From the north to the south in a matter of days, WDCS researcher Oli Yates shares his experiences of the orca that make the Falkland Islands in the south-west Atlantic Ocean their home - at least for a small part of the year!
To the south east of the Falkland Islands there is a small, 2 km long island with a lot of charm. The island is uninhabited through much of the year but becomes a busy local attraction in the summer months as people travel there to see the bustling penguin colonies, marvel over the elephant seal bulls fighting for control of the harems and enjoy the sunshine along white sandy beaches.
Myself and a small group working with Falklands Conservation headed out to the island to confirm and document what had long been part of local knowledge – the island was home to another spectacular resident, the orca. Apparently small groups of orcas had been seen over the years, coming close to the sandy shores of Sea Lion Island. When we arrived we found that this was just the tip of the iceberg….
We set up patrols of the main two beaches to the east of the island starting at 5am and continuing through until about 6pm. Long days in some roaring weather conditions were filled with the joy of observing the wildlife of these beautiful islands. Each morning we were met by the sound of the Magallanic penguins enthusiastically calling from their burrows (they sound like donkey’s braying, hence the local name Jackass penguins) and the grunts of the elephant seals as we arrived on the beaches. Initially we only saw the orcas from a distance, a group of five or six individuals passed by with apparent disregard beyond the extensive kelp beds. These sightings offered no more than a confirmation of their presence and it wasn’t until the end of the first trip that we saw their real motives.
By this time, young elephant seal pups had started swimming in rock pools in and around rocky platforms that stretched out from the ends of the long beaches. We soon realised that at the margins of these rocky platforms, the water depth dropped off to at least two meters and got progressively deeper beyond the kelp. During our early morning observations, we found that two of the adult female orcas came to within centimetres of the rocky platforms! They passed silently up and down with just the tip of the dorsal fin protruding from the water. The young elephant seal pups were apparently unaware of the danger that awaited them, but we were breathless as we absorbed the situation.
To our amazement, one of the orcas would spend several minutes perfectly still almost completely submerged with her head just below the water right next to the rocks. During this time they would take the faintest of breaths before submerging in the shallows again. Meanwhile the rest of the group would remain at some distance, perhaps 200 m away playing in the kelp beds. Slowly, the largest female positioned herself in a pool next to the rocks that only filled at high tide. The pool had a narrow entrance, perhaps 1.5 m across and we watched in disbelief as the enormous animal lay motionless with her nose peeking out of the water.
Over the next two seasons we were given a lesson in why they had learnt this behaviour. As the elephant seals made their first forays into the shallows, the orcas lunged from their ambush and were rewarded with energy rich meals at the expense of the elephant seal population. We recorded two groups during our time at Sea Lion Island and a total of 12 individuals that repeatedly visited the rocky platforms and sandy shores to attack the young elephant seal pups. During the second season one of the juvenile orcas had disappeared. We feared this young animal must not have survived the winter as the mother was still present but alone. On our last day, one of the other females arrived with a very young calf staying right at her side.
Of all the animals we observed, only the lead female displayed all of the ambush behaviour that was so impressive. Perhaps what we witnessed was part of teaching the younger animals the tricks to surviving in the harsh Southern Seas.