Birds in our Lives: Global Legal Protection and Conservation Efforts
High buildings, communications towers, and other related structures have become another threat to birds. It is estimated that approximately 3.5 to 975 million birds a year die because of those structures just in North America. The main cause of their death is glass windows, which kill about 100-900 million birds a year. This is followed by hunting that kills more than 100 million birds, house cats (100 million), cars and other vehicles killing about 50-100 million birds, electric power lines affecting 174 million, and pesticides (67 million).
Other conservation methods include captive breeding, otherwise known as ex-situ conservation, which works on reintroducing species in captivity, i.e, zoos, breeding facilities with consequent releasing into the wild. Captive breeding techniques have been used for a long period of time to save species from extinction. For instance, the Mauritius kestrel’s population was only 4 individuals in 1974, but by 2006, the population grew to 800. Also, the California condors were decided to be taken into a captive breeding program after 1982, when their global population was just 23 individuals. Since 1992, the population has grown to 410 birds, and, in 2008, there were more California condors in the wild than in captivity for the first time since the beginning of the program.