An interesting article from the UC Berkeley News Center discusses the strategies that fox squirrels use when caching nuts.
A group of students at the University of California, under the direction of psychology graduate student Mikel Delgado, have been tracking 70 campus fox squirrels, mapping their territories, and studying the strategies that the squirrels use to find, hide, and retrieve different kinds of nuts. The students hope to determine how the squirrels determine the quality of each nut, and decide what amount of investment to put into that nut, whether to discard, eat immediately, or to cache the nut.
Like the video in my previous post, this article confirms that tree squirrels rely on much more than just their sense of smell to locate hidden nuts. According to Delgado, the squirrels use a combination of landmarks and spatial memory to narrow down the location to a specific area, while probably relying on smell only for the "final bit of searching."
The article includes a cute video of some of the UC campus fox squirrels hiding nuts:
This looks like some extremely interesting research that promises to shed some light on the intelligence of our squirrely friends!