Hummingbird Feeders. Hummingbirds get the energy they need to maintain their astonishing metabolism primarily from flower nectar and the sugar water they find at feeders (here's the recipe). Think of them as miniature flycatchers, and sugar is just the fuel for getting their real nourishment.
afÂ·terÂ·imÂ·age. n. A visual image that persists after the visual stimulus causing it has ceased to act. Also called photogene. (ËÉËftÉrËÉªmÉªdÊ).
Abstract. The term visual adaptation describes the processes by which the visual system alters its operating properties in response to changes in the environment.