The population of endangered Short-tailed Albatrosses Phoebastria albatrus has gradually increased through great conservational efforts, but their only two breeding sites, Torishima Island and Senkaku Islands, have a high risk of volcanic eruption or political problems. The Short-tailed Albatross Recovery Team has indicated that, to achieve recovery of this species, additional breeding colonies of the Short-tailed Albatross must be established. Their proposed plan is to artificially rear chicks translocated from Torishima Island at new safe sites. To evaluate the feasibility of this approach, it is important that trials first be conducted with related albatross species. In early March of 2006, 10 Laysan Albatross P. immutabilis, approximately one month of age, were captured at Midway Atoll and moved to Kauai Island, where we attempted to rear them to fledging in early July. Chicks were provided daily with 250-450 g of squid and lake smelt as food. This amount was estimated from a regression equation derived from the proportion of daily amount of food to body mass and daily increase of body mass in the Grey-headed Albatross Diomedea chrysostoma. This species has a similar growth pattern as the Laysan Albatross. We also provided vitamins and other supplements to compensate for nutritional deficiencies in the diet, along with some electrolyte solution to prevent dehydration. Three and two chicks died during one month after beginning to rear and just before fledging, respectively. One chick with an injured wing and no prospect of flying was housed at Monterey Bay Aquarium. The remaining four chicks fledged successfully. Sources of mortality included exposure and bacterial infections in their gastro-intestine. Although we had to feed them greater amounts of food than that estimated from the regression, the captive chicks achieved the same trajectory of mass growth as wild chicks. Improved hygiene of food and equipment, and better techniques for handling of chicks will be adopted in future rearing efforts.
2008 公益財団法人 山階鳥類研究所