PLAYING HIDE AND TWEET
Ground-nesting birds such as nightjars, plovers and coursers are famous for blending in with their surroundings to the point of invisibility. But new research shows how sophisticated their pattern-matching abilities are.
All nightjars look uncannily like a forest floor. But they don’t all look like the same patch of forest floor. “Each individual bird looks a little bit different, and we have shown that they can act individually,” says Martin Stevens of the University of Exeter.
Stevens’ team found that individual birds choose to hunker down on patches that best match their own particular markings. And they don’t align just their plumage – they also select a nest-site that provides the best camouflage for their eggs.
It’s not yet known how they do it. “It could be that somehow they ‘know’ what they look like and act accordingly,” says Stevens. “They may look at themselves, their eggs and the background and judge whether it’s a good place to nest, or learn over time about what kinds of places their eggs escape being eaten.”
The pennant-winged nightjar is a master of disguise.