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Subject:

Definitive Answer on Grasshopper Sparrow Song

From:

JAMES WILSON

Reply-To:

JAMES WILSON

Date:

Mon, 25 Jun 2007 06:41:55 -0400

    Jason Guerard is now working at the Cape May Bird Observatory.  In a 
previous life, he worked for the U. of Md. and spent 3 summers at Chino 
Farms outside of Chesterton, studying, among other things, Grasshopper 
Sparrows.  Jason continues to monitor MDOsprey when he has a chance.  He 
tried to post the answer provided below about the Grasshopper's 'bubbly' 
song but was unable to do so, so he sent me the answer directly.  Many 
thanks, Jason

Jim Wilson
Queenstown

BEGIN  QUOTE ***********

Hi Jim and all,

  I just happened to be taking a break from the adult life and saw your
post about the alternate Grasshopper sparrow song.  To give a some
what more lengthy answer; yes, they will do this a lot.  The song is more
commonly referred to as the "warble" song.  In fact, most literature
indicates that we are as of yet to discover the "real' reason that the
males sing this song.  Most believe it has to do with being paired.
  Having spent a few years studying grasshopper sparrows just up the road 
from
you Jim, I have personally formulated that the song is both
territorial and reproductive in nature.  When I was working for UMD in
Chestertown one of the things we were trying to formulate answers to was 
this
very question.  While we never did (while I was there at least) come to a
solid scientific conclusion, my anecdotal conclusion was that only
paired males would sing the warble song.  Obviously, un-paired males sing
only the buzz song.  This was evidenced by a particular
grasshopper we named "crazy singer."  This particular bird had some
sort of issue (probably a brain issue) where he sang a song that sounded
nothing like a typical grasshopper buzz song.  Interestingly, when we
recorded the song and digitized, the spectrogram showed that all of the
typical "parts" of the song were there (the three or so introductory
notes and then the buzz) but in a disarranged order.  Well, as luck would
have it this bird returned to the same exact spot (most grasshopper
males return to the very territory, with in a few yards, that they held
the previous season) for a few years in a row.  For the first two years
he would only sing his version of the buzz song.  No one ever heard him
sing the warble song (well, I thought I did in year two but never was
able to hear it again or record and in science you need solid proof.)
  Then in the third year I finally observed and recorded him singing the
warble song!!!  Not only that we had visual proof that he was
feeding young.  We were even able to obtain proof that the young he
was feeding were his true progeny.  So to make a long story short it is
my conclusion that the buzz song is used for territory/mate attraction
and the warble song, territory/mate communication.  I don't rely on this
one example alone for my conclusions.  I was fortunate enough to spend
6-8 hours a day out in the grasslands for three or so summers.  When
you have 230 acres and up toward 100 territorial male grasshoppers to
keep track of you end up observing a thing or two.