Guano (Bird excreta)
Guano is the accumulated excrement or droppings of fish eating sea birds such as gannets, cormorants and pelicans. It has been used as a fertilizer. These sea birds populate some islands off the west coast of Peru, lower California and Africa. Their population strength may go upto 5, 600, 000 per square mile. They may consume 1000 tonnes of fish daily. Exports of guano from the Peruvian deposits began in 1810 and reached 50, 000 tons in 1856. The Government protects the seafowls and processes the guano which contains about 11 to 16% nitrogen, 8 to 12 % phosphoric acid and 2 to 3% potash. The fertilizing properties of the phosphoric acid and nitrogen contained in fish were not recognised until the guano became a stimulus to intensive agriculture. The real guano is found in vast stratified accretions on rainless islands off the coasts of Peru.
The animals contributing to our economy and welfare are known as beneficial animals. Many animals provide us with nutritious food like meat and milk, clothing materials like silk and wool and the luxurious items like pearls andcorals. The silk worms, the honey bees, the lac insects, fowls, fishes, prawns and crabs belong to this category.
Since time immemorial, human beings have used animals for food and other purposes. While some animals are very useful to mankind certain others cause loss to the economy of man. Though every organisms has its own im-portance in nature, some of them such as a few mammals, birds, fishes, prawns and insects have become valuable. Some pests are competitors of human be-ings for natural resources and food. Thus a study of economically important animals will always be useful.