Wing and primary growth of the Wandering Albatross

We investigated the relationship between body mass and the rate and pattern of feather growth of the four outermost primaries of Wandering Albatross (Diomedea exulans) chicks. Maximum growth rates were similar (4.5 mm day^-1) for all feathers and between sexes, although primaries of males were significantly longer than those of females. There was a distinctive pattern to primary growth with p10 grown last, reaching its asymptote just prior to fledging. Primaries growing did so at different maximum rates; thus p7 reached its asymptote at an earlier age than p8 or p9, but maximum growth rates were the same for all primaries. Maximum growth rates of p7 and p8 were significantly correlated with chick mass at the start of the period of primary growth, and chick mass also was correlated with age at fledging. The heavier the chick, the earlier it grew its primaries and the younger it fledged. Fledging periods for Wandering Albatross chicks may be constrained by the time required to grow a full set of primaries. We suggest that the observed pattern of feather growth is a mechanism to minimize potential wear of the outer primaries prior to fledging.