AVIS-IBIS

Birds of Indian Subcontinent

Color, Size, and Location of Artificial Fruits Affect Sucrose Avoidance by Cedar Waxwings and European Starlings

Publication Type:Journal Article
Year of Publication:1995
Authors:Avery, ML, Decker, DG, Humphrey, JS, A. Hayes, A, Laukert, CC
Journal:The Auk
Volume:112
Issue:2
Date Published:1995
ISBN Number:00048038
Keywords:Bombycilla, Bombycilla cedrorum, Bombycilla garrulus, Bombycillidae, Garrulus, Sturnidae, Sturnus, Sturnus vulgaris
Abstract:Fruit choice by birds is affected by many factors, but the interactions between sensory and postingestive cues has received little experimental study. To evaluate how postingestive responses to fruit sugars relate to color and other visual cues, we offered individually caged Cedar Waxwings (Bombycilla cedrorum) and European Starlings (Sturnus vulgaris) artificial red and green fruits containing 12.8% (g/g) sucrose or hexose (1:1, glucose: fructose) sugars. In 1-h trials with 6-mm-diameter fruits, waxwings preferred hexose to sucrose fruits, regardless of color. Birds given only sucrose fruits ate more than other groups. With 11-mm fruits, patterns of consumption were the same, but clear preferences for hexose over sucrose showed only in 3-h trials. Waxwings given red-hexose and red-sucrose fruits or green-hexose and green-sucrose fruits in two-cup tests learned to prefer the hexose fruits from positional cues. Starlings that initially preferred green learned to prefer red-hexose over green-sucrose fruits after two 3-h trials. Similarly, starlings that initially preferred red learned to prefer green-hexose fruits when paired with red-sucrose fruits. These preferences persisted through three posttreatment trials when both red and green fruits had only hexose sugars. In contrast to Cedar Waxwings, starlings given all-sucrose fruits ate the least, and two of four birds in the all-sucrose group stopped eating fruits altogether. At the level tested, sucrose was a strong associative repellent for starlings, probably because of induced postingestional distress due to their inability to digest sucrose. In contrast, waxwings can digest sucrose, but appear unable to maintain positive energy balance feeding solely on high-sucrose fruits. Development of high-sucrose cultivars may alleviate depredation to fruit crops by sucrose-deficient species like the European Starling, as well as by inefficient sucrose-digesting species like the Cedar Waxwing.
URL:http://www.jstor.org/stable/4088731
Short Title:The Auk
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith