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California Jays, Their Storage and Recovery of Food, and Observations at One Nest

1945; Oxford University Press; Volume: 47; Issue: 5 Linguagem: Inglês

10.2307/1364099

1938-5129

Harold Michener, Josephine R. Michener,

Water Quality and Resources Studies

During the fall of 1943, two California Jays (Aphelocoma californica) were busy gathering English walnuts from a large tree on a lot adjacent to our home in Pasadena.They hid many of them in the deep ground cover of leaves on our lot ; some were hidden entire and others were opened and partly eaten, the remainder being stored.With the smaller pieces, and also with sunflower seeds and pieces of bread, the hiding was often accomplished by placing them directly in loose ground.When an object was to be hidden, it was held in the beak and thrust downward and forward under the leaves or into the ground.If the going was hard, the object was sometimes hammered with the closed beak or taken to another place.When hammering, the whole effort seemed to be directed definitely toward getting the object out of sight and not toward opening the nut or sunflower seed as stated by Amadon as a probability with the Florida Jay (Aphelocoma coerulescens) (Amer.Mus.Nov., No. 1252, 1944:3).After thrusting the object to an apparently satisfactory position a Jod of dirt, a rock, or a leaf, or more than one of these, was usually placed over it:The fact that, while raking leaves over a small part of the yard, we found 16 walnuts without any effort to look for them, substantiates the conclusion that large numbers were hidden by the jays, a conclusion already reached by observations of their considerable carrying and burying activities.Do jays recover the food that they.hide in this way?That they do not recover all of it was surprisingly evident one spring after the jays had had free access to the box of chicken feed which contained a liberal admixture of sunflower seeds.Sunflower plants came up all over the block.On the other hand even casual observations convince one that they recover a part of the food hidden, the amount probably depending to some extent upon their need to draw upon that supply.Also, observations make it easy to conclude that they remember, or know in some way, where at least some of the food has been hidden.During the winter, one, and probably both, ' of the two individuals mentioned above was seen to alight 0' ; an extensive pile of leaves, look around deliberately, take a few hops, throw aside a few leaves, look around again, take a few hops to another spot and again throw aside a few leaves.On one such occasion half a walnut was uncovered on the third trial, all three trials being made within a circle of three-foot diameter.On another occasion ten trials were made within a fifteen-foot circle before a nut was found.In another instance grass was being removed from a thick growth of low ground-cover plants.A jay came looking about among the plants four feet from the worker.It was thought to be looking for insects that had been disturbed.It picked up a eucalyptus seed pod and threw it aside.After repeating this three times within a small area, it picked up a part of a walnut in the shell, carried it about fifteen feet away and hid it in a pile of leaves.These jays opened the-English walnuts at various places in the yard, such as in the gutter of the garage roof or beside a garden hose lying on the ground, in which case the nut was placed on the ground and against the hose while the bird stood on the hose with one foot close on each side of the nut, holding the nut if need be.But the favorite cracking "anvil" was in the low, nearly horizontal branches of a shrub where three branches, two of them with forks, lay side by side in a manner that' formed a secure .,