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The diet of two small burrow dwelling petrels, Dove prion, Pachyptila desolata and Blue petrel Halobaena caerulea, was studied at the subantarctic island of South Georgia by quantitative analysis of 246 food samples regurgitated by adults about to feed chicks. Crustaceans, and particularly krill Euphausia superba, predominate in both species' diet but fish is considerably more important to the Blue petrel. Other dietary differences between the species chiefly involve the relative proportions of krill, copepods (nearly exclusive to Dove prion) and seven amphipod species taken.

There is no overlap in the species' chick feeding periods but food differences are likely to reflect prey selection rather than resource availability; differences in prey size are ascribed to use of different feeding techniques particularly relating to bill structure and function. Data on frequency of chick feeding, proportion of oil and presence of pumice in food samples are used to indicate that the Blue petrel feeds further away from the breeding colony than the Dove prion. The significance of the various adaptive differences is discussed.