By Alison Ballance
Counting penguins is the main biodiversity task taking place on Antipodes Island. There are two kinds of penguins breeding on the island: erect-crested penguins, which breed only here and on the Bounty Islands, and rockhopper penguins, which breed on other subantarctic islands both in the New Zealand region and in the Indian and Atlantic oceans. Most populations of rockhopper penguins have undergone dramatic declines over the last fifty or so years, and it seems there might be a decline in the erect-crested penguin population as well.
Three years ago expedition leader Jo Hiscock, from DoC, led an expedition to establish a method of counting erect-crested penguins here, with the idea that it would be repeated every five years. However, the big slips that happened in January, and covered about 15% of the island, affected some of the penguin colonies, so it was decided to repeat the counts after just 3 years.
The colonies of penguins are scattered around the island, on rocky headlands, and in the case of the rockhoppers, some coastal sea caves and big boulder fields. The erect-crested penguins are the more numerous of the two species; they’re larger, and have short, bright yellow crests that bristle upwards and run like parallel railway tracks. The rockhoppers are smaller, and have longer yellow eyebrow crests that flop out to the side. They are only just starting to lay their eggs, while the erect-crested penguins are well into their breeding season. Both kinds of penguins have great characters: the erect-crested are the mellower of the two, while the wee rockhoppers always look a little demented, and are very feisty.
So what does counting thousands of penguins involve? The main equipment is a clicker counter, ear plugs, a can of biodegradable livestock marker, and a notebook.
It’s very difficult to accurately count large numbers of penguins nesting within a metre or less of each other, so the idea is that several people count at the same time; as long as their counts are within one or two penguins of each other, then that’s accurate enough. We actually counting nests, but the nests themselves might be nothing, or they might be a few pebbles so we’re just looking for the birds that are obviously incubating an egg: they have a telltale tummy bulge folding over their feet.
One person moves slowly through the colony, using the spray can to grid out counting areas, and then the counters stand at the edge of the area and sweep around, counting on their clicker. If there count is close they move onto the next area, if not they count again. This is the noisiest imaginable job, hence the ear plugs – the penguins are very defensive and protective, and start an ear splitting racket at any disturbance. But while it’s noisy, hard work that takes a lot of concentration, there are lots of compensations: the penguins are such characters, and there is always so much going on to watch, marvel and laugh at.
Kathryn, Jo and Alison spent 71/2 hours counting at the Orde Lees colony on Friday and Saturday. It was a 3 hour walk from the hut to our camp site, and another hour from the camp site down to the colony. We counted 6800 nests of erect-crested penguins, which is 1000 nests less than 3 years ago.
This is slightly concerning as this colony – the second largest on the island – was not affected by slips. Kathryn and Alison counted several small colonies at North Cape that had large slips come through and the penguins numbers there were about half what they were three years ago.
Tomorrow a team of 5 is heading to the largest penguin colonies on the island, a 5 hour walk way on the south coast. The counting there will take us about 3 days, and involve four nights camping, so there’ll be a slight hiatus in blogs until we are back.