Đang chuẩn bị liên kết để tải về tài liệu:
Birds - Section 5 - Birds house

The pollution of our streams and rivers is known to all of us. Water, so essential to life, is becoming a carrier of death! Almost every stream, lake and river is polluted, and the outlook for the near future is dark. A recent survey made by the Department of Health, Education and Welfare disclosed that the nation's drinking water systems are unsanitary. | shelter the third requirement Your bird-attraction project will be complete when you provide shelter and nesting facilities. Most people regard shelter as the most important requirement as a matter of fact food and water are more effective means of attracting birds. But shelter and nesting facilities must be provided because birds will not stay unless they have a place to build their nests and raise their young. We have explained how the spreading out of cities over the countryside deforestation and the drainage of swamps have curtailed the natural supply of food for birds. These same factors have reduced the shelter available to them. Their cover has been further shrunk by our clean pastures and forests with the old dead trees cut down brush 115 destroyed and growth along fences removed. Any manmade devices that will help to replace the birds dwindling supply of natural shelter will be a distinct benefit to them. Successful bird attraction requires an adequate number of the right kind of birdhouses. Birdhouses must be built for specific types of birds not just for birds in general and they must be correctly located and maintained. The construction of birdhouses offers a dual pleasure first the enjoyment of making them second the adventure of attracting and sheltering birds with them. know the birds you want to attract It is common knowledge that wrens will build a nest in almost any type of shelter an old tin can a shoe or a flowerpot. This fact has led many people to believe that all birds are no more selective in their choice of a shelter. This impression is far from the truth. Birds as a rule are very particular about where their nests are built and how they are made. For this reason you must plan a house for a specific bird making sure that it is the correct size has the proper opening and is placed at a predetermined height above the ground. The birdhouses described in this book follow these specifications and in building them you can be assured that they .