Tub Nests for Canada Geese

Abstract

Since 1958, Canada geese (Branta canadensis) in Missouri have used elevated nesting sites where losses to floods and most mammalian predators are eliminated. Wash tubs mounted on pipe were acceptable nest sites. Optimum tub spacing in open marshes was probably about one nest site per acre, provided a suitable loafing site was available for the gander. There was no correlation between height of tub and loss of nests to predators, or to usage by nesting geese. Tubs were still serviceable after 9 years but shifting ice was a hazard to the supports. Use of tubs by other wildlife was negligible. The purpose of this paper is to report techniques used successfully in Missouri for installing elevated wash tubs as nesting sites for giant Canada geese (B. c. maxima). Most of the work was done at the Trimble Wildlife Area, Trimble, Clinton County, Missouri, where geese have nested successfully in tubs since 1958. Yocom (1952) reported the first management use of elevated wash tubs as nest sites for Canada geese. Craighead and Stockstad (1961:369) and Brakhage (1965:776) elaborated on their value in the elimination of nest losses to floods and most mammalian predation. At Trimble, most successfully nesting pairs used tub nests. From 1962 to 1965, 268 tub nests and 106 ground nests were under observation. Only 2 percent of the tub nests were destroyed by predators while 32 percent of the ground nests were lost. Elevated nest sites are considered of particular value during the 7to 10-day laying period when the nest is not attended. In Missouri, No. 2 round wash tubs were used as nesting platforms. Tubs were attached to trees, stumps, bipods or tripods of steel fence posts, four-legged stands constructed of angle iron, treated wood fence posts, and lengths of pipe. Where marsh bottoms were too soft or water depths too great to use driven supports, tubs were mounted on anchored rafts. Tubs mounted by each of these methods were readily used by nesting geese. The stand which provided most flexibility in location and the lowest labor and material costs was the pipe stand. Lengths of galvanized pipe 1 or 1% inches in diameter and 6 ft long were used. At Trimble, the marsh soil was firm enough to support a pipe driven about 2? ft deep, and water depths were generally less than /2 ft. A %-inch hole was drilled in the pipe to allow equalization of water to prevent bursting in freezing weather. The method used to fasten the tub to the pipe is illustrated in Fig. 1. It was not necessary for the tubs to be rigidly mounted; female geese tolerated some swaying and lurching of nesting tubs. Tubs were spaced 50 to 75 yards apart on a grid system. Although I am not clearly supported by research data, I believe that reasonably harmonious nesting can be achieved in open marsh habitat at a nest site density of one per acre, a 70-yard spacing. Geese frequently nest at greater densities, but territorial disputes result and productivity is depressed. To reduce friction between adjacent nesting pairs, each nest site should have nearby a dry loafing area for the gander (Brakhage 1965:755). If such a loafing site is not available, a territorial gander is likely to use the nearest nesting tub for this purpose and so prevent its use for nesting by other geese. 1 A Federal Aid to Wildlife Restoration Project, Surveys and Investigations Projects, Missouri 13-4.