Countryside Notes – April

FEATHERS
In these modern times not many people have ever plucked a bird but it is in fact quite interesting to do so. Feathers are complex structures. Being barbed they interlock, serve specific purposes and come in different shapes and sizes, even on the same bird. Like our finger nails they are made from a tough, flexible material known as keratin and new feathers grow surprisingly quickly.
Perhaps the first thing we notice about a bird is its plumage and this time of year they look their best. Some species are quite drab, others moderately colourful and some are truly spectacular, especially the feathers on a kingfisher, a swallow or the heads of cock pheasants and mallard drakes which shine iridescent when they catch the light. Even the humble starling can look magnificent when the sun is shining. Very often the female is quite dowdy compared with the cock but in some cases they look identical. Each year birds gradually moult in summer and grow a new set of feathers. Interestingly male ducks lose all their wing feathers at the same time and are unable to fly for a few weeks. Their colourful body feathers are replaced with brown ones so they look like females; this provides camouflage when they are vulnerable. The drakes then moult again, regaining their colour. This process is known as ‘eclipse’. Feathers provide insulation and it’s very important they are kept clean and serviceable. Some species do this by either dustbathing or bathing in water. Most have an oily preen gland at the base of the tail which they use afterwards to waterproof their feathers.
Obviously the large wing (remiges) and tail feathers (rectrices), also known as quills, are very important as an aid to flying. It is common practice to clip half the feathers on one wing of a chicken to prevent it flying out of its pen. The short feathers on the top of the wing are called coverts. The body is covered with contour feathers which overlap like roof tiles, large ones on the flanks and either side of the breast and smaller elsewhere. These can be raised to trap air beneath for insulation or lowered at will. Beneath this covering are filoplumes – sensory hair like feathers. Wildfowl, sea birds and gulls have an additional insulating layer of light, fluffy down beneath their feathers. Originally eiderdowns were stuffed with the down from eider ducks but most down is now imported from China, typically from birds killed for their meat. The bodies of pigeons, herons, bitterns and some species of parrots are covered with what is known as powder down or dander. This grows continuously and instead of being moulted the tips disintegrate into a powdery substance. These species have a reduced preen gland or none at all. Owls’ feathers are designed so that they can fly silently.
Another use birds’ find for their feathers is to line their nests. Geese and ducks pull out copious amounts of down to make theirs cosy.
Jill Mason

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