Hi there. My name’s Cian Luck. I graduated from the school of BEES in UCC with a BSc in Zoology in 2012, and was lucky enough to spend the following year in BEES completing a research masters on the diets of grey seals and harbour seals in Irish rivers. During the masters I got a bit hooked on seals and now here I am, working for the British Antarctic Survey, monitoring Antarctic Fur Seals and Leopard Seals on Bird Island, South Georgia. Perhaps that was a lot of information in one sentence. I’ll start with where I am.
Bird Island is a small island off the western tip of South Georgia, in the Southern Ocean. It measures just under 5 kilometres long and 800m wide at its narrowest point. While its latitude puts it at 54°South we have the Antarctic Circumpolar Current (ACC) to thank for bringing the Antarctic climate to our doorstep. There are a couple things that make Bird Island such a unique and interesting dot in the Southern Ocean.
- Bird Island is rat free. South Georgia has long had a huge rat infestation problem (since the old whalers brought them ashore). The rats decimated any ground nesting birds they came across, which was a lot. Bird Island is a rat free haven, home to a wide range of bird species, none quite as charismatic as the enormous Wandering Albatross. Roughly 10% of the world’s wanderers call Bird Island home.
- Much of the wildlife (seals and penguins) on Bird Island is dependent on krill. While the waters around BI have a multitude of krill, none of it breeds here, but instead breeds down near the Antarctic continent, and is then swept up to us by the ACC.
In summer we can hold up to 10-12 on base and in winter we fall down to 4 people. Our nearest human neighbours are the folks at the BAS base at King Edward Point (KEP) over on South Georgia (about 8 hours away by ship), and after that the nearest humans are 1,000km away in the Falkland Islands. Instead we’re surrounded by hundreds and thousands of seals, penguins, and birds of all sorts. Our base sits on Freshwater Beach. During the fur seal breeding season we get surrounded on all sides by BIG rowdy males, females calling for their pups, and puppies shouting back. Sleep can be hard to come by at first.
My job title is a Zoological Field Assistant (ZFA), and I’m tasked with maintaining the long-term monitoring of the seals that’s been going on here for the past few decades. During the summer, pretty much all of my time is taken up with the fur seals, with December being a particularly busy month. We have a Special Study Beach (SSB, sorry about all the acronyms, you’ll catch on quick) that’s an enclosed section of beach with a raised gantry that allows me to access the seals without losing an arm or leg. Throughout the breeding season I visit this beach twice a day, every day. Among many other things, I map out which males are holding territories where on the beach, how many females are on the beach each day, and each pup born on the beach gets weighed, sexed, and is given an individual PIT tag (similar to the microchip you might put in your dog). We also give the pups flipper tags once they’re a bit more grown up, in the hope that we can identify the ones that survive long enough to come back and breed on SSB in later years.
Fur seals make brilliant mums, but they’re just not big enough to stay with the pups the whole time from birth to weaning. They have to regularly go to sea to feed and return with fresh milk to feed the pup. Each year we monitor how long the mothers leave the pups unattended by fitting a number of mums with radio transmitter tags that tell us when she’s ashore and she’s at sea.
On top of this, we constantly monitor the fur seal diets by collecting fresh scats each week and sifting through the contents. Not only is this a glamorous job but it’s hugely insightful. By looking at the mean size of the krill in the scats we can keep tabs on the health of the krill stock the seals are feeding on.
There’s plenty more fur seal work that keeps me out of trouble for the summer but those are the big three jobs. In winter, my focus changes from fur seals to leopard seals, which only arrive around May. My main job then is the daily leopard seal round where I walk the same route along the beaches and photograph any leopard seals I meet. This gives us some insight into their behaviour and allows us to build a comprehensive photo-ID database, which we can then use to identify any returning leopard seals and new faces.
When I’m lucky enough to meet a lep on land, after I’ve taken my photos, I approach it as quietly as I can (I’m more clumsy than stealthy), and try to measure it. Obviously these guys are top marine predators, so I can’t quite run a tape measure along its back. Instead, I place two walking sticks, one near the nose (this is fun) and one at the tip of the tail, and I then measure the distance between the two. Close enough. Finally, unless a previous seal assistant has beaten me to it, I give it a flipper tag, and then move swiftly away. This requires a lot of stealth and a very sleepy seal; two conditions that are rarely met. Tagging (a) helps us ID the lep in future, (b) provides us with a little skin sample for genetic analysis, and (c) allows us to sometimes deploy geolocators on the tags; if we’re lucky enough to get these back we can find out exactly where the lep has been.
Now that winter is drawing to a close, my leopard seal sightings are coming fewer and farther between, and soon I’ll be getting ready for the fur seal season which kicks off again in November. I’ve been on Bird Island since November of last year and I’ll be here until next March or April, depending on what the ships are doing, when I’ll hand the job over to the next ZFA in line. Time moves strangely here but I’m sure by the time the ship comes to take me away, I won’t be ready to leave.
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