Additionally, some birds have the extra asset of two foveae ​ — areas of maximum optical resolution — ​ per eye, giving them a superior perception of distance and speed.
Selain itu, beberapa burung mempunyai aset ekstra berupa dua fovea ​ — area beresolusi optis maksimum ​ — per mata, memberi mereka keunggulan persepsi jarak dan kecepatan.