A ground-breaking study not only confirms the assumption that camouflage protects animals from the clutches of predators, but it also offers insights into the most important aspects of camouflage.
The research by scientists from the Universities of Exeter and Cambridge investigated the camouflage of ground-nesting birds in Zambia, using sophisticated digital imaging to demonstrate how they would appear from the perspective of a predator.
Martin Stevens from Exeter University who, along with Claire Spottiswoode from the University of Cambridge, co-led the project said: "Despite such a long history of research, ours is the first study to directly show how the degree of camouflage an individual has, to the eyes of its predators, directly affects the likelihood of it being seen and eaten in the wild."
The team studied a variety of ground-nesting birds, whose eggs would stay in a fixed location throughout the month-long period needed for incubation. This allowed the scientists to accurately compare both the adult birds, and their eggs, to their chosen backgrounds, as well as monitor which nests had been found by predators such as banded mongooses, birds, and vervet monkeys.
The team used specially calibrated digital cameras and computer models of animal vision to view the nests as the predators might see them. This ranged from the sophisticated color vision of birds, which can see ultraviolet wavelengths, to the relatively poor color vision of mongooses, which only see blues and yellows.
The research shows that the eggs of species that flee the nest as predators approach, such as plovers and coursers, are more likely to survive to hatching if they match the background more closely when exposed to view by their fleeing parent. In nightjars, however, which conceal their eggs by remaining motionless over them when predators approach, it was the appearance of the adults that was most important for their survival: nightjars that match the background pattern are more likely to save their eggs from being eaten.