Pigments in hybrid, variant and melanic tanagers (birds)

Abstract

• 1.

  1. Rump feathers in parental and hybrid populations of Ramphocelus tanagers along an altitudinal cline varied from scarlet to lemon yellow. However, spectral and chromatographic data indicated the presence of only a single carotenoid pigment. Dilution and statistical tests indicate that the observable colors were a function of pigment concentration. Spectral differences may be correlated with a single peak (470 nm) in the absorbance curve.

• 2.

  2. In a color variant of R. passerinii the spectral and chromatographic data suggest only a difference in pigment concentration. In both cases, these results were unexpected when compared to previous studies on seasonal change and the pigmentation of genetic mutants.

• 3.

  3. Melanic mutant scarlet tanagers retained the feather structure typical of carotenoid-containing feathers.

• 4.

  4. These observations relate to other studies on the biochemistry, metabolic and genetic control of avian carotenoid pigments and to proposed relationships between feather structure and pigment content.