Antipodean Albatross, Diomedea antipodensis, is a breeding endemic of New Zealand. It is known to breed on only a very limited number of islands; Antipodes Island, the Auckland Islands (Adams, Auckland and Disappointment), Campbell Island and Pitt Island (one pair since 2004) (Miskelly et al. 2008, ACAP 2012). The species does not breed every year, and may defer up to two years between breeding attempts (ACAP 2012), and so the number of individuals breeding annually does not equate to the number of individuals in the population. G. Elliot and K. Walker (unpubl. data in ACAP 2012) roughly equated the global population size to be 44,508 mature individuals based on an approximate annual breeding population of 8,050 breeding pairs, with the vast majority of individuals breeding on Adams and Antipodes Islands. However, since 2004 there has been a dramatic decrease in the population size and number of nests found on these two islands (see Elliott and Walker 2014, Elliott et al. 2016), and so the population size is likely smaller than this now.
The recent surveys of Antipodes and Adams Islands (Elliott and Walker 2014, Elliott et al. 2016) combined with unpublished data suggest that declines may be 97.6% over 3 generations (82 years) (K. Walker and G. Elliott in litt. 2016). Modelling exercises have also predicted very large declines. Combing the rate of decline for Antipodes (Edwards et al. 2016 per K. Walker and G. Elliott in litt. 2016) and Adams (Francis et al. 2015 per K. Walker and G. Elliott in litt. 2016) give an annual decline of 5.7% per year, equating to a 99% decline over 3 generations. However, we urge caution when extrapolating population trends such a long distance into the future, based on only a very small period in the past. This is emphasised by the data presented in Elliott and Walker (2014) and Elliott et al. (2016), which appears to show the population was stable or increasing prior to 2004, and so we must be wary that these recent declines may in fact be related to a population cycle rather than a true decline.
That said, the rate of decline is worrying, and there are plausible threats to explain population declines. Species bycatch in longline fisheries is a key threat to this species (ACAP 2012). The degree of threat from fisheries is also currently increasing as individuals are travelling further to find food, particularly females, and it is the female population that is declining faster than the male population (see Elliott et al. 2016). This now means that there is a sex imbalance within the population, which again reduces the effective population size. Changing oceanic conditions may also mean lower food availability (Elliott et al. 2016), while invasive species may be leading to some land-based mortality (Taylor 2000). Thus we may be able to suspect that declines may continue at least some way into the future.
As already stated above, it appears to be a bit premature to estimate such high levels of population decline from such a relatively short period of time relative to the 3 generation period for this species. However, we do also acknowledge that the decline does appear to be large for such a relatively short period of time. Taking approximate numbers of breeding birds from the figures in Elliott and Walker (2014) and Elliott et al. (2016), and restricting the number of mature, breeding individuals to the number of females x2 (due to sex imbalance number of males is likely to be > number of females, and so there will be ‘spare’ adult males that cannot breed), would roughly equate to a decline of c.52% between 2004 and 2014. If all adults were included, the decline would equate to roughly 44%, but given that threats may continue into the future it may be assumed that the population will decline sufficiently in the subsequent 72 years that the rate of decline may be >50% over a 3 generation period that encompasses the past and the future. Therefore, it is proposed that this species be uplisted to Endangered under criterion A4bde, noting that if the current trends were to continue it is likely that the species may warrant further uplisting in the future.
We welcome any comments regarding this proposed uplisting.
ACAP. 2012. ACAP Species Assessment: Antipodean Albatross Diomedea antipodensis. Available at: https://acap.aq/en/acap-species/289-antipodean-albatross/file
Elliott, G.; Walker, K. 2014. Antipodean wandering albatross – population study. Report prepared for Department of Conservation.
Elliott, G.; Walker, K.; Parker, G.; Rexer-Huber, K. 2016. Gibson’s wandering albatross census and population survey 2015/16. Report on CSP Project 4655, prepared for Department of Conservation.
Miskelly, C. M.; McNally, N.; Seymour, R.; Gregory-Hunt, D.; Lanauze, J. 2008. Antipodean Wandering Albatrosses (Diomedea antipodensis) colonising the Chatham Islands. Notornis 55(2): 89-95.
Taylor, G. A. 2000. Action plan for seabird conservation in New Zealand. Department of Conservation, Wellington.