91热爆

When spring arrives, male birds start singing to attract a partner and to tell other male birds to keep away. Once the birds partner up they start to build a nest. Different types of birds use different materials including twigs, straw, moss, spider web and feathers. While many children are hunting for chocolate eggs, the female birds are busy laying and sitting on the eggs. The eggs must be kept warm for the chicks to grow.

For some types of bird, the male bird takes turn in keeping the eggs warm as well. The eider duck female has to do it all by herself, sitting on the eggs for four weeks and not eating during the whole time. The birds must stay with the nests, even during the cold and wet weather. The babies hatch out just at the right time, when there is lots of food for them to eat. The blue tit catches the caterpillars that are eating the new leaves sprouted tree leaves. A baby blue tit can eat 100 caterpillars in a day, so the adult birds are very busy.