Last Call

Though simple in concept, actually knowing that something is extinct – that is, that the last individual of a species has disappeared – is incredibly difficult. Scientists rely on extensive and intensive surveys in the wild, and only if no solid evidence of life is found over an extended period of time will they conclude that the species is likely extinct. The primary forms of evidence used to confirm a bird species is still alive include capturing a live specimen, high-quality media captures (photographs, video or sound) that clearly include the bird's distinctive physical or vocalizing features , and genetic evidence (such as dropped feathers, unhatched eggshells, or active nesting materials, even trace cellular material that include a bird's specific DNA). If a bird species has gone ten or more years without any verifiable documentation, it is officially classified as "lost to science".

All of these species are most likely extinct, but unconfirmed sightings have occurred in the last few decades, leaving some hope that there might still be a small population surviving in remote areas.