at a higher rate if the temperature of the test pen is low than if it is near body temperature. 2. 2. The rate of distress calling of socially reared chicks increases with age at 110 °F., significantly so after the third day. At 60 °F. there is no such increase, presumably because it is near maximal already. 3. 3. Chicks tested daily at the lower temperature call more than chicks without previous experience of the test situation, but call less (though not significantly so) than naive chicks at the higher temperature. 4. 4. The increase in the rate of calling with age at the higher temperature is not statistically significant in chicks reared in isolation. This suggests that separation from the social companions becomes an important factor in eliciting calling in chicks with social experience. This was confirmed by a number of other experiments. 5. 5. The relevance of these results to various hypotheses about the factors causing the end of the sensitive period for imprinting is considered.