The Shag Rocks rise dramatically from the wild Southern Ocean, their jagged, swell-swept sides jutting from the waters northwest of South Georgia and, technically, forming part of the South Georgia and the South Sandwich Islands British Overseas Territory. Though small in size and uninhabited by humans, the Shag Rocks play a key role in the ecology of the sub-Antarctic, especially for pelagic bird life!
What are the Shag Rocks?
The Shag Rocks are a cluster of steep, dark volcanic outcrops that emerge abruptly from an otherwise wild and deep sea. The highest reaches around 246ft (75 m), and the surrounding waters teem with vibrant marine life. The rocks themselves are barren and windswept, with no significant vegetation. There is, however, an abundance of guano, or bird droppings, giving the rocks a dirty, off-white color and a strikingly potent smell. Their name comes from the many seabirds, particularly South Georgia shags, wandering albatrosses, and prions, that use the rocks as roosting and nesting sites. Along with the Shag Rocks, another rocky outcrop emerges from the ocean off the coast of South Georgia - the low-lying Black Rock.
Picture by Koen Hoekemeijer
The Shag Rocks were first discovered by the Spanish ship Aurora in 1762 and were named Islas Aurora. However, there is a dispute over whether the Islas Aurora and the Shag Rocks are the same. Many early maps of Antarctica and the southern seas showed groups of so-called 'phantom islands' that later proved to be nonexistent. A noteworthy example of this lies on the other side of the Antarctic continent, the mysterious Emerald Island. The Shag Rocks were given their current and official name by James P. Sheffield and were charted in 1927. The first known landing on the Shag Rocks occurred in 1956, when the Argentine geologist Mario Giovinetto was lowered onto the rocks by helicopter.
Where are the Shag Rocks?
The Shag Rocks are situated approximately 240 kilometers (150 miles) west-northwest of South Georgia and rise from the South Georgia Ridge, an undersea ridge that is relatively shallow compared to the surrounding seas. They lie close to the Antarctic Convergence, where cold Antarctic waters meet warmer sub-Antarctic currents. This convergence creates nutrient-rich upwellings that support vast populations of krill, fish, and squid. As a result, the waters surrounding Shag Rocks are very biologically productive! This, along with the isolated location ideal for nesting, makes Shag Rocks a vital feeding ground for a wide range of pelagic bird species, some of which are endemic to the South Georgia region.
Birdwatching at the Shag Rocks
For birdwatchers, the Shag Rocks are of particular interest. The rocks provide an essential breeding and feeding habitat for several seabird species that rely on isolated, predator-free environments. South Georgia shags are commonly seen perched along the cliffs, while other species, such as wandering and black-browed albatrosses, petrels, and prions, are frequently seen feeding in nearby waters.
Because the rocks are inaccessible and free from human disturbance, they serve as a critical refuge for seabirds during breeding and foraging cycles. This is despite the extremely frigid and often rough weather conditions that regularly batter the rocks. During an expedition cruise to South Georgia, you may have the opportunity to approach the Shag Rocks and observe pelagic birdlife in a truly unique setting!
Although land-based wildlife is limited to birds, the surrounding seas are teeming with life. The nutrient-rich waters attract Antarctic fur seals, southern elephant seals, and, occasionally, leopard seals. Cetaceans such as humpback whales, fin whales, and orcas have been spotted in the area.
Picture by Sara Jenner
Traveling to the Shag Rocks
While landings on the Shag Rocks are not possible due to their steep cliffs and rough seas, we regularly pass close by the rocks on our South Georgia and Antarctic expedition routes. Weather permitting, we may approach the rocks, offering you a fantastic opportunity to observe rare and unique bird species.
Main image by Sara Jenner