Why birds hide their head under the wing?
The plumage is not only one of the devices of birds to flight, but also the ability to adjust the body temperature. It creates an air layer between the external environment and body. In cold conditions, this air layer allows you to maintain heat, and in hot – it does not allow overheating. It can be compared with thermos.
Due to the fact that the beak is not covered with feathers, the greatest heat loss goes exactly through it. If we look at the bird in the thermal imager, against the background of the blue cool external layer of plumage clearly see bright red beaks.
It would seem not to freeze, the birds need to get dressed in feathers from the head to the legs, that is, from the beak to the paw. But the presence of feathers on the beak would hurt the birds to grab food, build nests and perform other functions. There are birds with an in general absent plumage on the head, for example turkey or American vultures. There is an exit. If physiology cannot cope with something – the behavior helps. That is why birds hide their head under the wing!
They proved this environmentality from the Australian University of Dikin. For six months, from winter by the summer, they tracked nine types of slices and found that in the cold period, birds hide the beak under the wing significantly longer. Moreover, it turned out that the duration with which they do it directly depends on the size of the beak. What it is more – the longer the bird has to keep it under the wing to keep warm. Scientists published their findings in 2017 in the Functional Ecology magazine.
However, the beak can not only cool, but also overheat. Poultry temperature is relatively stable, unlike the environment. If we look into the thermal imager when the ambient temperature is higher than the body temperature of the bird, we will see that the beak is colder than the surface of the plumage, heated by the rays of the sun. That is why birds hide the beak under the wing not only in winter, but also in the summer. Just reasons for such behavior are directly opposite.