Geographical variation in morphometry of black-browed and grey-headed albatrosses from four sites

Differences in morphometry between five populations of black-browed albatro sses (Diomedea melanophrys) and four populations of grey-headed albatrosses (D. chrysostoma) are examined. Two clear groups of black-browed albatrosse s are evident, with birds from the subspecies Diomedea melanophrys impavida showing significant differences in several variables from those from the s ubspecies Diomedea melanophrys melanophrys. For groups from the latter subs pecies, birds from South Georgia had larger measures than those from Kergue len. A similar pattern to that of Diomedea melanophrys, melanophrys was fou nd between the groups of grey-headed albatrosses. Analysis of foraging dist ances relative to adult body-size index and the duration of chick-rearing p eriods suggests that differences in chick-provisioning rates between popula tions of conspecifics could account for at least some of the observed diffe rences in adult morphometry.