about 22 miles from mcmurdo is cape royds, where a penguin colony of about 2,000 breeding pairs live. has been studying this colony for 20 years. >> anthony: so you're tagging the young ones? >> david: right. >> anthony: do you follow them through their entire life? i mean essentially -- >> david: yeah, this year we've got a bunch of individuals that are 20 years old. >> anthony: why penguins, what brought you to penguins initially? >> david: well, this kind of penguin does everything with no secrets. if you ask the right question and you're creative enough they're going to give you the answer without a lot of guessing. what really interests me is the relationship of these penguins to the ocean and how they fit into the food web. during the '90s, small colonies like cape royds were increasing much faster than the large colonies where the competition for food was so intense. in the last ten years colonies started increasing again. we think it's because of the fishery of antarctic tooth fish. the tooth fish and the penguin eat the same prey. so now there are more fish available for the