I have bird feeders in my backyard oasis area. I feed thistle, sunflower, and mixed seed in various feeders. I also have a flat shelf feeder with peanuts that the blue jays and starlings (thanks, europe;)) love.
I have noticed that blue jays will pick up a peanut, drop it, then pick up another. They repeat this a few times, then fly off to eat their final choice. My gf mentioned that she has seen this behavior also. She assumed they were trying for the heaviest peanut (they are in-the-shell).
Anyone know about this avian feeding behavior? Has it been studied? Is there some mathematical formula that shows the most successful strategy for the jay to follow?
Aside: This morning there were more jays then usual. Turns out there were a bunch of recently fledged birds! Very nice to see over coffee.
I don’t know the answer to your question, but just thought I’d tell you about the jays I feed peanuts to. They’re western scrub jays, and I leave shelled unsalted peanuts out on my balcony and they love them. So do the crows. They will eat several then stuff their beaks with as many as they can fit and fly off. If the peanut is too big, they will rap it had on the balcony to break it up.
I do think your gf’s guess about them perhaps weighing them is probably correct.
Well, she was blessed equally with brains and beauty, so I would not be surprised. I just looked at some GIS pics of the western scrub jay. Cool looking bird!
I don’t know of any specific studies, but one site mentioned jays shaking unshelled peanuts to see if they have nuts in them or not. I certainly wouldn’t be at all surprised if jays were also trying to select the heaviest nuts.
It probably wouldn’t be too difficult to test this, by taking one nut out of some of the peanuts and then gluing the shells back together again, and seeing if the jays preferentially removed the heavier peanut shells. The problem would be to do it so the jays would not be able to distinguish the one-nut peanuts visually. You would have to open all the peanuts, then glue some of them back together intact with both nuts inside, while removing one (or both) nuts from the others before gluing them.
^I will discuss this with my gf. She was suggesting someything very similar. I did see a paper that dealt with learning in jays using color and peanuts. (Warning: PDF): elibrary.unm.edu/sora/Condor/files/issues/v079n03/p0384-p0386.pdf
Am I the only one thinking of the squirrel scene in Charlie and the Chocolate Factory?
Yes the scrub jays are awesome, they have so much personality and spunk. And they are larger than you would expect, and are such a bright beautiful blue. Here are a couple of blog entries about the birds that visit my feeder, with pics!
http://brookenelson.com/blog/2006/04/my-feathered-friends.html
http://brookenelson.com/blog/2006/05/crow-is-nuts-over-peanuts.html
nyctea scandiaca- great pics. I’ve been trying to respond in kind, but everytime I go to grab a camera, the birds take off.
Either that, or my dog comes trotting by with her tennis ball. Anyway, here are a coupla pics:
http://usera.imagecave.com/vetbridge/clematisfeeder.jpg
http://usera.imagecave.com/vetbridge/pepitanbirds.JPG
Finally, an explanation for why I have all these birds in my pants.
Let us hope, for your sake, they are not Nutcrackers
. . .or even woodpeckers!!!
Perhaps he’s now going to claim he has an Oxpecker* in there too.
*Along with Brown Boobies and Great Tits, one of my favorite bird names.
^ A stately looking bird. Considering he is on an ox, that is.
