Macaws, the largest members of the parrot family, are so called because they feed on the fruit of macaw palms in their Amazon habitat. The blue and yellow macaw is often kept in captivity. Although their collection from the wild has posed a threat to their numbers in the past, breeding programs are largely successful. Macaws vary greatly in size. At 100 cm (39.4 in), the hyacinth macaw of Brazil and Bolivia is the largest parrot in the world. It is more than three times the size of the smallest macaw, the red-shouldered macaw, a 30 cm (12 in) bird of northeastern South America.