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Subject:Re: Blue Jay behavior question
From:Jesse Ellis <[log in to unmask]>
Reply-To:Jesse Ellis <[log in to unmask]>
Date:Tue, 1 Mar 2011 14:36:33 -0600
Content-Type:text/plain

Betsy-

Another factor to consider is predation, which confounds lots of questions
of behavioral energetics. My first thought is that perhaps your feeding
station now is a little more dangerous - more exposed, or there are more
known predators in the area, something like that, that leads to a higher
cost for the jays to sit and hack nuts. It may be more expeditious to dash
and cache than worry about calories.

Jesse Ellis
former corvidologist
Madison, WI

On Tue, Mar 1, 2011 at 10:42 AM, Laura Erickson <
chickadee.erickson@gmail.com> wrote:

> I think your questions are fascinating and worth examining
> experimentally, but there are a few more points to consider. Blue Jays
> probably started "weighing" food morsels not simply to get the most
> calories per trip but also because in the case of their most preferred
> natural food, acorns, the heavier ones are the ones least likely to
> contain a larval insect eating away at the contents. So selecting the
> heaviest ones is even more advantageous than it seems.
>
> Peanuts start rotting pretty quickly when stashed, and the process is
> quicker when they're not in the shell, so it's possible that over
> time, some jays figure out that it's best when caching peanuts to keep
> them in the shell. But those in your area may also be, as you note,
> simply trying to speed up the time they spend at the feeder.
>
> I doubt if anyone has worked out a definitive answer to your question.
> To start teasing out answers, you might try offering a small number of
> peanuts already shelled to see if the jays eat those on site or also
> carry them away for storing elsewhere.
>
> Best, Laura Erickson
>
>
> On Tue, Mar 1, 2011 at 10:27 AM, Betsy Beneke <birderbetsy@yahoo.com>
> wrote:
> > I started feeding blue jays peanuts in the shell many years ago, when I
> lived in
> > Detroit Lakes.  It was a Saturday morning ritual in the winter.  Start a
> pot of
> > coffee, fill the feeders, and throw a couple of handfuls of whole peanuts
> out on
> > the platform feeder.  I had two large picture windows in front of the
> kitchen
> > table from which to watch.  It was a very relaxing way to start my
> weekend.  I
> > LOVE watching behaviors in birds.
> >
> > The blue jays would fly into the yard the moment they heard my storm door
> shut.
> > There were 4-6 birds, I think.  Their "mode" was to fly to the feeder,
> pick up a
> > peanut, drop it, pick up another one, drop it - until they found the
> heaviest
> > one - then fly to a nearby branch, where they would hold the peanut
> between
> > their feet, poke a hole in one end of the shell, pull out the kernel, do
> the
> > same to the other side, and then let the shell fall to the ground.  This
> process
> > was repeated until they got several kernels in their mouth/throat, and
> then they
> > would fly off to the woods to stash them.  They would make repeated trips
> until
> > all the peanuts were gone and there was a pile of shells left in my
> yard.  All
> > the birds used this same process.  I understand that the heaviest peanuts
> are
> > chosen first because they have more nutrition per trip.  The wimpiest
> peanuts
> > were always the last to be chosen.
> >
> > I've been feeding the blue jays at Avon the same way this winter, but
> have
> > noticed that the jays here fly in, grab a peanut and then immediately fly
> off to
> > the woods with the whole thing.  They don't stop to pull out the kernels
> the way
> > the Detroit Lakes birds did.  I know that there are at least 7 different
> birds
> > who come in for the treats - maybe more.
> >
> > So my question for SOMEONE who knows more about this than me, is...why is
> the
> > feeding pattern different?  Is it a learned behavior within the local
> > population?  Or could it be that there are more birds here - more
> > competition/grappling for the goodies, so they zip in to grab what they
> can, and
> > then fly off to stash it safely away?
> >
> > I'd love to know the answer!
> >
> > Betsy Beneke
> > Avon, Stearns County
> >
> >
> >
> >
> > ----
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> > Archives: http://lists.umn.edu/archives/mou-net.html
> >
>
>
>
> --
> Laura Erickson
>
> For the love, understanding, and protection of birds
>
> There is symbolic as well as actual beauty in the migration of birds.
> There is something infinitely healing in the repeated refrains of
> nature--the assurance that dawn comes after night, and spring after
> the winter.
>
>             --Rachel Carson
>
> Please consider the environment before printing this e-mail.
>
> ----
> Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net
> Archives: http://lists.umn.edu/archives/mou-net.html
>



-- 
Jesse Ellis
Post-doctoral Researcher
Dept. of Zoology
University of Wisconsin - Madison
Madison, Dane Co, WI

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