Range |
Winkler et al., 80 million birds/year: Walsberg 319 - 638 birds/year
|
Organism |
Biosphere |
Reference |
Kevin J. Gaston & Tim M. Blackburn, How many birds are there? Biodiversity & Conservation, April 1997, Volume 6, Issue 4, pp 615–625 p.623 2nd paragraph |
Primary Source |
Winkler, K., Fall, B.A., Klicka, J.T., Parmelee, D.F. and Tordoff, H.B. (1991) The importance of avian collections and the need for continued collecting. Loon 63, 238-46 link AND Walsberg, G.E. (1994) The use of wild birds in research. Condor 96, 1119-20 link |
Method |
Abstract: "Here, [investigators] use a variety of methods to estimate the global number of individuals for a single taxon, birds." |
Comments |
P.623 2nd paragraph: "Such figures can be compared with estimated losses to a variety of other sources, although their accuracy is not readily determined: 1000 million migratory birds each year to hunting and trapping in the Mediterranean countries (BNID 116946), between 97.6 and 975.6 million birds each year to window strikes in the USA (Klem, 1990), 1.25 million
birds to strikes at communication towers and 57.2 million to road kills each year in the USA (Banks, 1979), and 80 million or 319 to 638 million per year to predation by domestic cats in the USA (primary sources). The annual trade in live wild birds is estimated to have been between 2 and 5 million in the 1980s (Thomsen et al., 1992)." Primary source Winkler et al. p.244 right column 3rd paragraph: "Churcher and Lawton (1989) examined a poorly understood source of bird death: the domestic cat. They found that at least 20 million birds a year are killed by Britain’s cats. If cats in the United States hunt as effectively, and if cat numbers correspond to human populations, then [investigators] might expect more than 80 million birds to be killed annually by domestic felines in the United States." Primary source Walsberg p.1119 left column top paragraph: "Among domesticated predators, the most notorious are the 58 million domestic cats in the U.S. A conservative estimate is that each annually kills an average of at least 5.5 birds (Churcher and Lawton 1987) totalling 319 million birds per year. The actual value is undoubtedly greater, as this estimate is based only on the number of captures observed by the cat’s owners. This probably underestimates the number killed by about one-half (George 1974), suggesting that these pets destroy approximately 638 million birds per year in the U.S." |
Entered by |
Uri M |
ID |
116947 |