Changes in nectar concentration: how quickly do whitebellied sunbirds (Cinnyris talatala) adjust feeding patterns and food intake?

摘要: Nectarivorous birds encounter varying nectar concentrations while foraging on different food plants and must adjust their consumption to maintain constant energy intake. We determined how rapidly captive whitebellied sunbirds (Cinnyris talatala) volumetric intake feeding patterns after changes in diet concentration. On four consecutive days, were fed sucrose diets alternating between a standard of 16% w/w test 2.5, 8.5, 16 or 30% w/w, respectively, for 1.5 h periods. Feeding events recorded with an infrared photo-detection system body mass monitored continuously by electronic balances interfaced computer. Generally, demonstrated measurable increase frequency within 10 min decrease However, individuals responded differently the most dilute (2.5%): increased intake, others stopped short while, appearing dislike this diet. Furthermore, number duration first 5 switch from 2.5% back 16%, as attempted compensate previous reduced sugar Daily was lower when alternated 2.5 than other but able mass, presumably through behavioural adjustments.