Digestive parameters such as transit time and sugar assimilation are important in assessing nutrient utilization and deterrence may be related to post-ingestive effects involving these parameters. Nectar andmany fruits contain mainly sugars andwater, and avian consumers compensate for lowsugar content in their diet by increasing food intake: thismay also increase their intake of secondary metabolites. We investigated howthe alkaloid nicotine, naturally present in nectar of Nicotiana species, influences compensatory feeding and digestive performance of nectar-feeding birds.