Future of endangered African penguins
- Two African penguin chicks were born in a South African nature reserve, where conservationists have been working for years to induce reproduction of the endangered birds.
- The colony had been abandoned over 10 years ago after a caracal killed several penguins.
- On the other hand, encouraging new colonies in sites close to abundant food sources could help bring species back from the brink.
Christina Hagen, South Africa's BirdLife Penguin Conservation Fellow 'Pamela Isdell' and project leader, was on one of her regular monitoring visits to the De Hoop nature reserve site in South Africa's Western Cape province, when he noticed them.
“Looking closer, I realized it was a chick. As I continued to watch, another one joined them from under a rock where they had made their nest.”
Work began in earnest four years ago as part of a program to protect endangered African penguins (Spheniscus demersus) along the coast of South Africa.
The decline of Africa's only resident penguin species began in the 1800s. People harvested their eggs and guano, which had accumulated over centuries, to export as fertilizer. This left birds without places where they could dig burrows to protect themselves, their eggs and their chicks from heat and predators.
To make matters worse, over the past 30 years or so, climate change and commercial fishing have depleted supplies of anchovies and sardines, the penguin's main prey items, and prompted schools of fish to migrate elsewhere. The low survival rates of both adult and juvenile penguins in key breeding colonies on Dassen and Robben Islands are linked to sardine shortages off the western coast of South Africa, the researchers say.
Since 1989, the total African penguin population has declined by almost 65%. According to current estimates, there are now fewer than 10,000 breeding pairs in South Africa, an all-time low, and about 5,000 pairs in Namibia, Hagen said.
Penguins fitted with GPS tracking devices were filmed swimming to De Hoop all the way from Dassen Island at a distance of 400 kilometers (250 miles). They had to gain weight before their post-breeding moult, when they stay on land while they replace their plumage and lose half their body mass because they can't go to sea to feed.
However, breeding on dry land comes with risks. Penguins are extremely vulnerable to lethal attacks: caracals, dogs, cats, mongooses and even bees are reported to have killed the penguins.
Four years ago, long before there was any sign that the penguins wanted to return, Hagen and colleagues sealed off De Hoop's breeding site, located on a rocky outcrop, by erecting a 2.4-metre (7-8 ft) high wire fence. electrified top and bottom.
The fence was monitored 24 hours a day, while Hagen kept a constant eye on any possible invasion on his phone app. There was only one invasion, in 2019, by a leopard ( Panthera pardus ). But that was before the penguins returned, Hagen added, and the incident allowed her to locate a weak spot in the enclosure, which has since been strengthened.
A key tool in restoring De Hoop as a breeding site has been the release of juvenile penguins, over 140 since 2021. These are birds that had been abandoned as eggs or chicks and then hand-reared by SANCCOB in a specialist unit run by the foundation itself, in Cape Town.
A few months earlier, she and colleagues had excitedly discovered three adult penguins on the site. But there was no sign that they were nesting there.
Hagen credits the recent upgrade to a loudspeaker that broadcasts penguin calls almost continuously with the help of a minicomputer and solar-powered amplifier. In fact, he believes that the stronger transmission may have finally attracted the attention of penguins looking for a place to settle. The realistic concrete decoy penguins scattered around the headland are also likely to have played a role, giving them the impression that the site was already occupied.
The penguin breeding in the De Hoop reserve is excellent news, said Lorien Pichegru, interim director of the Institute of Coastal and Marine Research at Nelson Mandela University, who was not involved in De Hoop's project.
A 2018 study, which Pichegru co-authored with over a dozen other scientists, predicted that without early action to protect food supplies, African penguins could become functionally extinct, with fewer than 50 pairs along the west coast of South Africa by 2035.
Attracting penguins to breed in places with rich food supplies isn't the only way humans are intervening. Research is underway to perfect nest boxes that replicate old guano burrows to keep penguins cool and safe in a world where the climate is getting hotter and less predictable.
The next indicator, he added, will be an increasing number of breeding pairs each year, as has happened at Stony Point and Boulders Beach for the past 40 years.