Falklands Conservation

Black Browed-Albatross
Census and Population Trends in the Falkland Islands

Every year in the last week of September the black-browed albatross returns to the Falkland Islands to breed. By early October, the previously deserted colonies are full with birds, busy and noisily nest building and undertaking the intricate preening and dancing of courtship.

These majestic birds will have spent the entire winter at sea, gliding effortlessly across the South Atlantic in search of food.

Each year they will return to the same colony and amongst thousands will find their partner, with who they pair for life. For juveniles returning for the first time it may be the first time they have touched land in over 7 years.

Yet every year fewer birds return. Nineteen of 21 species of albatross are now classified as threatened and the black-browed albatross of the Falklands is no different. The greatest threat to this species is increased mortality at sea from fishing activities beyond the Falklands, meaning that each year some birds will leave never to return - and their mate will wait in vain.

The Falkland Islands, holding 65% of the world population of the Endangered black-browed albatross, are critical to the conservation of the species. Falklands Conservation, the largest island-wide conservation charity in the Falklands, and affiliated to BirdLife International, have worked to tackle the decline for the last 8 years, both ashore within the colonies and at sea working with the fishing industry. In 2000 the first island wide census was undertaken and a programme of at-sea observers was started to quantify mortality within the various Falkland Islands fisheries.

The black-browed albatross breeds on twelve different islands to the south and west of the Falklands archipelago.

Falklands Conservation monitors the population on a 5-year cycle. Complete censuses are completed every five years with annual monitoring of selected colonies in the intervening years. Two complete censuses have been completed in November 2000 and 2005. During this period the population has declined by 14,852 breeding pairs from 414,268 breeding pairs in 2000 to 399,416 breeding pairs in 2005. This represents a population decline of approximately 0.7% per annum. Although this decline is less than at other sites within the species range, for example an annual population decline of 4% is recorded at South Georgia, it is still highly significant for such a long-lived species.

The two most important sites in the Falklands are the colonies on Beauchene Island and Steeple Jason that together represent 70% of the Falklands population. Due to the importance of such sites previous counts limited to these sites provide an important long-term insight into overall population trends. Additional survey data is available for a range of other sites but due to the small proportion of the overall population, such data is less significant.

The huge albatross colony on Beauchêne Island with over 100,000 birds. Credit: Nic Huin.

From previous a census of Beauchene Island undertaken by Peter Prince of the British Antarctic Survey in 1981 and a census by Falklands Conservation in 2005 it has been determined that the overall number of breeding pairs on that Island has declined by about 56,000 breeding pairs or 35% over this time. On Steeple Jason a previous census in 1987 shows a reduction of 43,000 breeding pairs or a 20% decline between 1987 and 2005.

Falklands Conservation albatross population censuses are conducted by three methods depending upon the characteristics and size of each of the colonies. Smaller accessible sites are counted by direct observation by a number of observers. Inaccessible sites are counted by photography. The largest sites are counted by first mapping and measuring the area of the colony and then conducting a number of sample lines through the colony to calculate the average nest density within the area of the colony. Whilst there is a difference in the accuracy of each method, by ensuring that each colony is counted by exactly the same method each year and exactly the same time of year, the results are directly comparable and trends can be identified.

Our data shows that the decline of the species is not constant at all the breeding sites. At three sites the population has increased although at only 2 of these were the increases statistically significant (North Island and Grave Cove). The remaining nine sites declined from –0.1% (New Island) to the largest reduction of –34.1% (Elephant Jason). Declines were significant at 3 sites. If the data from all sites is combined the annual decrease of 0.7% is significant.

Measuring the black-browed albatross colony on Steeple Jason Island. Credit: Oli Yates

Colony nest density and area are measured in the large colonies on Beauchene and Steeple Jason Islands. The area is measured by both GPS and by laser range-finder whilst nest density is counted in 10m wide strips running across the breadth of the colony at intervals. Colonial seabirds tend to have an optimum nesting density that ranges between certain defined limits a compromise between avoiding predators and not being so closely packed to cause disturbance and be within mutual pecking distance. Therefore in a declining population to maintain breeding density the colony must shrink. Both the census area calculations and historical photographs support that such shrinkage has occurred. Combining the areas of the colonies on Beauchene Island and Steeple Jason represents a 13% loss from original estimates or 73,000m2.

These photographs show significant reductions in colony boundaries. They were taken on Beauchêne Island, the one on the left in 1980 and the one on the right in 2000.

Tackling the declines in black-browed albatross numbers has been a major focus of Falklands Conservation’s efforts in recent years. Work with the fishing industry in Falkland waters has seen a dramatic decline in accidental mortality associated with fishing activities. Since work with the fishing industry began in 2000 mortality in the longline fleet has been reduced 100 times from 0.02 birds / 1000 hooks to 0.002 birds / 1000 hooks whilst in the trawl fleet mortality has been reduced by 90%. Mortality is now considered to be at sustainable levels in the Falklands Fisheries.

This work has placed Falklands Conservation and the Falklands fishing industry at the forefront of mitigation research worldwide. However urgent further action is required to provide outreach and assistance to other fisheries across the Patagonian shelf, to address bycatch and to ensure land management at sites does not result in additional risks to the populations. Falklands Conservation will be working through the international Agreement on the Conservation of Albatross and Petrels and with Birdlife International’s Global Seabird Programme to address these issues so that we can ensure that albatrosses remain one of the enduring symbols of the southern oceans.

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