It is as tiny as a small apple. Its elegance is streamlined and monochrome. And, July marks only the second time that it has graced the Overberg with its presence – this time, it’s alive and well.
The first time a diving petrel was recorded in southern Africa was in 2021 when researchers found a deceased one on a beach near Cape Town.
On Friday 24 July, one of southern Africa’s smallest and most remarkable seabirds, a Common Diving Petrel, scienifically referred to as a Pelecanoides urinatrix, was spotted in the Greater Dyer Island ecosystem.
“Measuring just 19 to 23 centimetres long and weighing 120 to 200 grams, about the weight of a small apple, it is perfectly adapted for life at sea,” says Christine Wessels of Marine Dynamics. “What makes this sighting so exciting is just how rarely they are recorded from mainland South Africa”.
But “despite its tiny size, it is an exceptional diver, using its short wings almost like flippers to ‘fly’ underwater in pursuit of prey”.
This seabird feeds primarily on krill, copepods, amphipods and other small crustaceans (a type of invertebrate animal with a hard outer shell, jointed legs and two pairs of antennae, such as crabs, lobsters and shrimp). It also feeds on tiny fish and squid and dives repeatedly beneath the surface to forage.
“Above the water, it flies low and fast over the waves with rapid, whirring wingbeats and rarely glides,” Wessels explains. “When disturbed, it is more likely to dive beneath the surface than take to the air, making it surprisingly difficult to observe.”
Remote islands
The diving petrel often breed on remote islands scattered throughout the Southern Ocean. These parts include South Georgia, the Prince Edward Islands, Crozet, Kerguelen, New Zealand, Tasmania and islands off southern Chile.
Post breeding season, they often disperse widely across the cold, nutrient-rich waters of the Southern Ocean.
They often travel hundreds and sometimes even thousands of kilometres between feeding and breeding grounds while spending almost their entire lives at sea.
“For birders, a Common Diving Petrel is a species that many hope to see but few are fortunate enough to encounter,” says Wessels.
She adds that each observation contributes to the understanding of seabird distribution and oceanic ecosystems for scientists. “And for our guests, it is another reminder that every marine safari is unique.”
First record
In 2022, Peter G. Ryan, Vincent L. Ward and Susan M. Miller published a scientific paper confirming the first record of the common diving petrel from continental Africa.
In the paper, titled “First Record of a Common Diving Petrel Pelecanoides urinatrix from Continental Africa and a Summary of Diving Petrel Distribution in the Southern Ocean” – the authors note that these birds are typically found 1 500 to 2 000 kilometres southwest of Cape Town during March. Other populations may be found even farther south in Antarctic waters.
“Their appearance along the Southern African coastline remains exceptionally uncommon,” explains Wessels. “That makes every sighting in the Greater Dyer Island ecosystem something special”.
For the Marine Dynamics and Greater Dyer Island team, the marine ecosystem “continues to surprise us with unexpected visitors from the wider Southern Ocean”.
The seabird and marine sanctuary is known and acclaimed for its extraordinary marine diversity wildlife. Some of the more common wildlife species include Southern Right Whales, Bronze Whaler Sharks, Cape Fur Seals, African Penguins as well as several dolphin species.
“As someone who still keeps a Roberts Bird Guide close at hand, I continue to be amazed by the feathered visitors that grace these waters,” Wessels says. “Every trip offers the possibility of something unexpected and this tiny seabird is proof that even the smallest wildlife encounters can become unforgettable moments.”
