Sofia Zoo marmoset, and macaques. The predator sector houses big cats, bears and small predators, including lions, tigers, leopards, pumas and brown bears. In January 2011 the zoo received eight Humboldt penguins on loan from Germany. The penguins are on loan for about 18 months, after which they will be returned, with any offspring to stay at the zoo. The zoo has some 1,400 individual birds representing 192 species. Waterbirds are housed in a lake, and Imperial eagles, Griffon vultures, Egyptian vultures and buzzards in a large walk-through aviary. Other species of birds at the zoo include ostriches, Silver pheasants, peacocks, flamingos,
Phoenix Zoo animal husbandry and research projects for selected species that are in need of conservation efforts. In its first years, the zoo hosted a captive breeding program ("Operation Oryx") with the specific goal of reintroducing the almost extinct Arabian oryx to the wild. By the early 1990s this program was still one of only two programs (the other being the golden lion tamarin) to have gone through the full wilderness-zoo-wilderness sequence. Nine oryx had been caught or donated for the breeding program. However, two pairs were delayed, so the "World Herd" was started in Phoenix in 1963 with only five animals