Rallus obsoletus (incorporating
levipes,
yumanensis and
beldingi) is found along the western coasts of the
USA and
Mexico, disjunctly from San Francisco and San Pablo bays, California, south to Baja California Sur and southern Nayarit, Mexico.
The nominate form is confined to central California, mainly in San Francisco Bay and San Pablo Bay (and Suisun Bay; Overton 2007). Formerly, it also occurred in Morro, Tomales, Humboldt and Monterey Bays (Eddleman and Conway 1998). The population of this form was estimated at 1,167 individuals (range 954-1,426)
in 2009-2011 (Liu
et al. 2012a,b).
Form
levipes is found from coastal central California to northern Baja California and has been estimated to number 190 pairs in the USA and c.240 pairs in Mexico (Eddleman et al. 1988, Ehrlich et al. 1992) and has lost huge areas of habitat, while form yumanensis of southeast California, southern Arizona and northwest Mexico has been estimated to number 1,700-2,000 individuals (Ehrlich et al. 1992) and has experienced increases and decreases in habitat availability, with habitat threatened overall with conversion and high water flows. A more recent population estimate, however, put the population at 6,629 individuals (95% CI: 4,859-8,399) in the Colorado River delta region of Mexico (Hinojosa-Herta et al. 2001). There are apparently no published population estimates for beldingi, which is confined to southern Baja California.Rights Holder: International Union for Conservation of Nature and Natural Resources
Bibliographic Citation: BirdLife International 2014.
Rallus obsoletus. In: IUCN 2014 . IUCN Red List of Threatened Species. Version 2014.1 . <
www.iucnredlist.org>
