BirdLife: The Magazine Jan-Mar 2018 - Page 31

more than halved in the decade between 2004 and 2014. What could be the reason for this catastrophic decline? There are many likely causes. Warming oceans are decreasing the albatrosses’ food supply, meaning that they need to travel to new areas to find food. Antipodean Albatrosses are specialists in low-energy flying, riding updrafts created by the wind and waves and covering vast distances while rarely needing to flap their wings. However, their increasingly arduous journeys are putting them in the paths of fishing boats. And that’s where the problems begin. Antipodean Albatrosses are mainly scavengers, plucking squid and fish from the surface of the waves or plunging into the water in shallow dives. So it’s no wonder they are attracted to fishing boats and the discarded delicacies they provide. Unfortunately, many albatrosses end up being accidentally impaled on the baited hooks of longline fisheries. In fact, in 2006 a single fishing trip in New Zealand waters ensnared 58 Antipodean Albatrosses on longline hooks. But the impact isn’t an equal one – twice as many females are being killed as males. This is because the females are the ones who have changed their foraging range. In previous years, they remained largely around New Zealand. But tracking data since 2011 shows they have started venturing both further north and much further east to the coast of South America. This means they now overlap with a far greater number of fisheries where they are at risk of being killed, creating a serious imbalance in the sex ratio of the population. With two males for every female, far fewer breeding pairs are able to form, and an Jan-Mar 2018 • birdlife The Antipodean Albatross’s population has halved in a single decade. Photo Duncan Wright 4 The Albatross Task Force introducing bird-scaring lines in Namibia. Photo Kondja Amutenya army of bachelors is left over. This significantly reduces the species’ potential to raise the next generation and build up their population again – instead, further declines are predicted. If the current rate of decline continues, in 20 years there will be fewer than 500 pairs left. 7 with two males to every female, fewer breeding pairs are able to form and an army of bachelors is left over More encouragingly, another albatross species has moved the opposite direction on the Red List this year. With its imposing silhouette, the Black-browed Albatross Thalassarche melanophris is one of the most iconic seabirds in the Southern Hemisphere. And they seem to be on the increase. On the Falkland Islands (Islas Malvinas), both aerial and land-based surveys have shown their population rise by 4% a year between 2005 and 2010, and Chilean populations are showing a similar improvement. And since these archipelagos hold some of the highest numbers of breeding individuals, we can be confident that the population as a whole is on the up. In fact, there are now estimated to be 700,000 breeding pairs globally. As a result, this year the Black-browed Albatross was downlisted from Near Threatened to Least Concern – following on from an encouraging precedent set in 2013, when it was downlisted from Endangered to Near Threatened. But the change isn’t simple – although the overall population is increasing, on the island of South Georgia (Georgias del Sur) it has actually been declining by an estimated 1.8% a year between 2005 and 2014. This is a separate population with a different foraging range, and their situation needs to be addressed. And Black-browed Albatrosses everywhere are plagued by similar bycatch issues to their 31