Read the following paragraph.
Sometimes at night we see birds flying in groups. These birds which do not have permanent nestlings and join into small flocks and move from one region to other for food and shelter called as ‘Migration’ and such birds are called Migratory birds. During the rainy season most of the birds from far away places migrate to Kolleru and Pulicat lakes of our state. They build their nests on the trees in the nearby villages. Due to the cut down of trees, less number of birds are coming to here. Answer the following questions.
a) What are Migratory birds ? Why do they migrate one place to another?
b) What are the reasons for less number of birds migrating to India?
