January 4, 2017 British Ecological Society (BES) ScienceDaily see full article here
Bigger isn’t always better — at least not in the bird kingdom, with new Deakin University research finding that the larger a bird’s bill the longer they spend trying to snuggle it in against the cold….the study examined the “backrest” behaviour of birds — where they turn their heads to the back and tuck their beaks underneath their feathers when they are resting.
“While people have long assumed that birds exhibited this behaviour to protect themselves against the cold, no one had actually rigorously studied it. We found that they were indeed using backrest to try to keep warm, because they do it more when it gets colder,” Dr Symonds said.
“But the surprising thing we discovered was that the birds with bigger bills used this behaviour more, and over noticeably longer periods. In fact, they continued to use the behaviour more even as the weather warmed.” The study looked at nine species of shorebirds ranging from the largest comparative beak size, 9.2cm, found on the red-necked avocet, to the smallest, 3.4cm, found on the masked lapwing….
Julia Ryeland, Michael A. Weston, Matthew R.E. Symonds. Bill size mediates behavioural thermoregulation in birds. Functional Ecology, 2016; DOI: 10.1111/1365-2435.12814