Food color preferences against a dark, textured background vary in relation to sex and age in house finches (Carpodacus mexicanus)

Butler, Michael W.; Behbahaninia, H.; Toomey, M. B.; McGraw, K. J.

Food color preferences against a dark, textured background vary in relation to sex and age in house finches (Carpodacus mexicanus)

Abstract

Many animals consume colorful foods, because bright coloration either enhances conspicuousness of food items or signals nutritional rewards. A comparatively under-studied aspect of food color preferences is the role of the background environment in shaping food detectability and choices. Previous work with house finches (Carpodacus mexicanus), for example, showed that individuals preferred red and green food items and avoided yellow ones. However, this study of desert, ground-feeding birds was done with seeds presented against an artificial white background that is unlikely to reflect natural conditions. Therefore, we performed a similar experiment, but quantified selection of colorful foods using a different visual environment that better mimicked natural conditions. We mixed dark, inedible distractor pellets (i.e., analogous to natural desert sand and rocks) with sunflower kernels that were colored red, green, yellow, or orange to test for differences in foraging patterns by sex, age, and expression of male plumage coloration in non-molting house finches. This food presentation resulted in yellow seeds having a significantly greater chromatic, but not achromatic, contrast with the background than red or green seeds. Under these conditions, all birds consumed yellow, and to a lesser extent red, seeds most often, and both adult males and females had a strong preference for yellow kernels; adult males also tended to prefer green kernels, but females tended not to prefer green kernels. Juveniles showed no significant preferences for any seed color, and adult male plumage coloration was not related to seed color preference. Therefore, in contrast to studies using different foraging environments, house finches tended to prefer yellow seeds, supporting models that suggest that visual background and contrast may be more important than color per se in visually mediated foraging decisions of birds. Moreover, the fact that adult males and females differed in food color preference has not been reported previously in songbirds.

Title	Food color preferences against a dark, textured background vary in relation to sex and age in house finches (Carpodacus mexicanus)
Creator	Butler, Michael W.
	Behbahaninia, H.
	Toomey, M. B.
	McGraw, K. J.
Publisher	Behaviour
Academic Department	Biology
Division	Natural Sciences
Organization	Lafayette College
Date Issued	2012
Date Available	2013-10-30T20:43:43Z
Type	Article
Language	English
Keyword	sex differences
	achromatic contrast
	chromatic contrast
	seeds
	foraging
	lighting environment
	food color
	plumage coloration
Bibliographic Citation	Behbahaninia, H., et al. (2012) "Food color preferences against a dark, textured background vary in relation to sex and age in house finches (Carpodacus mexicanus)." Behaviour 149 (1): 51-65.
Standard Identifier	Handle 10385/1355
Standard Identifier	DOI 10.1163/156853912X626141
Permalink	http://hdl.handle.net/10385/1355
Rights Statement	In Copyright
Rights Holders	Koninklijke Brill NV