When and how are the seasonal migrations of birds
No wonder the people about the fast birds are saying: «flying boom» — the potential speed of the bird’s flight is impressive. Duck, for example, can fly at a speed of 90 km per hour. Surprised by the endurance of birds, some in extreme conditions, can fly without a rest day. However, such effort is an exception to most cases. During periods of seasonal flights of birds fly at your own measured pace, and the flights spend one hour per day.
It is noteworthy that some species of birds can fly only in the daytime, others at night and some are moving at any time of the day.
The frequency of the bird’s flight depends on the weather. In the spring, warm birds tend to quickly overcome the distance and to return home. If a cruise the experience is cold, the flock waits this time in the places with the best weather conditions. In the autumn decline in temperature provokes a reinforced flight of birds. If fall happy Sunny and warm days, the birds do not rush off the edge.
Ducks, geese and some other birds fly away to hibernate in a warm country, not all together, but in several waves. Start operations in August, following two or three waves of migration are in the first half of autumn, the last of the guests leave when the water in the lakes and rivers begins to freeze.
The number of migratory birds depends on the wind. The wind makes the flight easier and faster birds have to overcome kilometer distance.
Many birds fly in flocks, which helps in time to see the danger.
The pack may be from random flocks of birds, and may have a certain shape – a wedge or a line. The construction helps to keep power – birds do not face, flying at the same pace. Interestingly, the view that clineva form of the pack helps to overcome air resistance, is incorrect.
From the point of view of physics, the advantages of such shape of the pack is explained as follows. When the bird flies in the air is whirling movement, impede the flight of the other is about a flying bird. If birds fly in formation, then the order will save them from the whirling streams of other members of the pack. Noticing the enemy, saw his first bird gives the signal, and the flock responds in unison.
The main bird of the wedge assumes the greatest load: tracks the right way, adjusts the speed of the movement. Therefore, the change leading ducks.