Apparatus for Marking Wild Animals with Colored Dyes

Abstract

The males of Centrocercus, as of other plains-dwelling grouse such as Pedioecetes and Tympanuchus, congregate mornings and evenings in the breeding season on leks, usually in extremely barren situations, where they perform their nuptial dances. The leks may serve from four or five to a hundred or more males. Females in much smaller numbers come to the leks to select males and to breed with them there. The leks are situated in flat, open spaces with little or no cover which makes it necessary to use inconspicuous apparatus. A blind constructed on a lek the previous autumn was by the spring of 1941, apparently almost unnoticed by the birds. By entering this blind before daylight, prior to arrival of the grouse at the lek, the birds were apparently unaware of the observer's presence and some individuals later performed within 25 feet of the structure. Many birds displayed and some occasionally mated, within 100 feet of the blind. To mark the individuals with various colors of dyes seemed to afford a promising means for facilitating the observation of territorial and breeding behavior. As regards a suitable dye, experiments indicated that powdered commercial aniline dyes, soluble in water and alcohol, would be satisfactory. Bright blue, red, green, and yellow dyes were used, and by mixing them other colors such as purple and orange could easily be produced. No perceptible fading of colors was noted over two months when exposed to the bright desert sunlight or to rain, on feathers and other porous surfaces. Dye mixed only with water did not penetrate the feather structure but remained on the surface in