Ospreys are listed as a species of “Least Concern” by the International Union for Conservation of Nature and are now considered one of the quintessential success stories of the conservation movement. Osprey population numbers crashed in the 1960s and ‘70s, when pesticides like DDT bio-accumulated in individual birds and thinned their eggshells, causing startling rates of mortality. Along certain portions of the Eastern U.S. coast, for example, nearly 90 percent of breeding pairs suddenly disappeared. The species' dramatic decline was halted by pesticide bans throughout the U.S. and the construction of artificial nests in wetlands countrywide. Overall, according to the North American Breeding Bird Survey, their populations grew by 2.5 percent per year from 1966 to 2014.