Behavior of the Florida scrub-jay (Aphelocoma coerulescens) remains the principal research although other avian species and the gopher tortoise have also been studied in previous years. The overall aim is to compile a complete behavioral dossier (ethogram), an aim that has led to many in-depth specific studies along the way. As the project enters its third decade, emphasis has been placed on cognitive aspects of foraging and caching behavior.

Each individual scrub-jay buries thousands of acorns every fall. Many studies of other caching species have shown that captive birds can find food items that they hide, which fact demonstrates a memory but leaves certain ecologically relevant issues open. By marking individual acorns seen to be buried by individually color-banded scrub-jays, Douglas Kramer showed not only that the jays re-find their own caches, but moreover do it amidst caches of other individuals in the same area.

Do jays re-find their caches simply by digging at familiar sites when they are hungry, thus finding items more or less by surprise? Or, do the birds "understand" that the items have a physical existence apart from their perception of them? This "object permanence" issue was first raised by the great Swiss developmental psychologist Jean Piaget when observing his own children. If a child retrieves an item that he or she watches you hide, then the child must understand that the item continues to exist even when not visible - an understanding that develops by about one year of age. Hailman did a similar experiment with the scrub-jays, showing that most birds readily dug up a peanut-half they watched him bury. In one family, though, no individual dug up the item so perhaps not all birds learn object permanence readily.

Jays probably learn specific kinds of foraging sites partly by trial and error, but can they also learn from watching and interacting with experienced individuals? Peter Midford taught certain individuals to forage for peanut bits that he buried in the middle of a plastic ring laid on the sand (see photos, this page). Other birds learned from those taught, and adults remembered the context from one year to the next, although juveniles quickly forgot it. Midford also showed that the behavior could be transmitted from one jay family to another by dispersing birds, thus establishing a basis for possible foraging traditions.

Finally, the most difficult cognitive problem tested the jays’ abilities to recognize a transformed food item, an ability called "object invariance." Hailman allowed hand-tame individuals to extract the nut from half a peanut, and while the bird was still on his hand, turned over the empty shell. A few birds immediately "understood" that this is the same empty shell so did not try to peck it open or take it from Hailman’s hand. Most individuals, however, did try to open or remove the empty shell so had to learn the object invariance, which they did at varying rates. One scrub-jay never learned the object invariance even after many more trials than taken by the slowest learner.