Such projects have produced some successes; one study estimated that conservation efforts saved 16 species of bird that would otherwise have gone extinct between 1994 and 2004, including the California condor and Norfolk parakeet.
En studie uppskattade att bevarande åtgärder hade räddat 16 fågelarter som annars skulle ha dött ut mellan 1994 och 2004, däribland kalifornisk kondor.