"The banning of DDT and other toxic pesticides also has led to the recovery of the and the in recent decades, according to the report. Over the same period, s, which give hunters and bird watchers a year’s access to National Wildlife Refuges for $15, have generated hundreds of millions of dollars in revenue, nearly all of which has gone to expanding wetland refuges. As a result, wetland bird populations have increased by nearly 60% since 1968, the report found. Species that have made particularly impressive recoveries include the , and ."