Robots and other high-tech tools battle invasive species

A helicopter pelts Guam's trees with poison-baited dead mice to fight the voracious brown tree snake. A special boat with giant winglike nets stuns and catches Asian carp in the U.S. Midwest. In the fight against alien animals that invade and overrun native species, the weird and wired wins. "Critters are smart -- they survive," said biologist Rob "Goose" Gosnell, head of U.S. Department of Agriculture's wildlife services in Guam, where brown tree snakes have gobbled up nearly all the native birds. "Trying to outsmart them is hard to do." Invasive species are plants and animals that thrive in areas where they don't naturally live, usually brought there by humans, either accidentally or intentionally.