How does a hummingbird see the world?

What the research shows

Two different kinds of study underpin what is known about hummingbird colour vision. Herrera et al. (2008) used electroretinography on the green-backed firecrown to map its photoreceptor sensitivities and found a cone peaking near 370 nm, which places hummingbirds among birds with true ultraviolet-sensitive cones rather than violet-sensitive ones, together with blue, green and red cones, the last near 560 nm. Receptor data alone cannot reveal how the signals are combined in the brain. Stoddard et al. (2020) supplied that evidence outdoors: wild broad-tailed hummingbirds discriminated nonspectral colours, including ultraviolet+red, ultraviolet+green, ultraviolet+yellow and purple.

Spatial detail has not been measured behaviourally. The best available figure is anatomical: Lisney et al. (2015) estimated about 5–6 cpd from the density of retinal ganglion cells, and the page uses 5.5 cpd, an estimate of roughly 20/110. Flicker fusion is estimated at 70–120 Hz because hovering and rapid flight demand fast vision, but it has not been pinned down, and the 120 Hz shown here is the top of that range. The limit of any screen is fundamental rather than technical: a nonspectral colour such as ultraviolet+red depends on a receptor the human viewer does not have, and a display with three primaries cannot create it. Boosted colour and a UV highlight can mark where such colours would occur, not show them.