Trends in breeding numbers and survival of black-browed (Thalassarche melanophrys) and grey-headed albatrosses (T. chrysostoma) breeding on Macquarie Island

Black-browed (Thalassarche melanophrys) and grey-headed (T. chrysostoma) albatrosses are globally threatened seabirds that breed on remote subantarctic islands. Population trends of black-browed and grey-headed albatrosses breeding on Macquarie Island were described using historical data in conjunction with data from a more intensive ten year monitoring program. Survival estimates were also calculated for both species over similar time frames. Breeding numbers and survival rates of black-browed and grey-headed albatrosses appear to have remained relatively stable since the mid 1970s. There was no conclusive evidence of survival varying over time and it is unlikely that these populations have been impacted significantly by extra mortality due to fisheries activities. This is in contrast to most other subantarctic populations of these species and may be attributed to their foraging ranges not overlapping significantly with areas of high fisheries activities. However, both species forage in areas of new and expanding legal and illegal fishery operations. Due to their extremely small size, these populations remain chronically vulnerable to any elevated levels of mortality