Today is 19 Dec, and I’ve been at Cape Royds now for about 8 days. No longer do I need to view the penguins by way of the Royds PenguinCam (www.penguinscience.com). I can do it in person!
The colony, the southernmost penguin colony on Earth, is quiet now.It’s just single birds sitting on their nests, while their mates are foraging at sea. It’s all business, with few young,non-breeders poking their noses (beaks) into others’ affairs, trying to stake a claim, stealing rocks or the like.
When the mates return every few days, after a few calls to make sure about identities (“Happy Feet” was correct: penguins do have individual songs!), the bird on jumps off and the other quickly settles in. They don’t want the egg, or little chick to be exposed to either the cold temperature or to lurking skuas too long. And, yes, the first chicks hatched 3 days ago, hardly noticeable other than the egg shells laying shattered nearby. It’s been cold enough (-1.5C) that the parents don’t expose them for very long. In about a week or two, the young birds will begin to arrive and then the neighborhood peace will be shattered. That is convenient, because the young non-breeders claim territories around the breeding birds, and that forms a buffer against marauding skuas as more and more chicks hatch.
This season we are going really high-tech in our research. In McMurdo Sound, colleagues are deploying a Remotely Operated Vehicle through a grid of holes in the fast ice. This ROV, called SCINI, fits through holes only 30cm wide that are drilled through the ice. SCINI has sensors that quantify the abundance and distribution of penguin food: krill and small fish. The SCINI has a long fiber-optics cable that sends the information back to a computer in a tent. We move from hole to hole deploying SCINI as we go. We are quantifying the prey now before cracks begin to form in the ice to allow the penguins access. We’ll then keep monitoring to see how the prey respond to the penguins’ harassment. Once chicks get a little bigger, and parents start making daily foraging trips — rather than the 3-5 days now — we’ll attach instruments to the penguins to track them and measure their foraging behavior. You can see a penguin with such an instrument if you go to www.penguinscience.com and click on the link that takes you to the iRobot glider page.
That gets me to the next aspect of our high-tech. Yes, we have deployed a robot that flies itself through the ocean and quantifies prey as it goes, and yes you can read about it and see it’s tracks on that web page. The robot is in the open ocean off Cape Crozier, the colony on the opposite side of Ross Island. We are seeking to quantify the prey off there as the penguins from that huge colony, the largest Adélie Penguin colony in the world (280,000 breeding pairs), deplete the prey nearby (so we think) forcing them to forage farther and farther from home as the season passes. In any case, in past seasons we’ve observed this ever-farther foraging by these penguins, and iRobot we hope will confirm that it is due to prey depletion. In contrast, at the tiny Royds colony (only 2000 pairs), we’ve not observed signs of prey depletion by the penguins.
All this is to better understand the Ross Sea food web, especially before the toothfish extraction messes it up. We’ve already observed a spectacular increase in penguins in the last several years, and we think this is due to there being fewer toothfish to compete for food with the penguins. Both the toothfish and the penguins feed on the same prey, especially silverfish, a little semi-school-forming fish. So far this season, it appears that the penguins are feeding almost exclusively on fish, which is not usual at this time of season. The penguins should be feeding on krill. If there are more silverfish, which are the most important predator on krill around here, then there should be less krill. Aye-yae-yae, when we started this penguin project 15 years ago we thought we’d only be investigating penguin response to changes brought by climate change. Now it appears that the fishing industry is messing up the trends. Bums!
While some will say that we shouldn’t complain if fish extraction brings more penguins, it appears that there are now fewer toothfish-eating killer whales (Orcas) and that Weddell seals are finding it harder to find toothfish, or at least large ones. But that’s maybe a story for a later blog.