Cues for orientation in hummingbird foraging: color and position

In this study we examined the relative influence of the color and position of food sources on the feeding patterns of hummingbirds. We studied ruby-throated hummingbirds (Archilochus colubns) in the field and rufous hummingbirds (Selasphorous rufus) in the laboratory. The field experiments demonstrated that the use of equally profitable feeders in arrays is more strongly influenced by position than by color. This suggests that hummingbirds learn and remember the locations of profitable food sources and return to them preferentially if the reward continues to be adequate. The laboratory experiments demonstrated that although hummingbirds learn quickly to return to a single profitable feeder in a linear array of unprofitable ones if it is marked by a consistent color cue, their learning is strongly influenced by position in the absence of color cues. This suggests that hummingbirds' spatial memory may be limited in resolution and that they may use visible landmarks to improve their performance. These results are consistent with the hypothesis that landmarks facilitate foragers' limited ability to learn and remember profitable locations in their environments.