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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.