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 <email@example.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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