Spectral transmittance of the ocular media of eight seabird species from two orders: Procellariiformes (petrels and shearwaters) and Suliformes (gannets and shags).

Many, but not all, bird taxa possess the ability to see ultraviolet (UV) light, but it is currently unclear the extent this ability exists among seabirds. Measuring retinal photoreceptor sensitivity presents many challenges, but the penetration of UV light through the ocular media (ocular transmittance) is a good proxy for UV vision. Here we document the ocular transmission of light wavelengths using spectrometry through the eyes of eight Procellariiform and Suliform seabird species found in Aotearoa New Zealand. We report that the eyes of most Procellariiformes, but not the Suliformes, can transmit UV wavelengths. Thus, there is the potential for those Procellariiformes to perceive UV. Both phylogeny and ecology could play a role in UV vision in seabirds and understanding the wavelengths that seabirds perceive can be crucial for conservation against visual threats.