why bird do no fatigue during migration
Answers
Birds that nest in the Northern Hemisphere tend to migrate northward in the spring to take advantage of burgeoning insect populations, budding plants and an abundance of nesting locations. As winter approaches and the availability of insects and other food drops, the birds move south again.
YES.
Flying requires an extensive amount of energy.
Birds however have adapted themselves for the flight.
>They have furcula (wish bone) which provides them firmness for flight.
>They additionally have a keel (carina) for anchoring the flight muscles.
>They have a certain section of their vertebrates fused together for firmness.
>Muscles! Muscles in birds are very well developed, They amount of Red muscles and White muscles may vary from bird to bird. For example, an eagle stays longer in air or an Arctic tern has to fly continuously in order to complete her migration on time so the amount of red muscles are more than white which provide them with endurance. A sparrow on the other hand will have more of white muscles because she flies short distances and has to be quick to escape predators or grab food.
>Certain less useful parts in the birds have been dropped to lessen their weight and help them to fly for a longer duration. For example: The jaws do not have teeth in 'Neornithes'.
They also have a very short or a reduced rectum (part of intestines which stores feces until defecation). This is also the reason why they keep dropping stuff here and there.
>They have pneumatic bones (hollow bones, without bone marrow) again to reduce weight.
>Birds maintain a higher temperature than the mammals to keep their muscles working up and going during the flight.
>Birds have modification present as air sacsin their lungs. The air sacs enable them to respire more efficiently thus keeping up with the oxygen demand during flight