Ground Nesting Birds and Camouflage
Ground nesting birds are vulnerable to predation. Their colouring acts as camouflage and makes them difficult to see. You might presume that it has been evolution which has ensured that the birds are the perfect colour to merge in with their surroundings. But there is now evidence that birds actually choose their nesting sites to match their own colouring.
Scientists at Exeter and Cambridge Universities have studied nine hard-to-see ground nesting birds to discover the secrets of their concealment strategy. What they found was surprising. Individual birds choose the positions of their nests based on their own specific patterns and colours.
Each bird is an individual and looks a little different to the next. The study revealed that the birds are aware of their own colouring and choose places to sit which suit their own markings. They not only select the right habitat to blend in to, they can detect the perfect spot within that habitat.
How Do They Do It?
The research was carried out in Zambia. The project leader was Professor Martin Stevens, of the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall. He has explained that the scientists are not sure exactly how the birds manage to choose the right site.
"It could be that somehow they ‘know’ what they look like and act accordingly," added Professor 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."
We think about camouflage as a natural trait which has evolved over a great period of time. But it looks like camouflage is actually partly evolution and partly the behaviour of the individual animals.
It was the local community in Zambia whose expertise and knowledge of their region enabled the researchers to locate the brilliantly camouflaged nests that they studied.
Scientists from Cambridge University also found that Aegean wall lizards sit on rocks that are the best match for their individual colouring in order to reduce the risk of attack by birds when they are soaking in the sun’s rays to warm up.
Certain species of reptile such as chameleons are able to change their colouring almost instantly to match the background and avoid predators. Aegean lizards can’t do this but do have the ability to choose the right place to sit themselves. It isn’t known whether the lizards have genetically evolved to possess this skill or whether they learn it from personal experience or from other lizards.
There may be many more creatures which have the self-awareness to identify the places where they will merge into the background. Our knowledge of this behaviour is currently extremely limited. Doubtless there will be further research which will reveal yet more amazing secrets of nature. Birds never cease to be amazing!