Contents

11 October 1974
Vol 186, Issue 4159

About The Cover

Giant petrel (Macronectes giganteus) incubates its egg on a barren island off the Antarctic peninsula. The evolution of adult care of eggs has produced a variety of incubation patterns and nest structures. Interactions between physiological and behavioral mechanisms provide thermoregulation for the developing new generations of avian species in a fluctuating external thermal environment. See page 107. [Fred N. White, University of California, Los Angeles]