Aplomado is an unusual Spanish word for "lead-colored", referring to the blue-grey areas of the plumage – an approximate English translation would be "plumbeous falcon".

[3] In adult birds, the upperparts are dark blue-grey, as is much of the head, with the usual falcon "moustache" contrasting sharply with the white throat and eyestripe.

Juvenile birds are very similar to adults, but their upperparts and belly band are blackish brown, the chest is streaked with black, the white on the head and breast is buffy, and the cinnamon on the underparts is paler, as are the feet.

Two other Falco species of the Americas, the merlin (F. columbarius) and the American kestrel (F. sparverius), seem to be closer to the Aplomado group than most other falcons, but the relationships of all these lineages are fairly enigmatic.

[5][6][7][8][9] The aplomado falcon's habitat is dry grasslands, savannahs, marshes, and, in Brazil, is commonly observed in some large cities, such as São Paulo.

[4] It also hunts at fields being burned, at which many birds of this species may gather; cooperation between individual aplomado falcons – usually members of a pair – has also been recorded.

[12] Documentary evidence for these naturally occurring birds was obtained in New Mexico in 1991, and sightings built steadily through that decade and the next, leading to successful fledging of three young in 2002.

The addition of nesting platforms to areas where Northern Aplomado Falcons Falco femoralis septentrionalis were reintroduced in South Texas improved the birds' productivity.

But in the Chihuahuan Desert locations of west Texas and southern New Mexico, the birds were never successful for an extended period of time, and The Peregrine Fund has now abandoned the reintroduction program.

American falconer Jim Nelson has written, "During the time of Shakespeare a new bird from the New World came upon the falconry scene in Spain, Portugal and France.