​​QUESTION:-
Explain Skein Formation in/of different birds in 100 to 120 words. 

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Dear student,

Skein formation in birds is also known as V formation due to the characteristic symmetric V- shaped flight formation during flights of birds, geese or ducks. The V formation improve the efficiency of flying birds especially over long routes. Especially migrating birds have to fly a very long distance without landing.
The skein formation allows them to spend lesser energy in order to fly. They are not flying on the same relative plain ,but each bird is at a lower altitude than the other. This allows them to take advantage of the upwash vortex fields created by the wings of the birds in front. This reduces the air resistance and the resulting drag.This helps them to fly efficiently.They rotate among themselves for the leader bird position to avoid exhaustion. 
This flight pattern allows each bird to see the leader bird. They can coordinate their flight path without crashing to each other or get lost. 
Regards