Bay of Isles, South Georgia
Early this morning (and I do mean early!), we made a pre-sunrise landing at what is perhaps the most important site in the Bay of Isles…the famous Salisbury Plain. This is the largest area of flat, open land in all of South Georgia, and it is reputed to contain the second-largest king penguin colony on the island (after St. Andrew’s Bay, located farther to the southeast). No one seems to know for sure, but it is estimated that 80,000 to 100,000 pairs of kings nest here.
Conditions for photography were nearly perfect this morning, and we witnessed some remarkable behaviour within this colony. We were amazed to observe how the incoming birds, returning from days of feeding on mctophids (deep sea fish that can luminesce), were shiny clean and full-bellied and made a long march in single file to the colony from a landing area far removed. However, the ones in the colony that switched out with the returning mates walked straight down to the beach below the colony and then entered the water and cleaned themselves before setting off on their turn to feed. It was all one way traffic. Several guests asked us naturalists why they do this, and the best answer seems to be…well, they’ve always done it like this. Sometimes it’s hard to understand what goes on in the mind of a penguin. One penguin tried to buck the system and take a short cut across the shallow, muddy quagmire separating the high beach ridge from the breeding colony. He suffered the consequences and was shunned by his brethren when he tried to cut into the marching line (see Figure 1).
Several of us made a very interesting hike out onto the plain towards the massive Grace Glacier, while others walked down the beach to the base of the colony and then climbed up into the tussac grass along the far edge of the colony. This gave some great views of the adults and their tiny chicks. In addition to king penguins, the surrounding lands hold fur seals, elephant seals, skuas, giant petrels, South Georgia pintails, and lots of other species.
One particular animal sighting really stood out. Those who enjoyed a Zodiac cruise along the shoreline this morning saw a true behemoth resting on the flat pebble and sand ridge near the western end of the main beach. This impressive beast was surrounded by penguins and fur seal pups, all of whom were potential prey, but they seemed to treat it like some common elephant seal. However, this was no elephant seal…it was a leopard seal! In fact, it was the biggest leopard seal any of the staff, who together have many years of experience with leopard seals in Antarctica, had ever seen. It probably measured at least 4.25 meters (14 feet) long and weighed perhaps 700 kg (1,500 pounds). King penguins are obviously a good food source (see Figure 2).
In the afternoon, we sailed a short distance out to the islands in the Bay of Isles, where we spent the rest of the day exploring Prion island and the surrounding waters. These islands are free of rats, so the region is very important for some of the smaller breeding sea birds, such as prions and white-chinned petrels, and especially for the only Antarctic songbird…the South Georgia pipit. Numerous giant petrels and wandering albatrosses also nest on the islands. The South Georgia government has closed most of these islands to visitors, but we had a special permit to land on Prion Island.
Over several hours, we all managed to climb up through the tussac on a newly constructed boardwalk and observe several nesting wandering albatrosses. These enormous birds have the longest wingspan of any living species and are objects of grace and beauty both in the air and on their nests. The Zodiac cruises were also fun and during them we enjoyed watching the movements of leather kelp in the wave surges along the rocks and we managed to see several rare South Georgia pipits...this gave the serious birdwatchers among us some real bragging rights.
