[obol] more on cowbirds

[Ann Chamberlain]

For those who are interested, here is an article about live-trapping 
cowbirds to protect the Kirtland's warbler.

As a grad students in Michigan in the 60's we spent a lot of time trying 
to find nests and removing the cowbirds.  I am really happy to see that 
the techniques used today are really helping the warblers.  I doubt we 
did much although we tried!  There has also been a very successful plan 
to keep the jack pine forests at the right age for the warblers.

http://www.michigan.gov/dnr/0,1607,7-153-10370_12145_12202-32591--,00.html

The best news is, cowbird parasitism on the Kirtland's warbler has 
dropped dramatically.  The singing males have increased from fewer than 
200 in the 70's to slightly more than 1300 in 2005. 

We also conducted a breeding bird census near Douglas Lake, probably one 
of the oldest on-going such census.  Several grad students did this 
census every year and the data accumulated.  I know the census was going 
on in the 50's (maybe earlier) and 60's and I hope it still is!  The 
site covered one square mile and had  a power line cut through on one 
side.   There we clearly saw the effect of creating "edges".  Cowbirds 
penetrated about 200 ft. into the site from sides that were not 
forested, but the warblers that nested inside that border were mostly 
safe from parasitism.

Ann outside Myrtle Creek