Palm Tanager (Thraupis palmarum) Science Article 2
The sugar-tasting abilities of four species of tanagers and two species of manakins were tested. Three tanager species were able to detect differences in diets containing 8%, 10%, and 12% sugar. In pairwise choice trials, they preferred the diet highest in sugar. Neither species of manakin discriminated among the three diets. This apparent difference in tasting abilities of tanagers and manakins may be a result of their fruit-handling techniques.Tanagers crush fruits in their bills, thereby releasing juices onto their tongues.
DOUGLAS J. LEVEY, The Auk 104: 173-179