Scott A. Hatch 1990 <p><span>I monitored the incubation schedules of Fulmars </span><i>Fulmarus glacialis</i><span> in an Alaskan colony by observing nests where the male and female were of different colour phases. Complete shifts of up to 16 days were recorded; the average shift in mid-incubation was 4–6 days. Mean shift length was inversely correlated with hatching success in 5 years, suggesting that Fulmars adjusted their foraging patterns to annual differences in food availability. Males assumed the larger share (55%) of incubation on average, and a larger share in years with lower hatching success. Serial correlation in the length of incubation shifts had two components - the influence of prior shift lengths on time spent foraging and individual variation. Failure of the male to relieve the female soon after laying resulted in a few breeding failures and egg losses were associated with exceptionally long shifts throughout incubation.</span></p> application/pdf 10.1111/j.1474-919X.1990.tb00275.x en Wiley Incubation rhythm in the Fulmar <i>Fulmarus glacialis</i>: Annual variation and sex roles article