i'm jeffrey kofman for "nightline" in punta tombo, argentina. >> they have a tip about parenting, bythe means split time with the females, keeping the eggs warm. you have to love that. >>> when we come back, michelle obama's pledge to fight childhood obesity. how did her kids influence her call to action? robin roberts has the abc news exclusive. [ male announcer ] how do the editors of consumers digest determine if a car is a best buy? first, they drive it in the real world and put it through its paces. they rate its fit and finish and the amenities inside. they factor in purchase price and operating costs, fuel economy, and resale value. in short, they do what you do to test its quality. the consumers digest best buys from chevy. put them to your own test. and may the best car win. ♪ right now 1.2 million people are on sprint mobile broaand. 31 are streaming a sales conference from the road. 154 are tracking shipments on a train. 33 are iming on a ferry. and 1300 are secretly checking email on vacation. thas happening now. america's most dependable 3g network. bringing you the firs

jeffrey kofman, abc news, punta tombo, argentina. >> and you can see more of jeffrey's report and aller tonight on "nightline." >>> hope you have a good evening and hope you're back with us tomorrow night. we'll be right here. see you then. captioned by closed captioning services, inc. this is the "jeopardy!" college championship.

that is where abc's jeffrey kofman caught up with her. >> reporter: these penguins are just back from trip. >> they're coming back to feed their chicks. >> reporter: the newest members of the largest colony of magellanic penguins in the world. >> that's the greeting. hi, honey, i'm home. >> reporter: in the 27 years she's been coming here, university of washington biologist dee boersma has banded 60,000 penguins and she knows the most intimate things about them. >> some pairs have stayed together 16 years. that's really high fidelity. >> reporter: we're on the sparsely populated southern edge of south america, one of the most pristine places on the planet. yet even here, penguins are in peril from overfishing, oil spills, and yes, rising ocean temperatures. and who wore this? >> this guy right in here. >> reporter: using satellite tracking, boersma has discovered penguins that were swimming 100 miles to fill their bellies with fish 10 years ago are now traveling an extra 25 miles. why are they going further? >> the food's just not here. part of that is probably climate change. it chan