THE bright plumage that some male birds use to attract mates comes at a cost: the species is more likely to become extinct, at least locally.
Bright colours advertise fitness to potential female partners, but increase visibility to predators and demand extra nutrients such as carotenoids. These costs drive flashy “dichromatic” species such as the northern cardinal into local extinction 23 per cent more often than duller species. So say researchers at Colorado State University, Fort Collins, and the Pierre and Marie Curie University in Paris, who analysed 21 years’ worth of birdwatchers’ observations in North America.
The birds usually…
