An anvian visual perspective on color differences in females Sporophila seedeaters (Aves, Passeriformes)

PILAR BENITES; PABLO L. TUBARO; DARÍO A. LIJTMAER; MUIR D. EATON; STEPHEN C. LOUGHEED

Cornell University, Ithaca, New York, USA

Congreso; 12th International Behavioral Ecology Congress (ISBE 2008); 2008

International Society of Behavioral Ecology

An avian visual perspective on plumage color differences among females of Sporophila seedeaters (Aves, Passeriformes) PILAR BENITES (1), PABLO L. TUBARO (1), DARIO A. LIJTMAER (1), MUIR D. EATON (2) and STEPHEN C. LOUGHEED (3). (1) División Ornitología, Museo Argentino de Ciencias Naturales ¨Bernardino Rivadavia¨, Argentina; (2) Biodiversity Department, Drake University, USA; (3) Department of Biology, Queen´s University, Canada; pbenites@macn.gov.ar Females of a monophyletic group of Sporophila seedeaters, the “Capuchinos”, have traditionally been considered visually identical between species, based on human assesment of color. To test the assumption of identical coloration among four species of this group, Sporophila hypoxantha, S. hypochroma, S. cinnamomea, and S. ruficollis, we analyzed reflectance spectra on seven patches (crown, nape, back, rump, throat, breast and belly) from 37 study skins deposited in the National Ornithology Collection of the Museo Argentino de Ciencias Naturales (MACN). We used an avian visual model that takes into account the particular properties of the avian eye, such as presence of four cones in the retina with sensitivity across UV-Visible light range. For all patches analyzed, differences in plumage coloration were found that largely exceeded the threshold for two colors to be discriminable to birds. We also performed a Discriminant Function Analysis (DFA), with the parameters from the avian visual model as predictor variables, to establish a method to define species based on their color proprieties. Short wavelength from back and crown best separated the four species (97% of correct classification through cross validation). The results of this study show there are differences in plumage coloration of females of these species that should be visually detectable to birds. These results have biological consequences, as these four species can be found in different combinations and grades of sympatry/syntopy in parts of their distribution. As such, plumage colors have the potential to play a role in species recognition.