Northern Bald Ibis: The quite distinctive Northern Bald Ibis ranks as one of the rarest and most endangered of all known migratory birds.
This ranking occurs because experts know of only 500 wild individuals remaining.
In addition, this creature remains the only species of ibis known to breed and nest along cliff ledges.
All other known ibises have a distinctly different habit since they make their nests in trees. The species also once possessed a significantly greater natural range.
While they once covered much of Europe, northern Africa, and the Middle East, they now occupy only a fraction of that range.
The IUCN lists them as Critically Endangered, due to their extremely limited population.
Conservation efforts continue, yet their numbers continue to decline. The primary causes include habitat loss and illegal hunting.