Bird migration is triggered by seasonal temperatures and shortening days. Physiological changes in the birds also play a part, whereby the birds go into a feeding binge to build up fat reserves for the long flight.
The question is 'how do birds know where to go?'. Birds normally migrate in flocks, and the most important factor to come into play initially is that the adults teach the younger birds the route. Remembering that initial parental guidance is paramount, the four methods for navigation are visual orientation, using the sun as a compass, steering by the stars, and an inbuilt sense that allows birds to use geomagnetism.
Visual orientation, using landmarks, is a method used by birds that migrate in the daytime, as is the sun compass method.
Species that migrate during the night time use the celestial navigation method.
Geomagnetism, in which the birds use the earth's magnetic field as highways, is a method used by many migratory species.
It is probable that most species use more than one method simultaneously--there would be too many drawbacks in a single method.
Birds are said to fly to places were there is presence of water. So when birds migrate they have an aim to reach a place and are ultimately successful. thus we can conclude that they know to fly in the desired direction.
birds are in a v shape.
No!
Don't stop! They know when to carry on about migrating. Stop when you have no birds.
Turkeys are not migrating birds because they can not fly ant have enough fat in their bodys to survive the winter.
stork
Local flora and fauna
Migrating
Migrating birds normally do so on an annual basis. They fly somewhere to nest and raise a family, then fly back afterwards.
Local flora and fauna
bird of paradise
so they can stay warm for the winter.
If there's going to be, we wouldn't know yet would we? Yes and there was - angry birds seasons