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A breeding bird survey monitors the status and trends of bird populations. Data from the survey are an important source for the range maps found in field guides. The North American Breeding Bird Survey is a joint project of the United States Geological Survey (USGS) and the Canadian Wildlife Service. The UK Breeding Bird Survey is administered by the British Trust for Ornithology, the Joint Nature Conservation Committee, and the Royal Society for the Protection of Birds. The results of the BBS are valuable in evaluating the increasing and decreasing range of bird population which can be a key point to bird conservation. The BBS was designed to provide a continent-wide perspective of population change.〔(【引用サイトリンク】 title=The North American Breeding Bird Survey )〕 ==History== The North American Breeding Bird Survey was launched in 1966 after the concept of a continental monitoring program for all breeding birds had been developed by Chandler Robbins and his associates from the Migratory Bird Population Station. The program was developed in Laurel, Maryland. In the first year of its existence there were nearly 600 surveys conducted in the east part of the Mississippi River. One year later, in 1967, the survey spread to the Great Plains states and by 1968 almost 2000 routes had been established across southern Canada and 48 American states. As more birders were finding out about this program, the activity of BBS kept on increasing. In the 1980s, Breeding Bird Survey included areas such as Yukon, Northwest Territories of Canada and Alaska. Moreover, the number of routes placed in a number of states has had increased. Nowadays, BBS counts approximately 3700 active routes in the United States and Canada. From all the BBS routes, approximately 2900 are surveyed on a regular basis, each year. The density of the routes varies greatly across the continent and the largest number of routes can be found in New England and Mid-Atlantic states, in which there are more skilled birders to study the behavior of birds. Many bird watchers participate in these surveys as they find the experience rewarding.〔(【引用サイトリンク】 title=Birds Breeding )〕 Currently, the BBS is planned to be expanded to parts of central and western North America as well as northern Mexico. The surveys conducted by BBS take place during the peak of the nesting season, June, or May in countries with warmer temperatures. The BBS routes are 24.5 miles long and there are 50 stops at every 0.5 mile along the route. Routes are randomly located in order to sample habitats that are representative of the entire region.〔 BBS data is quite difficult to analyze given that the survey does not produce a complete counting of the breeding bird populations but more like a relative abundance index. And yet, these surveys have proved to be of great value in studying the bird population trends. BBS data can also be used to produce continental-scale relative abundance maps.〔 When analyzed at larger scales, the relative abundance maps can offer a clear indication of the relative abundances of bird species that are observed by the BBS. However, maybe the most effective use of these surveys is the opportunity to analyze population change, even though they do not provide information on the factors that cause these changes in the population trends. The BTO/JNCC/RSPB Breeding Bird Survey (BBS) is a national project aimed at keeping track of changes in the breeding populations of widespread bird species in the UK.〔(【引用サイトリンク】 title=Introduction to the Breeding Bird Survey )〕 In the UK, there are over 3200 active routes and more than 3000 individuals involved in monitoring the population trends of more than 100 bird species. The program started in 1992, and after being tested for two years, it was officially launched. As of 1994 the BBS data has been successfully used by Governments and different non-Governmental organizations for bird conservation purposes. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Breeding bird survey」の詳細全文を読む スポンサード リンク
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