We assessed how individual foraging preferences and cognitive performance affect foraging bout interval and the flexibility of foraging behavior in the nectarivorous Green-backed Firecrown (Sephanoides sephaniodes). Our field experiment evaluated the ability of these hummingbirds to recall nectar-renewal rates in two groups of artificial flowers with the same nectar concentration in the absence of visual cues. In a second experiment, we assessed their ability to remember differences in nectar quality combined with different nectar-renewal intervals, given artificial flowers with identical visual cues. Our results indicate that Green-backed Firecrowns adjusted their foraging intervals according to nectar-renewal rates and, furthermore, that birds were able to recall nectar concentration as well as nectar-renewal rate. Individual differences in memory performance resulted in differences in energy intake. These results strongly suggest that individual preferences and individual cognitive performance could play a central role in energy intake and, therefore, in the probability of survival. Received 30 September 2009, accepted 27 October 2010.