Adaptation of birds to the seasons
By how they adjust to the seasons, birds divide into three groups. Resident birds stay in one place all year: tit, collared dove, rock dove, chukar, pheasant, house sparrow, mynah. Some store food in summer: the tit hides seeds and insects in bark cracks and eats them in winter. Nomadic birds (rook, hooded crow, jackdaw, starling) move in flocks to places with less snow and more food when cold arrives. Migratory birds fly in autumn from cold or temperate climates to warm countries and winter there; they gather in flocks before leaving. Swallows, nightingales, orioles and storks leave in late summer because insects disappear; ducks, geese and swans leave in late autumn when the water freezes. They take the same route each year. Migration is an adaptation to the seasonal change of climate: birds of northern and middle zones nest and feed chicks in the warm period and leave when food gets scarce; in spring the breeding instinct brings them home. Shorter day length is the signal for autumn departure. Birds find their way by the sun and, at night, the stars; some also sense the Earth’s magnetic field. To learn wintering places, routes and lifespan, birds are ringed: licensed specialists put a light ring with an address on the leg. If a ringed bird is found, an adult helps write down the number and address on the ring and reports it to that address (a live bird is released); this method showed that Central Asian storks winter in India and European storks in tropical Africa.
Observation diary: for 2 weeks record the birds you see in your yard or garden (name, number, time). Decide which are resident and which migratory. Safety: watch birds from a distance and do not approach nests and chicks; wash your hands with soap after cleaning a bird feeder; do not touch a dead bird.