In the summer of 1970, 648 (329 males and 319 females) hand-reared wild-strain mallards (Anas platyrhynchos) were banded and released at the Arrowwood National Wildlife Refuge, Edmunds, North Dakota. The females were also marked with numbered nasal saddles. Liberation was by the gentle release method, and no special effort was made to isolate or condition the ducklings prior to release. Ducklings were placed in an enclosed pond area at 25 to 45 days of age. Altogether, 627 (97 percent) ducklings reached flight age and dispersed gradually into the wild. All had left the release area by 25 November. First-year band recovery reports indicated that 68 (11 percent) of the birds were shot in 15 states. Their migration pattern was similar to that for immature wild mallards banded in North Dakota in 1970.Eighty-nine (33 percent) of a possible 270 marked females returned to Arrowwood Refuge during 1971. When consideration is given to assumed normal natural mortality and crippling loss, an estimated minimum of 43 percent of the surviving females returned to the release area. Returning birds not observed would raise this figure even higher. This potential homing rate is considerably higher than rates reported for other studies using various strains of mallards. Numerous observations of nests and broods indicated that breeding behavior and nesting success were similar to those of wild mallards in the area. The success of this release is attributed to the inherent capability of hand-reared, wild-strain mallards to revert to their wild behavior, and to the high survival to flight age and first fall migration afforded by the gentle release in a sanctuary area. Indications are that releases of this type under the described conditions can be used to increase the breeding population of mallards in a local area.
Additional publication details
High survival and homing rate of hand-reared wild-strain mallards