We all know that many birds cache food (especially seeds), but the behavioral research summarized in a recent Science News article has several striking examples that may be new to some of us.  The article by Susan Milius in the Feb. 14 issue is titled Where'd I Put That? and is available online at the Science News website.

Two examples follow:

To rule out some simplistic attempts to explain the retrieval abilities of Clark's Nutcrackers, Russell Balda constructed a large platform with 330 holes, each of which could hold a small cup of sand or a plug.  With the possible cache locations artificially constrained, the birds could not retrieve seeds by following the same hypothetical rules about where to look that they might have followed in deciding where to hide.  Quick retrieval required remembering the specific places where seeds had been hidden.  Of course the birds did not perform perfectly, but they did about twice as well as a graduate student who was given the same challenge.  I wish Balda had also tested the student with items as valuable to him/her as seeds are to a Clark's Nutcracker.  Future research, perhaps.

Nicola Clayton showed that Western scrub jays remember WHAT and WHEN as well as WHERE.  Preferred food items like worms and crickets are retrieved before humdrum nuts, but the birds learn not to bother retrieving preferred items old enough to have spoiled.  The birds do indeed learn from experience how long various items last, as Clayton showed by replacing fresh with spoiled items (and vice versa) when the birds were absent.  Birds kept away from the caching areas for various numbers of days would retrieve preferred items young enough to be still good and not bother retrieving preferred items old enough to have spoiled, even though whatever was "enough" in their experience had been manipulated.

The Science News article has somewhat more detail, other examples, and (in the online version) pointers to the original journal articles reporting the experiments.