Hi Marilyn, Well, I don't see anything in this article that suggests any reason that cowbirds STARTED laying their eggs in other birds nests. We are talking about something that happened way back during the cowbird's evolutionary history here, tens or hundreds of thousands of years ago. So in fact we will never know exactly why the first cowbird female started the trend to parasitism. What your "expert" put forward was a theory of why the behavior might have been adaptive for the cowbird population, ie what advantages did the behavior offer the population.
It certainly is a plausible explanation, in my opinion. Who was the biologist in the radio piece by the way? Interesting topic Marie (currently in June Lake, California hence my recent absence from Cayugabirds-L...but..."I'll be back"!!!) Marie Read Wildlife Photography 452 Ringwood Road Freeville NY 13068 USA Phone 607-539-6608 e-mail m...@cornell.edu http://www.marieread.com ***NEW*** See my beautiful photo notecards: http://www.marieread.com/cpg/displayimage.php?album=478&pos=0 ________________________________________ From: bounce-37740256-5851...@list.cornell.edu [bounce-37740256-5851...@list.cornell.edu] On Behalf Of Geo Kloppel [geoklop...@gmail.com] Sent: Sunday, June 26, 2011 10:01 AM To: CAYUGABIRDS-L Subject: Re: [cayugabirds-l] Why cowbirds foster their eggs to other birds Hi Marilyn, This article from the Smithsonian National Zoo covers your question: http://nationalzoo.si.edu/scbi/migratorybirds/fact_sheets/default.cfm? fxsht=3 -Geo On Jun 26, 2011, at 9:06 AM, Marilyn Ray wrote: > Hello Birders, > > The other day I got into my car just as a show about birds was > ending on the car radio. I did not get to hear the name of the > "expert" who was telling the audience about why cowbirds started > leaving their eggs in the nests of other birds to hatch and raise > their young. The "expert" said that the practice had its origins > in the middle part of the country when cowbirds had traditionally > followed the roaming buffalo herds and did not have time to lay and > hatch their own eggs before the herd moved on and they had to follow. > > Could someone please tell me if this story is true? If so, what > was the food the birds got from following the buffalo that they > could not get elsewhere? > > Thanks, > Marilyn Ray -- Cayugabirds-L List Info: http://www.NortheastBirding.com/CayugabirdsWELCOME http://www.NortheastBirding.com/CayugabirdsRULES http://www.NortheastBirding.com/CayugabirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://email@example.com/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/Cayugabirds 3) http://birdingonthe.net/mailinglists/CAYU.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --