Wednesday, October 15, 2008
They've arrived !
Nearby Torgerson Island has become a very busy place. The Adelie penguins have arrived to their rookery. Over the last weeks we have seen first two or three birds, then a few more and now, in these lengthening spring days, the whole population has come suddenly come ashore. Adelies are beautiful, about 30 inches tall, and more playful than the other penguins in the area. Their colonies are raucous places full of their loud braying calls and flipper waving. The staff down here refers to them as being the "three years old of the penguin world".
The males, about 300 of them, arrived first. This is a pretty small colony; in comparison, some colonies in the Ross Sea reguion support half a million penguins. These birds have spent the winter out on the sea ice, which is warmer than the land, and are coming back to their ancestral colony to breed and raise young. Their primary danger through the winter has been the leopard seal which can catch them as they fish for krill in the water or explode up through thin ice to nab them. After living though the dark winter and successfully avoiding the leopard seals, they have swum, walked and tobagganed 20 miles or more to get here.
A day after the males arrived, the females came ashore, swelling the population to about 600 birds.
Penguins are mostly monogamous, forming partnerships that last many seasons and so, within minutes of coming ashore, most of the females recognized and reunited with their mates from last year. Nonetheless, for those birds whose partners did not make it back to the rookery, or who have not reunited with their mate, there will be fierce breeding competition over the next few weeks.
Watching them on Torgerson, we saw that they had started collecting pebbles for their nests, probably choosing the same spots in the rookery that they had built in last year. In Adelies, like most penguins, the males start the nests first, and then, once they have attracted a mate, or their mate has joined them, the couple will work together to collect and pile up the small stones.
Once their nests are built, the females will lay two (or rarely three) eggs which the couple will take turns incubating. Field biologists are arriving on the next boat and they will have the pleasure of monitoring this colonythroughout the spring as the young hatch and are raised. I'll keep you posted !