How Far Has the Short-tailed Albatross Translocation Project Progressed?

Abstract

Restoration or establishment of colonies using translocation and hand-rearing can be an effective tool for conserving seabirds. However, few such projects have considered the defined goals, the best action for a given set of objectives, and a well-designed post-release evaluation. Many breeding colonies of Diomedeidae are threatened with extinction. The entire breeding population of the threatened Short-tailed Albatross Phoebastoria albatrus is restricted to just two sites, Torishima and the Senkaku Islands, and neither site is secure due to volcanic activity or political instability. To facilitate the recovery of this species by establishing at least one additional colony (final goal: more than 75 breeding pairs), during 2008–2012, a total of 70 post-guard phase chicks were translocated from Torishima to a safe, former breeding site, Mukojima where social attractants were deployed, and where chicks were hand-reared for 100 days until fledging. During the five-year study, fledging success was 99%. Hand-reared chicks had comparable or superior health and similar rates of immediate post-fledging survival to naturally-reared chicks on Torishima. During one month after fledging, the more northerly dispersal of hand-reared birds compared to naturally-reared birds suggests the ability to adjust to a new departure location. Forty-two percent of hand-reared birds (n=29) returned to the translocation site (Mukojima) at least once per breeding season, of which 83% (n=24) also visited Torishima. The occurrence of hand-reared birds returning each year was lower at Mukojima than Torishima. The first breeding attempt occurred five years after the first translocation. Two pairs recruited to Mukojima and nine pairs recruited to Torishima by 10 years after the first translocation. Our preliminary results suggest that even though more translocated and hand-reared albatrosses visited and recruited to their natal island compared to the translocation site, the early re-establishment of breeding by Short-tailed Albatrosses at a historic nesting site 80 years after extirpation would not have occurred without this initial translocation effort. Further study of long-term monitoring is needed to fully understand formation of breeding colonies in long-lived and slow to mature seabird species.