Incubation under natural conditions in the kittiwake gull, Rissa tridactyla

Abstract

The nest attendance and activity of kittiwake pairs were monitored during incubation using radioisotopes. Overall, females performed 54% of incubation and males the remainder. Paris differed consistently in their methods of sharing incubation. Partners met only briefly when they changed over incubation duties, alternating rapidly during early incubation but later only about twice each day, these changeovers occurring usually after dawn and in the late afternoon. Less consistent incubation attendance occurred in males, and was often compensated for by the females. Detailed changeover patterns showed considerable irregularity, both within and between pairs, apparently unrelated to environmental parameters.