Today’s blog is by Senior Conservation Scientist, Steffen Oppel, working out on Gough Island.

Gough Island is a very remote island in the South Atlantic Ocean – part of the UK Overseas Territory of Tristan da Cunha. Millions of seabirds breed on this World Heritage Site, but many are threatened by invasive non-native house mice. In 2021 the RSPB is attempting to restore this island by removing the mice, and a dedicated team of conservationists has been on Gough since February to contribute to this Herculean task.

Three albatross species breed on Gough Island, the two smaller species (Atlantic yellow-nosed and sooty albatross) breed during the summer, while the larger Tristan albatross has such a long breeding season that it takes almost an entire year for the chicks to fledge. As the days on Gough get shorter, the breeding season of the two smaller albatross species draws to a close.

Since late March, the fledglings of Atlantic yellow-nosed albatrosses have been launching themselves into the air for the first time. Devoid of the raucous begging calls of thousands of albatross chicks, the lower parts of the island now appear eerily silent during the day (they come alive at night, when thousands of petrels arrive). The first flight of an albatross is, however, not a painless affair – and some don’t even make the short distance to the sea.

Atlantic yellow-nosed albatross chick on Gough Island © Steffen Oppel

The RSPB team counts Atlantic yellow-nosed albatrosses – which are locally known as ‘mollies’ – in several study areas on Gough, and measures the breeding success by also counting large fledglings later in the season. In the summer 2020/2021 breeding season there were 285 breeding pairs in these study areas that raised 165 fledglings (including one we followed which survived a mouse attack) – a breeding success of 58%, which is similar to the average over the past 10 years. That number, however, does not include what may happen to the fledglings after leaving the nest.

Mollies prefer to nest amid the lush vegetation in the lowland areas of Gough, often under dense Phylica trees where their nests are sheltered from the elements. While this shelter protects the growing chick from the worst rain and wind, this benefit comes at a cost: when the chick is ready to fledge, it cannot simply hurl itself off a cliff or mountaintop and become airborne.

Atlantic yellow-nosed albatross breeding under an old gnarly Phylica tree © Steffen Oppel

Once their wings have fully grown and their parents have stopped delivering food, molly fledglings need to waddle through thick vegetation to find an elevated spot from where to take off. Although flying is easy for albatrosses once they are in the air, they need some wind to actually take off. Ridges and cliff edges are suitable launching spots, and fledglings can often be seen practising wingbeats prior to actually attempting to take off.

Albatross fledgling practicing wingbeats © Steffen Oppel

Finding a suitable launch pad is just the first step: once a fledgling has mustered the courage to hurl itself into the air, it must avoid the various hazards the island poses to actually get to the sea. The sea is not far away – often just a few hundred metres as the bird flies - but treacherous terrain means that some fledglings become trapped in steep-sided narrow valleys from which they can no longer take off.

Albatross fledgling lost in a forested steep-sided creek – it is very difficult for an albatross to walk out of there, and there is no way to spread its massive wings and take flight © Steffen Oppel

But there is no safety in the air either: the lumbering and unsteady wingbeats of a first-time flier are easily spotted by the native Tristan skuas and southern giant petrels – two scavenging species who would happily see a fledgling crash-land to then devour its carcass. Both skuas and giant petrels frequently harass and attack fledging albatrosses in mid-air, turning the incredibly short distance between its nest and the sea to a baptism of fire for any fledging albatross.

Some never make it to the sea. Either trapped in a narrow valley, downed by attacking petrels or skuas, or just through miscalculation of the winds and their glide trajectory, some albatross fledglings end up grounded. On the ground, giant petrels are much stronger than mollies. Last year, the RSPB found that giant petrels can even kill adult albatrosses on their nest, hence a fledgling is usually no match for these birds.

This Atlantic yellow-nosed albatross fledgling never made it out to sea. A southern giant petrel killed it and is consuming its fresh carcass © Steffen Oppel

Despite the gruesome untimely death of some chicks (lost to mice) and fledglings, the molly population on Gough appears to be stable (592 breeding pairs were counted in October 2020, similar to the average over the last few years). Only time will tell whether the attacks by giant petrels are increasing and affecting the albatross breeding population.

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