Spectral reflectance (300nm to 700nm) of three begging-related traits of magpie nestlings: mouth (gape or palate), rictal flange and body skin at the beginning of the treatment with cyproheptadine (nestlings 2–4 days old). Values are means obtained from three replicates and corrected by a triangular smoothing (i.e. a floating mean with weights within a distance of 10nm)
