Assertion: tern's oil droplet | /r/HasProperty | red
Facets:
Source sentences:
text: Like other seabirds that feed at the surface or dive for food, terns have red oil droplets in the cones of their retinas; birds that have to look through an air/water interface have more deeply coloured carotenoid pigments in the oil drops than other species.
text: Terns have red oil droplets in the cone cells of the retinas of their eyes.