The cold, harsh winters of cities like Chicago, New York, and Seattle are no match for the tiny monk parakeet. Native to several countries in South America, the bright green bird, also known as the Quaker parrot, is one of 25 parrot species once kept only as pets in the U.S. that are now thriving in the wild of 23 states.

While most have stuck to warm-weather states like California, Texas, and Florida, the monk parakeet doesn't seem concerned with dropping temperatures or frozen food sources.

"We think they're basically pre-adapted to survive in cold climates because they build their own nests and they can vary their diets so dramatically across the year," says Stephen Pruett-Jones, an ecologist at the University of