Why do birds fly to other countries? Detailed answer

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Why do birds fly to other countries? Detailed answer

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Why do birds fly to other countries?

The main reason that birds occasionally take long distance flights is quite simple. Due to the winter cold, the amount of available food is so reduced that they face a real threat of starvation. Thus, if the birds want to survive, they are forced to fly to warmer climes.

Birds go on long-haul flights to be sure that the number of surviving individuals of their species (even despite the risk of being blown away by the wind) will be greater than when they remain wintering in cold climes. When the risk associated with migration outweighs the risk of wintering, the birds are sedentary. But in lapwings and song thrushes, none of the wintering methods has an advantage over others.

The start time of bird migration is determined by the weather, with wind direction and strength more important than temperature. Many birds regularly return to the same place from which they flew for the winter. Scientists have observed ringed birds flying over the same place at the same time for several years in a row. In conclusion, it remains to add that birds are able to navigate by the stars and the sun, but scientists have not yet established how they succeed.

Author: Likum A.

Random interesting fact from the Great Encyclopedia:

How does a snake inject its venom?

In poisonous snakes, one of the salivary glands produces a substance that is dangerous to the victim. This substance is snake venom. The venom of some snakes is so dangerous that it can kill an elephant. In others, this substance is not so toxic. They can only kill a small lizard. Only two hundred venomous snakes out of 412 known species are considered dangerous to humans. Two of them are African snakes: rattlesnake and flying. They have fangs in their mouths.

Fangs are two or three teeth, greatly enlarged and having a groove on one side. Just above the fangs there is an opening leading to a poison-producing gland. When a venomous snake bites, the venom enters the trough and flows through it into the wound made by the fang. The cobra has fangs at the front of its mouth, one on each side. In most cobras, the canine groove is covered, forming a tube. The venom gland is surrounded by muscles. When the snake bites, the muscles press on the gland. This entails the flow of poison into the gutter, and then through the fang into the victim.

A cobra can inject venom from a fang, just like a liquid from a syringe. It's a spitting cobra. She aims directly at the victim's eyes. Its jet reaches almost 2,5 meters and almost always causes blindness. Poisonous snakes have a very perfect venom delivery system. Their fangs are very long, but can fit into the mouth so that the mouth can close. When the mouth opens to bite, the jaw moves forward, carrying the fangs at the correct angle to the throat.

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