| Research Abstract |
Nutritive condition of oil-polluted rhinoceros auklets (Cerorhinca monocerata) found dead along the coasts in Shimane Prefecture, early January 1986, was analyzed in comparison with the other dead auklets caused by natural emaciation and fishery accidents. Oiled birds were all in mal-nutritive condition, similar to the coastal emaciated dead birds. The items examined in this study, such as fresh and dry weights of body, pectoral and leg muscles, oil gland, liver and marrow of leg bones as well as their lipid weights were almost all useful as indices of the nutritive condition. Moreover % lipid weight contained in pectoralis minor and % water weight contained in femur marrow seemed to be the most useful items to determine the extremely mal-nutritive condition. Lipid reserve of this species was smaller than Proceralliiform and other water birds, even in their healthy nutritive condition. On the contrary, skeleton and pectoral muscle weights of the auklets were heavier than the above compared birds. This heavy bodily composition can be attributed to this species' adaptation for deep water foraging, while their low lipid reserve may reflect the underwater pursuing ability and local movements (which do not require much lipid). Owing to this low lipid reserve, the alcid species may tend to quickly fall into mal-nutritive condition and may die in short periods when victimized by oil-pollution of the sea.
Nutritive changes of their chicks from hatchlings to fledgings were also analyzed by same methods and they were compared with the ones of Procellariiforms' chicks (OKa 1986) to know a nutritive strategy of this diving species.
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