Yuma County, Arizona
Yuma Clapper Rail
Table of Pesticide Active Ingredients
|20c||Do not apply directly to water within the species habitat (described under the Shading Key).|
Yuma clapper rail [Rallus longirostris yumanensis]
The Yuma clapper rail is one of seven North American subspecies of the clapper rail, a henlike marsh bird. The Yuma subspecies is graybrown with a tawny breast, a white throat and undertail, and bars across its flanks. The Yuma clapper rail is a large bird, measuring 36 to 42 centimeters (14 to 16 in) in length.
Clapper rails feed on crayfish, small fish, clams, isopods, and a variety of insects. The birds remain on their US breeding grounds from mid-April to mid-September, when they migrate south to Mexico for the winter. The Yuma clapper cail is a mysterious creature in its breeding and nesting practices. It is thought that the bird lays about six eggs. They construct their various types of nests on dry hammocks or in small shrubs amid dense cattails, just above water level.
In the United States, the Yuma clapper rail seeks out nesting sites among tall cattails and bulrushes along the margins of shallow, stable ponds of freshwater marshes. Western clapper rails range from northern California to central Mexico. It is possible that the Yuma subspecies did not exist in the US along the lower Colorado River area until larger marshes were formed following dam construction. Today, the estimated 1,700-2,000 birds occur in the freshwater marshes along the lower Gila River, the Salton Sea, and along the Colorado River from Needles, CA southward.
Water control projects on the Colorado River have built dams which altered the nature of this free-flowing body of water. Some backwaters were eliminated, but the dams created much new habitat for the birds by allowing sedimentation, which in turn allowed cattail and bulrush marshes to emerge. However, other suitable rail habitat has been lost through dredging and channelization projects along the Colorado River. In addition, the Salton Sea, while providing a significant amount of habitat, is becoming very salty. Regular outbreaks of botulism there have killed numerous birds, including rails.
Although the rail population appears stable, there is no denial that its fate is directly related to the various water projects along the Colorado River. It is clear that the key to preserving the Yuma clapper rail is the maintenance of early growth stages of cattail marsh by creating shallow water areas. The mats of dead cattails in the shallows will eventually provide nesting cover for the rails.
Matthews, J.R. (ed.). 1990. The Official World Wildlife Fund Guide to Endangered Species, Beacham Publishing Inc, Washington, DC. Vol II, pp. 690-691.