. >> his name is karl campbell.ove for animals but cold-blooded in what he is willing to do to save them. i hear the cheap, the chirp. >> yes, there's one just up here. >> and he has brought me to this tiny haven to look for the one creature that inspired darwin's ideas more than any other. hey, what's up, buddy, i came a long way to see you. the floreana mockingbird. >> when darwin came here, he collect them with a stick. >> just whacked them with a stick? >> just whacked them with a stick. that's how naive they are. >> they didn't know to fear man yet. >> they didn't have fear of anything. >> /* >> they didn't have a fear of man? >> they didn't have a fear of anything. this is one of the world's rarest birds for sure. >> i will explain why this little guy is hanging on by a thread in just a minute. but to understand how karl plans to save then, we have to back up, hop over to isabella island and get to know these guys. galapagos is an old spanish word for tortoise. and for age, they were the plotting bulldozers of

karl campbell obviously can't use his goat snipers against rats, but park officials want him to use thosentire island with poison. how do you make sure you don't poison the pigs and the cows and farmers and tourists? >> the measures that need to be taken are simply to remove the potential pathway that the toxin may be able to get to them through bait. >> so, before raising the $20 million to pay for this plan, karl and park officials have to convince the farmers up this bumpy road to move all of their livestock and pets for months. farmers like claudio cruz. so it's corn, yucca. >> banana, papaya. >> since he's seen rats eat entire fields of corn, no one wants them dead more than claudio. but he has very reasonable worries. what if the government decides not to bring the cows back. what if the poison gets into the water? [ speaking in foreign language ] which is easier? sniping a quarter million goats? or poisoning a million rats on an island like this? or convincing the locals that these are good ideas? >> the more challenging part is working in partnership with communities, so that esse

eyeisland, and they have eaten the egg, and gone after the giant tortoise eggs as well but that guy, karl campbell of goats. >> and why do you call him the cold blooded killer? >> well he shot 200,000 goats from the air, and so we have reach ed reached a point in human evolution where we are forced to play god in deciding which animals have to die so these few can live. >> and you were mentioning this because you have encountering the tortoises here. >> yes, they are the size of the desk, and amaze, and what happens when the whalers a and the pie pirates were-- pirates were sailing, you can flip them upside down and they would eat the tortoise stew and they would then eat it and it is a fascinating study of the unintended consequences and how fast something can go. and darwin knew they were overhunt overhunted, but they brought a few back on the "beagle" and they were still hunted. >> and where next? >> we are going to an island to the greece where people live to be 100 at a staggering rate but now they are getting junk food and facebook, and now they are at risk. >> and now, i want to spin and yo