--0-1268304213-1152640813=:7275 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable
I wanted to address misconceived idea of the cowbird as a negative prerss= ure before the discussion digressed further. First off the cowbird, like an= y other species has evolved to fill a niche in is environment. Obligate bro= od parasitism has evolved independently six times across five continents. A= pproximately one percent of avian species are documented obligate brood par= asites, or about 100 species among 5 families. The Brown-headed Cowbird, li= ke the Common Cuckoo, Shaft-tailed Whydah, and Black-headed Duck serve an i= mportant place in maintaining a healthy diversity among species.=20 Second an analysis of the impact a cowbird has on a species should consid= er common and at risk species separately. =20 Jim=E2=80=99s reference to the Kirtland=E2=80=99s Warbler excluded two im= portant points. While the rates of parasitism did drop after cowbird trappi= ng started, the Kirtland=E2=80=99s Warbler population only started to grow = after the Mack Lake Burn restored the pine habitat. Cowbird contol has prov= ided benefits for the Least Bell=E2=80=99s Vireo but we should not forget t= he reason these species are at risk in the first place - human expansion th= rough logging and agricultural development enabling the cowbird to reach th= e habitat of the warbler and vireo. =20 Cowbirds and their 220 hosts have developed an ecological balance. To sug= gest that the cowbird will decimate a commons species population ignores th= at fact that these species have interacted and survived for at least 15,000= years. If a chipping sparrow loses a clutch, this will not cause the decli= ne of the species.=20 In conclusion I would suggest to all members of the MOU listserve to take= the opportunity to observe one of the evolutionary wonders of avian behavi= or and consider what impacts you are having on your community and environme= nt. Before you criticize the cowbird think how your actions =E2=80=9Ccould = sway the balance of birds in a negative way=E2=80=9D=20 Thanks=20 John Quinn http://www.ulm.edu/~tolson/jquinn.html --0-1268304213-1152640813=:7275 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable <html><head><style type=3D"text/css"><!-- DIV {margin:0px} --></style></hea= d><body><div style=3D"font-family:times new roman, new york, times, serif;f= ont-size:12pt">=0A=0A<p class=3D"MsoNormal" style=3D"margin-bottom: 12pt;">= <span style=3D"font-size: 11pt;">I=0Awanted to address misconceived idea of= the cowbird as a negative prerssure before=0Athe discussion digressed furt= her. First off the cowbird, like any other species=0Ahas evolved to fill a = niche in is environment. Obligate brood parasitism has=0Aevolved independen= tly six times across five continents. Approximately one=0Apercent of avian = species are documented obligate brood parasites, or about 100=0Aspecies amo= ng 5 families. The Brown-headed Cowbird, like the Common Cuckoo, Shaft-tail= ed=0AWhydah, and Black-headed Duck serve an important place in maintaining = a healthy=0Adiversity among species. <o:p></o:p></span></p>=0A=0A<p class= =3D"MsoNormal" style=3D"margin-bottom: 12pt;"><span style=3D"font-size: 11p= t;">Second=0Aan analysis of the impact a cowbird has on a species should co= nsider common and=0Aat risk species separately. <span style=3D""> </sp= an><o:p></o:p></span></p>=0A=0A<p class=3D"MsoNormal" style=3D""><span styl= e=3D"font-size: 11pt;">Jim=E2=80=99s reference to the Kirtland=E2=80=99s Wa= rbler excluded two=0Aimportant points. While the rates of parasitism did dr= op after cowbird trapping=0Astarted, the Kirtland=E2=80=99s Warbler populat= ion only started to grow after the Mack Lake Burn=0Arestored the pine habit= at. Cowbird contol has provided benefits for the Least=0ABell=E2=80=99s Vir= eo but we should not forget the reason these species are at risk in the=0Af= irst place - human expansion through logging and agricultural development= =0Aenabling the cowbird to reach the habitat of the warbler and vireo.<o:p>= </o:p></span></p>=0A=0A<p class=3D"MsoNormal" style=3D""><span style=3D"fon= t-size: 11pt;"><o:p> </o:p></span></p>=0A=0A<p class=3D"MsoNormal" sty= le=3D"margin-bottom: 12pt;"><span style=3D"font-size: 11pt;">Cowbirds=0Aand= their 220 hosts have developed an ecological balance. To suggest that the= =0Acowbird will decimate a commons species population ignores that fact tha= t these=0Aspecies have interacted and survived for at least 15,000 years. I= f a chipping=0Asparrow loses a clutch, this will not cause the decline of t= he species. <o:p></o:p></span></p>=0A=0A<p class=3D"MsoNormal" style=3D"mar= gin-bottom: 12pt;"><span style=3D"font-size: 11pt;">In=0Aconclusion I would= suggest to all members of the MOU listserve to take the opportunity=0Ato o= bserve one of the evolutionary wonders of avian behavior and consider what= =0Aimpacts you are having on your community and environment. Before you cri= ticize the=0Acowbird think how your actions =E2=80=9Ccould sway the balance= of birds in a negative=0Away=E2=80=9D <o:p></o:p></span></p>=0A=0A<div>&nb= sp;Thanks <br>John Quinn<br></div><span><a target=3D"_blank" href=3D"http:/= /www.ulm.edu/%7Etolson/jquinn.html">http://www.ulm.edu/~tolson/jquinn.html<= /a></span><div><br></div></div></body></html> --0-1268304213-1152640813=:7275--
