Factors affecting primary molt in the gray-headed albatross

mean number of primaries molted by Gray-headed Albatrosses (Diomedea chrysostoma) varied with year and previous breeding experience independently, but was not related to individual reproductive success over a longer period. Within each category of breeding experience, birds renewed fewer primaries during the "poor" year of 1994, when subsequent reproductive success was only 27%, than in 1993 when subsequent reproductive success was 57%. Inspection of individual feathers indicated that the outer primaries were least likely to be renewed during the period of stress. Within each year, birds that failed in their breeding attempt during the previous year renewed fewer feathers than those which reared a chick two years previously, a difference which was probably partly related to the time available for molting. In 1994 only, the date of failure in the previous year was inversely related to the number of primaries molted by males. The arrival mass of males was positively correlated with the number of primaries molted in two out of four seasons. Males and females molted similar numbers of primaries.