SPATIAL MEMORY IN RUFOUS HUMMINGBIRDS (SELASPHORUS-RUFUS) - A FIELD-TEST

The spatial memory abilities of free-ranging rufous hummingbirds were tested in an ''open-field'' analogue of a radial maze. Eight artificial ''flowers'' filled with sucrose solution and arranged in a circle were placed within each bird's feeding territory. The birds were given two types of trial: in ''free'' trials, birds could choose which four of eight flowers to feed from before leaving the array; in ''forced'' trials, the experimenter presented birds with four flowers. Memory performance was assessed by observing the ability of the birds to avoid the emptied flowers on the return visit. On both types of trials, hummingbirds were able to avoid visiting the previously emptied flowers for retention intervals ranging from a few minutes to over an hour. Demonstration of good memory performance in free-ranging, nondeprived animals has both ethical and logistical implications for future studies on animal memory. In addition, such studies offer an ideal opportunity to test what and how well animals remember in their natural environment.