YUMA CLAPPER RAIL Rallus longirostris yumanensis (Dickey) 



Order: GRUIFORMES Family: RALLIDAE 



Distinguishing characteristics : In size and appearance similar to a small hen, but has 

 long, slender, slightly decurved bill, longish legs. Very short tail is white beneath. 

 General color tawny and grayish with barred flanks . Paler and smaller than other 

 American clapper rails . Downy young are black . 



Present distribution : Restricted in the breeding season to cattail-tule marshes along 

 lower Colorado River from the Colorado Delta in Mexico north Needles, California, in two 

 small marshes along the lower Gila River, in two small marshes immediately south of 

 Phoenix, Arizona, and at the lower end of the Salton Sea. Concentrated mainly in Havasu 

 Lake , Cibola , and Imperial National Wildlife Refuges . Birds migrate but winter range 

 unknown at this time . 



Former distribution : Marshes of the lower Colorado River from the Parker area south 

 into the delta, in Mexico, and at the southeastern end of Salton Sea. 



Status : Occurs in small numbers and limited breeding habitat due to continuing channeli- 

 zation of the Colorado River with its continued loss of marshes and sloughs through 

 draining and covering with spoil. At Salton Sea, increasing salinity of water and 

 destruction of vegetation in drainage canals has eliminated suitable habitat. 



Estimated numbers : 500 to 1,000 individuals along either side of lower Colorado River 

 in Arizona and California . Survey in May and June 1969 along 240 miles of river recorded 

 142 birds. 



Breeding rate in the wild : Very little data; probably six to ten young . 



Reasons for decline : Not certain that it has declined but adverse factors are drainage of 

 marshes by channelization and filling programs . Increased salinity of Salton Sea and 

 removal of marsh plants by both physical and chemical means . 



Protective measures already taken : Setting aside of Havasu Lake , Imperial , and Cibola 

 National Wildlife Refuges on Colorado River. Study underway by Bureau of Sport Fisheries 

 and Wildlife biologist to determine numbers of birds, their distribution, and habitat 

 requirements . Fully protected under California Fish and Game Code . 



Measures proposed : Marsh management on public lands within the range of this subspecies 

 for specific purpose of providing clapper rail habitat . Continuing surveys to determine 

 location and size of populations . Study of taxonomic relationship of clapper rails of the 

 lower Colorado River Valley and populations of this species along the Gulf of California. 

 Band Yuma clapper rails to determine wintering area. 



References : 



Dickey , D . R . Description of a new clapper rail from the Colorado River Valley . 



Auk 1923:90-94. 

 Phillips, A., J. Marshall, and G . Monson . The birds of Arizona. Univ. of Arizona 



Press, 1964. p. 31. 

 Tomlinson, R. E. Administrative reports. Bureau of Sport Fisheries and Wildlife. 



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