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Re: Little skulls & cuckoos & cowbirds



At 09:07 AM 24/10/1999 -0700, you wrote:
>>>A previous post asked about symbiosis. [snip] In areas with low botfly
>infestation, the host
>rejects cowbird eggs and the cowbirds have mimetic colored eggs. Cool!>>

Well, maybe.  This was reported for Giant Cowbirds and oropendolas, their
hosts, on Barro Colorado Island, Panama.  Despite it being a much-repeated
tale it has never been verified or observed in other populations, and the
investigator who reported it has been suspected of stretching the truth a
little in reporting his results.  Doubts have been cast as to whether he
even did all the field work he reported doing.  More recent work in Panama
did not detect any evidence that Giant Cowbird eggs were mimetic, and a
further study failed to find any evidence that parasitism by Giant Cowbirds
was beneficial.  In short, I would be a trifle hesitant about this matter.
--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court                 
Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@home.com