Field-of-view:

Hawks and other raptors are predatory birds that must locate prey from a distance. As such, hawks require sharp focus at great distance and can give up some field-of-view as a trade-off. The total field-of-view for hawks is about 280 degrees with around 40 degrees of binocular overlap (Mitkus et al., 2018).

Depth-of-field:

While hawks require long-distance vision while hunting, short-range vision is required to navigate through the tight branches in the forest while in flight. Hawk eyes have evolved to accommodate both scenarios with shallow depth-of-field over most of the field-of-view to perceive close obstacles, but high depth-of-field in the center (Mitkus et al., 2018).

Focal field:

Hawks and other raptors have evolved a unique strategy that allows them to utilize multiple vision abilities--instead of just one fovea they have two (Fite and Rosenfield-Wessels, 1975). The central fovea is packed with an incredibly high density of photoreceptors. Because rods take up less space, this central fovea contains almost no cones, rendering sight in this 2 degree arc of vision colorless, but crystal clear, and perhaps even somewhat magnified. The secondary fovea is focused downward, allowing the bird to scan for prey while in flight.

Spectral sensitivity:

Like other avians, hawks are tetrachromats, but do not possess as great a sensitivity to light in the ultraviolet frequency range.

Next: Songbird Vision