Bird judgement

Nightjar's soft plumage and variegated coloring help it [blank] in with its surroundings, but it is the bird's own judgment in choosing the most sympathetic background that [blank] it a camouflage champion. "Each bird chooses where to nest [blank] on its specific patterns and colors, says camouflage researcher Martin Stevens, of the Centre for Ecology and Conservation at the University of Exeter in Cornwall. "Each individual bird looks a little bit different," he says. "This is not a species-level choice. Individual birds consistently sit in places that enhance their own unique markings, [blank] within a habitat and at a fine scale with regards to specific background sites."