In our final visit to the UK Overseas territory of St Helena, Jonathan Hall looks at the importance of the island for its marine life.
Seabird and Marine Conservation
Our story so far as concentrated on the life clinging to the tiny island itself (you can catch up here on the last blog by Daniel Pullen). Daniel and I were also on the island to discuss opportunities for further seabird research and marine conservation.
Situated in the central South Atlantic, St Helena is responsible for a large and relatively little known area of ocean (known as its Exclusive Economic Zone, or EEZ). As one of the only landmasses in a vast sea, it is also of huge potential importance to seabirds as a nesting site.
Before its discovery in 1502, St Helena would likely have been home to vast seabird colonies, and two species of petrel found nowhere else on earth. Many of these were sadly driven from the main island by introduced predators, especially cats and rats. Today, many seabird species are therefore restricted to the small offshore islets and stacks around St Helena. Stacks such as the remarkable Speery, pictured below, a jagged rock shaped like a shark’s tooth which juts up out of the water to the south of the island.
Whilst the cliffs on the main island are relatively empty, Speery island (on far right) is a 130m high offshore stack home to many seabird species
The south of the island is exposed to the prevailing current and seas, so is extremely hard to sail around, with the consequence that many of these islands have been very seldom visited.
One of our teams recently discovered that white-faced storm petrels breed on one of the islands off the north shore, a first record for St Helena, so who knows what other species may still be clinging on in very small numbers?
One remarkable good news story however is that whilst the main island is still home to cats, rats and a whole panoply of introduced species, masked boobies have been defying expectations and recently started to return there to breed after a long absence. This is unique as no predator control is taking place in this area, so is of special interest to seabird scientists. We were fortunate enough to be taken out to the south coast by the St Helena Government’s marine conservation team and staff of the St Helena National Trust, our partner organisation, to see where these birds are starting to recolonise.
It’s a rugged and remote place, as you can see from the photo below, but a wonderful story of nature starting its own comeback. The area also contains some of St Helena’s characteristically colourful place names- can you spot the rocks known as the Gorilla’s Head, or Asses Ears?
The white areas on top of the ridges in the circles are nests where masked boobies have started to recolonise the island. It’s a remote spot!
One area where we also hope to work in partnership with local conservationists is to use some of the RSPB’s expertise in seabird tracking. By monitoring where seabirds are foraging at sea, we can learn much more about which marine areas are likely to be rich in marine life and thus perhaps need special protection. Given that St Helena’s seas are so unknown, this will be an exciting first step in establishing the scientific evidence base we need in order to best protect marine life.
This summer a few seabirds were given experimental GPS loggers. Unfortunately bad weather and mechanical failure hampered a lot of the data recovery; we did retrieve one tantalising set of tracks from an individual masked booby. It’s always very exciting getting the first seabird tracking data for an island, as we have no idea where these birds will be heading, but this individual was consistently heading east for as far as 85km. Much more data will be needed at different times of year to build up a more complete picture, but it’s an exciting first step in increasing our knowledge.
If you click on this link below you should see the route of the masked boobie (ed)
And speaking of technology helping conservation, I also had a seabird sound recorder in my bag to take out to our partners. This will be used to try to build up a better idea of where Madeiran storm-petrels may be nesting around the island; its most exciting use will be to follow up some intriguing anecdotal tales. Several people on the island have reported hearing strange noises in the night around some of the most remote cliff areas, describing them as being similar to a baby crying. There is a very very small chance that this could be a record of the long-thought extinct St Helena petrel, which could be hanging on in tiny numbers on some of the steepest cliffs (400m+) or offshore rocks where introduced predators cannot reach them. We can’t be sure what they sound like, and they may well sadly be extinct, but the chance to gather some more sound data and see if we hear anything unusual is too good to pass up...
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