๐'๐ฆ๐ด๐ต ๐ถ๐ฏ๐ฆ ๐ฑ๐ฐ๐ถ๐ญ๐ฆ ๐ฆ๐ต ๐ถ๐ฏ ๐ค๐ข๐ฏ๐ข๐ณ๐ฅ. ๐๐ข ๐ฑ๐ฐ๐ถ๐ญ๐ฆ ๐ฅ๐ช๐ต ๐ข๐ถ ๐ค๐ข๐ฏ๐ข๐ณ๐ฅ : " ๐๐ณ๐ณ.... ๐๐ญ ๐ง๐ข๐ช๐ต ๐ถ๐ฏ ๐ง๐ณ๐ฐ๐ช๐ฅ ๐ฅ๐ฆ ๐ค๐ข๐ฏ๐ข๐ณ๐ฅ!" "๐'๐ฆ๐ฏ ๐ฑ๐ข๐ณ๐ญ๐ฆ ๐ฑ๐ข๐ด, ๐ซ'๐ข๐ช ๐ญ๐ข ๐ค๐ฉ๐ข๐ช๐ณ ๐ฅ๐ฆ ๐ฑ๐ฐ๐ถ๐ญ๐ฆ".
For the last ten days or so, Lake Geneva has been under the influence of a vast low-pressure system which has kept us in a mass of polar maritime air. In other words, it's freezing. The species (the Quail) has long since left to spend the winter where the weather is better. The expression actually refers to the verb cailler, which means "to freeze the blood", a situation that occurs at very low temperatures, by... ๐ณ๐ฟ๐ผ๐ถ๐ฑ ๐ฑ๐ฒ ๐ฐ๐ฎ๐ป๐ฎ๐ฟ๐ฑ!
In autumn, as the Quail flies away from our countryside, many waterfowl come to spend the winter on Lake Geneva. (๐๐ฐ๐ช๐ณ 60๐ด ๐ด๐ถ๐ณ ๐ญ๐ฆ๐ด ๐ฐ๐ช๐ด๐ฆ๐ข๐ถ๐น ๐ฉ๐ช๐ท๐ฆ๐ณ๐ฏ๐ข๐ฏ๐ต๐ด). ๐๐ผ๐บ๐บ๐ฒ๐ป๐ ๐ณ๐ผ๐ป๐-๐ถ๐น๐ ๐ฝ๐ผ๐๐ฟ ๐๐๐ฝ๐ฝ๐ผ๐ฟ๐๐ฒ๐ฟ ๐น๐ฒ ๐๐ฒ๐บ๐ฝ๐ ๐ด๐น๐ฎ๐ฐ๐ถ๐ฎ๐น? Birds have different metabolic mechanisms that enable them to cope with extreme cold.
The plumage is one of them. ๐๐ฒ๐ ๐ผ๐ถ๐๐ฒ๐ฎ๐๐ ๐ฝ๐ผ๐๐๐ฒฬ๐ฑ๐ฒ๐ป๐ ๐ฝ๐ฟ๐ถ๐ป๐ฐ๐ถ๐ฝ๐ฎ๐น๐ฒ๐บ๐ฒ๐ป๐ ๐ฑ๐ฒ๐๐ ๐๐๐ฝ๐ฒ๐ ๐ฑ๐ฒ ๐ฝ๐น๐๐บ๐ฒ๐: the ๐ฑ๐ฆ๐ฏ๐ฏ๐ฆ๐ด feathers comprising the ๐ณ๐ฆฬ๐ฎ๐ช๐จ๐ฆ๐ด (wing feathers) and ๐ณ๐ฆ๐ค๐ต๐ณ๐ช๐ค๐ฆ๐ด (tail feathers) are used for flight. They do not play a thermal role. The ๐ต๐ฆ๐ค๐ต๐ณ๐ช๐ค๐ฆ๐ด feathers are the bird's thermoregulatory coat. It consists of two layers: large feathers on the outside ๐ฟ๐ฒ๐ฐ๐ผ๐๐๐ฟ๐ฒ๐ป๐ ๐๐ป๐ฒ ๐ฐ๐ผ๐๐ฐ๐ต๐ฒ ๐ฑ๐ฒ ๐ฑ๐๐๐ฒ๐ (relatively thick in water birds) made up of small, light feathers.
Under the feathers is the animal's ๐น๐ฎ ๐ฝ๐ฒ๐ฎ๐. This has a dermis (part under the epidermis) that is often ๐ฐ๐ต๐ฎ๐ฟ๐ด๐ฒฬ ๐ฒ๐ป ๐ด๐ฟ๐ฎ๐ถ๐๐๐ฒ. As well as keeping warm, fat storage provides an energy resource when food is scarcer.
The thick coat of feathers covers most of the bird's body, giving it a ๐๐ฒ๐บ๐ฝ๐ฒฬ๐ฟ๐ฎ๐๐๐ฟ๐ฒ ๐ฐ๐ผ๐ฟ๐ฝ๐ผ๐ฟ๐ฒ๐น๐น๐ฒ ๐ฑ'๐ฒ๐ป๐๐ถ๐ฟ๐ผ๐ป ๐ฐ๐ญยฐ. However, careful observers will notice that the legs are not wrapped.
Heating its legs would cause a great loss of energy for the bird. I๐น ๐ฎ ๐ฑ๐ผ๐ป๐ฐ ๐ฑ๐ฒฬ๐๐ฒ๐น๐ผ๐ฝ๐ฝ๐ฒฬ ๐๐ป ๐บ๐ฒฬ๐ฐ๐ฎ๐ป๐ถ๐๐บ๐ฒ ๐ฑ'๐ฒฬ๐ฐ๐ต๐ฎ๐ป๐ด๐ฒ๐๐ฟ ๐ฑ๐ฒ ๐ฐ๐ต๐ฎ๐น๐ฒ๐๐ฟ ๐ฎฬ ๐ฐ๐ผ๐ป๐๐ฟ๐ฒ-๐ฐ๐ผ๐๐ฟ๐ฎ๐ป๐. The heat of the blood is transferred from the artery (warm blood) to the vein (cooled blood) before it passes into the legs. The blood continues to flow through the legs, but the heat is retained in the bird's body, deliberately leaving its feet cold.
This device reduces energy wastage by avoiding heating a poorly insulated part of the body. ๐๐น ๐ฎ ๐ฑ'๐ฎ๐ถ๐น๐น๐ฒ๐๐ฟ๐ ๐ถ๐ป๐๐ฝ๐ถ๐ฟ๐ฒฬ ๐น๐ฒ๐ ๐ต๐๐บ๐ฎ๐ถ๐ป๐ ๐ฝ๐ผ๐๐ฟ ๐น๐ฒ ๐ฐ๐ต๐ฎ๐๐ณ๐ณ๐ฎ๐ด๐ฒ ๐ฑ๐ฒ๐ ๐ฏ๐ฎฬ๐๐ถ๐บ๐ฒ๐ป๐๐ and is probably also the origin of the expression "a cold duck", as a contraction of "il fait un froid ร en geler les pattes d'un canard".
Another explanation is linked to duck hunting. In fact, ducks were hunted in autumn and winter, and consequently in cold weather, curdling the patient and immobile hunter who waited for his prey.
Photo credits :
Kai Taimsalu
Sources :
Cowb.be (2014), "Birds' adaptations to withstand the cold."
