Eclipse Plumage in Gallus

Apart from more or less complex morphological and physiological investigations, a remarkably simple test serves to distinguish pure junglefowl from domestic fowl or junglefowl × domestic fowl hybrids. The phenomenon involved has been known to ornithologists for some time (Beebe, 1918–1922; Delacour, 1951), but so far as the writer is aware, it has not been given recognition by other authors of published articles and textbooks in poultry science. Reference is had to the eclipse phase of junglefowl cocks, a manifestation lacking in all domestic fowl. Ornithologists are familiar with the circumstance that male birds of certain species alter plumage phenotype after spring nuptials. Such alteration involves an estival molt, and replacement of shed feathers by plumage of different, and usually more somber, hue. In the case of wild Gallus, estival molt is partial and not complete, being limited to the cephalocervical tract. Long, lanceolate, gaudy hackles are molted, and . . .