Tuesday, November 29, 2011

South Africa #9: Why Go to Dassen Island?

Penguin biologist Paul Leonard is in South Africa researching African penguins in the wild. The following is a report from the field. You can learn about the time he spent nursing abandoned chicks to health at a local rescue facility here

Dassen Island is rich in history and natural wonder. In the early 1900's Dassen, like many other southern African islands, was exploited for its resources. Various species of migratory birds have called them home. As a result, the islands had built up a vast layer of guano (bird droppings). Back then the seabird guano, or "white gold" was revered as a powerful fertilizer for crops. Many islands were strip-mined and countless breeding sites destroyed. What made Dassen unique was that on top of having large guano accumulations, it also had a huge population of African penguins. Penguin guano was not considered to be as good as the other seabirds guano, but the penguins produced another valuable product…Eggs.

Dassen in the 1900s
Penguin eggs were considered to be a delicacy and were in high demand. On Dassen, a retaining wall was built all around the island in order to keep the penguins from nesting in its interior. This made the nests easily accessible to the egg collectors. Roughly 600,000 eggs were harvested each year for many decades. People thought that penguins were like chickens and that they would supply endless numbers of eggs. That was not the case since it takes several years for a young penguin to become reproductively mature. The number of African penguins on the island began to drop. In the late 1960's, the egg collection was eventually banned thanks to local protests and campaigns.

Dassen today

Today, Dassen Island is still home to African penguins. However, the population is in trouble. Over the last 10 years there has been an estimated 20,000 penguins living here. In recent years that number has dropped to about 8,000 to 9,000 birds. I'm here to assist the island's stewards in assessing the health of this colony. We are conducting nest surveys, studying breeding conditions and attaching GPS data loggers to several individuals. The hope is that all of this data will help paint a picture of what the African penguin is coping with and what we can do to change it.

Follow the adventures of Paul's co-worker, Jo! Aquarium educator Jo Blasi is still on the mainland in South Africa learn about African penguins and raising abandoned chicks at SANCCOB through their chick bolstering project! Read about her experience on the Explorers Blog.

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