MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
Subspecific and temporal variation in the structurally based coloration of the Ultramarine Grosbeak
BARREIRA, ANA S.; LIJTMAER, DARÍO A.; LOUGHEED, STEPHEN C.; TUBARO, PABLO L.
Cooper Ornithological Society
Año: 2007 vol. 109 p. 187 - 187
Ultramarine Grosbeaks (Cyanocompsa brissonii) have a striking sexual dichromatism, with males dark blue and females brown. There are two subspecies in Argentina: the larger-bodied C. b. argentina which is common in shrubs and semi-open areas, and the smaller C. b. sterea that inhabits forests. We measured reflectance spectra on six plumage patches from study skins to evaluate the possibility of color differences between males of both subspecies and temporal variation of plumage coloration. We found differences between subspecies in color brightness, hue, saturation and UV chroma in the plumage patches of more conspicuous coloration, which we believe could be related to ambient light differences between the environments in which each subspecies is present. We also documented temporal color variation, particularly a gradual decrease of UV reflectance and a gradual increase of hue after molting in some plumage patches, possibly attributable to feather wear.