Diagnoses of hybrid hummingbirds (Aves : Trochilidae). 8. A provisional hypothesis for the hybrid origin of Zodalia glyceria (Gould, 1858)

Abstract

Zodalia glyceria (Gould, 1858), supposedly from the vicinity of Popayan, Colombia, is hypothesized to be a hybrid between Lesbia victoriae and Chalcostigma herrani, which are sympatric in shrublands and timberline ecotones in the Andes from southern Colombia to northern Peru. Those portions of the capital, spinal, and ventral feather tracts that exhibit green iridescence in the parental species are greenish-blue to purple in the hybrid, depending upon the angle of observation. For example, the dominant wavelength reflected from back plumage is much Shorter in the hybrid (505 nm) than in either of the parental species (561-576 nm). This color shift is thought to have been caused by a developmental aberrancy, possibly associated with hybridization, which affected melanin granules that produce iridescence in feather keratins, Rectricial measurements of the hybrid fall between the character means for L. victoriae and C. herrani whose tails differ markedly in shape.