By Alwyn Scott NEW YORK (Reuters) – The U.S. government took a step on Monday toward opening the skies to aerial drones, authorizing six sites where unmanned aircraft can be tested for a variety of uses. The Federal Aviation Administration already had approved limited use of drones in the United States for law enforcement, surveillance, atmospheric research and other applications. Mondays decision will give companies, universities and others place to test much broader uses, such as crop spraying, catching exotic-animal poachers or delivering packages, as Amazon.com Inc recently suggested. It provides the platform for this research to be carried out on a very large scale across the country, FAA Administrator Michael Huerta told reporters.