The adult male penguin on Sherley’s lap looked like a black-and-white torpedo, fat and round and tapering to the pointed beak. It also looked as if it could explode at any minute and bolt from his grip. Sherley controlled it with both hands, one behind the bird’s head and the other hugging it close to his body.
Biologist Kate Robinson from the University of Cape Town moved quickly to attach a small recording device on its back. She used black tape to secure the electronic backpack to the penguin’s feathers. It was a GPS device that records location, depth of dives, temperature of the water and other information. “We’ll retrieve the logger when he comes back,” Robinson said.
Maps generated by such loggers have shown that these penguins travel about 20 miles on their foraging trips and can swim as far as 100 miles round-trip. But much of the time they’re fishing close to the colony. “They work their socks off to fish,” Sherley said.
Lately they’ve had to work much harder. The preferred prey of African penguins—anchovies and sardines—has been disappearing in much of the penguin’s range. The fish have moved some 250 miles to the southeast. Bound to their nesting colonies, the penguins cannot follow them. Studies by Robert Crawford of South Africa’s Department of Environmental Affairs and Tourism show that the breeding success and the survivability of these penguins are directly connected to the availability of anchovies and sardines.
What has caused the fish to move has proved elusive. “I suspect a suite of factors,” Crawford said. “That includes environmental change. There’s plenty of evidence of change in the Benguela Current.” The current carries frigid, nutrient-rich waters from Antarctica, and it has warmed at the southern and northern edges and shifted to the east.
Another problem may be overfishing. Over the past six decades, South African fishermen have harvested about 400,000 tons of sardines annually in the purse seine fishery. One study puts the local fish “carrying capacity” (a measure of potential population) at only 10 to 20 percent of what it was a century ago.
The South African government recently started restricting fishing temporarily in areas near breeding colonies. It’s an experiment to see whether protecting marine areas can improve seabird populations. “A few years ago, there was no consideration of the impact of the fishery on seabirds,” says Sherley. “Today, the possibility that the fishery may be contributing to the declines is being taken seriously.”
When I came to Robben Island, I expected to be won over by the penguins. They did not disappoint. I could watch them endlessly. Perhaps their charm derives from their similarity to us. More than any other bird, they seem such comical little versions of ourselves. “We laughed at the colony of penguins,” Mandela recalled in his autobiography, Long Walk to Freedom, “which resembled a brigade of clumsy flat-footed soldiers” marching across the beach.
Although I knew African penguins were in decline, I did not expect to hear such open talk among biologists about extinction. Penguins are improbable birds. None of us would have imagined such a creature if we had not seen one. But it’s even more unthinkable that we might lose them.
One morning on the island, we found three chicks that were clearly emaciated, their breastbones protruding from their white chests. Two were nest-mates, and little; the third was older, partially fledged. Sherley decided they had to be rescued. He caught them, put them all in a box with air holes and took them back to the research station. There he gave each an emergency tube feeding. In the afternoon, the chicks took the ferry to Cape Town, where they were met by people from the Southern African Foundation for the Conservation of Coastal Birds. They specialize in rehabilitating and releasing seabirds.