Fig. 1. Representative reflectance spectra for the types of ornamental color exhibited by male house sparrows P. domesticus and brown-headed cowbirds M. ater. Data were collected following McGraw et al. (1999). Note the absence of discrete peaks in the ultraviolet portion of the spectrum (300-400nm) for all plumage types. Also note that we have described the spectral profile of iridescent cowbird plumage at only one angle (90° to the reading surface); the general height of the curve for this plumage region would be expected to vary, depending on the angle at which the feather is analyzed.