For mobility and action there is little to beat feather as a winging material and streamers, as well as feather-winged patterns, are extremely effective on many types of water. Although cock hackles were once the most commonly-used material, they have been almost entirely superceded by marabou. This soft, ultra-mobile, feather is now used to produce the wings and tails on a large number of patterns for reservoirs and small stillwaters, because, combined with a weighted body or head, it provides the fly with an almost irresistible action.