Ultraviolet patterns can make window glass visible to birds,
thus preventing fatal collisions. However, it has now been shown that such
windows are not likely to work for all species, but only for birds like small
passerines, gulls and parrots, who have a special type of colour vision. For
birds of prey, geese, pigeons and crows, these patterns should be difficult to
detect. These conclusions appear today in an article by Olle Håstad and Anders
Ödeen in PeerJ.