Scotland

su ability of food to the arrival of predators, occur predict- data is that the hummingbirds learned that the specificably in time, and many animals are able to gauge the in-tervals between these events [e.g., 2, 8]. Timing abilities range in scale from animals varying activity levels ac-cording to events (such as the predictable onset of dawn and dusk) to anticipating the availability of food over shorter intervals. Other events, however, have refill times were 10 and 20 min. Whereas many studies indicate that animals anticipate rewards, and indeed many of the individual hummingbird PRPs were shorter than the refill rate, the birds ’ central tendency was to match or exceed the refill rate. Not one of the media