Why don't birds get lost on their long travel flights?Scientists haven't understood this qustion for many years.Now they are begining to know it.
Not long ago,experiments showed that birds can guide them during daylight hours in the sun.But what about them by night?Some night-flying birds are able to follow the stars in their flights.
One such bird had spent its lifetime in a cage and never flown in the sky.But it can use the stars to guide in its flight.Any change in the direction of the stars made a change in the direction of its flight.
What do they do when stars can't be seen?They find their way by such landmarks as mountains or rivers.But when it's too dark to see these,they can lose their direction.