[mou] Brown-headed Cowbird - an unfortunate scapegoat
John Quinn IV
John Quinn IV <emperorjohniv@yahoo.com>
Tue, 11 Jul 2006 11:00:13 -0700 (PDT)
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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
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<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>
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