Migratory and wintering birds are warm-blooded creatures with an average body temperature of about 41 ° C.
In the autumn season, one can observe how some birds group in flocks, leave their homes and fly to the regions with a warm climate. Representatives who migrate annually from nesting sites to wintering areas and always return are migratory birds. They make up a third of all birds on the planet.
Migratory birds in Russia are represented by a large group of wetland and waterfowl species.
Units and types
This group of birds includes seven orders, including more than a hundred species:
- loons;
- toadstools;
- ciconiiformes;
- Anseriformes;
- cowgirl;
- cranes;
- waders.
Some migratory birds are listed in the Red Book and hunting for them is prohibited in Russia. This list is quite large: black-throated and white-billed loon, individual species of herons, geese, cranes.
What makes birds migrate?
Each spring fills our forests, fields and ponds with a bird's hubbub. These are the migratory birds of Russia returning to their nesting sites.
Birds make their flights over the sea and land since ancient times, long before the appearance of people on Earth. Millions of years of the migration period contributed to the fact that the physiological and biological processes in many species were balanced with the environmental conditions of different geographical areas.
Many questions are related to migratory birds. How do they navigate day and night, covering thousands of kilometers? How can one explain their attachment to specific breeding sites? Why do chicks travel huge distances, flying for wintering to tropical areas, and how can they return next spring to the places where they were born?
There is no answer to the question of how migratory birds determine the duration of migrations.
Migrations are a response to climate change and other environmental factors, due to which birds are much easier than other vertebrates to expand their habitat. Each spring, for several weeks, migratory birds accurately repeat the path that their ancestors traveled for many thousands of years during the gradual resettlement and expansion of the range.
Birds are constantly searching for the most optimal habitats. They use physical mobility to better realize the biological desire of each species to produce offspring or survive. Birds nesting in the Arctic, for example, can feed the chicks around the clock, due to the onset of a polar day, which allows them to successfully breed offspring.
To establish the fact that waterfowl constantly return to a specific nesting site, allowed the mass banding of birds, which is now carried out systematically on all continents. According to these data, they judge the degree of constancy of nesting duck populations in a particular area, as well as the resettlement and migration of chicks.
However, under the influence of various factors that affect the state of the environment along the path of their movement, their location and number can vary significantly. For example, due to environmental degradation in the lower reaches of the Ob River in Tyumen due to oil exploration and destruction of bird habitats, they are gradually shifting to the south.
The main routes of seasonal migration connect Africa and Eurasia, Southeast Asia and Eurasia, Australia, as well as South and North America. Most often, birds fly the shortest distance, but sometimes this path is winding. For example, cranes deviate from the shortest distance to stop to rest. Migratory birds can be in flight both day and night. Quickly flying representatives (swallows and swifts) sometimes feed right on the fly, and fly in the daytime.
Wrens, cuckoos and other birds with a secretive way of life rest during the day and eat, and make flights at night.
Waterfowl and near-water birds travel at any time of the day.
Small birds overcome no more than 50 km in one hour. The speed of hawks reaches 50-60 km / h, and ducks - almost 95 km / h.
Birds fly from 30 to 300 km per day.
During the day, they are guided by the elements of the landscape and the sun, or by the magnetic field in cloudy weather.
At night, birds can determine the direction of their flight by the stars.