Final answer:
The Endangered Species Act (ESA) is the legislation that makes it illegal to bring certain parrot species to the U.S. to be sold as pets, offering protection for at-risk species and enforcement of management plans for their recovery.
Step-by-step explanation:
The legislation in the United States that makes it illegal to bring certain parrot species into the country for sale as pets is the Endangered Species Act (ESA). This Act was enacted in 1973 and requires the U.S. Fish & Wildlife Service to develop management plans for the protection and population recovery of listed at-risk species. While CITES regulates the international transportation of endangered species, it is the ESA that provides protection within U.S. borders, along with the Migratory Bird Treaty Act (MBTA), which protects over 800 bird species, including migratory birds and their parts from being disturbed or killed. These legislations are part of global efforts to protect species at risk of extinction and to combat illegal wildlife trade.