Blue Petrel Halobaena caerulea

Rather small, attractively patterned petrel of cold subantarctic waters; not seen from mainland. Sometimes accompanies ships, especially near breeding islands and with groups of similar-sized and superficially similar prions. Blue Petrel told from all prion species by dark cap, half collar, and bold white tail tip. Also note differences in flight pattern; often a bit stronger and banks higher in strong winds.