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Canada Geese have largely given up migration entirely, because they =20 find it easier to graze on man-made lawns than to make an arduous =20 migration flight. This certainly does not indicate that the seasons =20 have ceased to occur. I have not been able to find a single convincing case of a migration =20 problem which would be caused by a change in a fraction of a degree. =20= Indeed, the severity of winters from year to years varies by much more =20= than that. There is much we do not understand about bird migration. There is =20 also much we have to discover about changes in bird population. Our =20 lack of complete knowledge is no reason for us uncritically to believe =20= every tendentious news story which comes along. On 15 Apr 2009, at 2:03 PM, Suzanne Townsend wrote: > = http://www.reuters.com/article/environmentNews/idUSTRE53D7G220090415?feedT= ype=3DRSS&feedName=3DenvironmentNews --Apple-Mail-5--463704088 Content-Type: text/html; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable <html><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; = -webkit-line-break: after-white-space; ">This is a good example of GW = hysteria by the mainstream media, in this case by the highly unreliable = Reuters. The article is pure speculation. It also ignores = the fact that the Earth was warmer just 7,000 years ago, and colder = during the Little Ice Age, and warblers seem to have made it through = those changes just fine.<div><br></div><div>The principle problem for = birds migrating between Europe and Africa, like those described in the = article, is loss of habitat (particularly in Africa). It is also = generally true that the bigger the bird, the more likely it is to be = pestered by humans: chased, shot, eaten, = &c.</div><div><br></div><div>The conversion of temperature into an = equivalent surface distance needed for migration assumes that = temperature is the main control of bird migration, which almost everyone = who has studied the subject knows is just not true. Food is the = main motive for migration, and the food needs vary according to species. = Birds will put up with a wide range of temperatures, if the food = is available. That is the reason so many feeder-species have moved = north, and now stay longer in the winter: if the food is adequate, they = will stay. It is one of the amazing things we observe: tiny little = creatures, out in the cold, with nothing but a thin layer of puffed-out = feathers to separate them from freezing =97 and yet they can handle = this, if they have enough food. They certainly can tolerate = temperature extremes much better than unprotected = humans.</div><div><br></div><div>Canada Geese have largely given up = migration entirely, because they find it easier to graze on man-made = lawns than to make an arduous migration flight. This certainly = does not indicate that the seasons have ceased to = occur.</div><div><br></div><div>I have not been able to find a single = convincing case of a migration problem which would be caused by a change = in a fraction of a degree. Indeed, the severity of winters from = year to years varies by much more than = that.</div><div><br></div><div>There is much we do not understand about = bird migration. There is also much we have to discover about = changes in bird population. Our lack of complete knowledge is no = reason for us uncritically to believe every tendentious news story which = comes along.</div><div><br></div><div><br><div><div>On 15 Apr 2009, at = 2:03 PM, Suzanne Townsend wrote:</div><br = class=3D"Apple-interchange-newline"><blockquote type=3D"cite"><a = href=3D"http://www.reuters.com/article/environmentNews/idUSTRE53D7G2200904= 15?feedType=3DRSS&feedName=3DenvironmentNews">http://www.reuters.com/a= rticle/environmentNews/idUSTRE53D7G220090415?feedType=3DRSS&feedName=3D= environmentNews</a></blockquote></div><br></div></body></html>= --Apple-Mail-5--463704088--
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