California Black Rail
(Laterallus jamaicensis coturniculus)
- DESCRIPTION
- DISTRIBUTION
- HABITAT
- CONSERVATION
- MULTIMEDIA
General Description
The black rail is the smallest rail in North America. The California black rail subspecies (Laterallus jamaicensis coturniculus) is smaller and brighter colored than the eastern subspecies. The black rail is very secretive and seldom seen; it runs swiftly and quickly on the ground, is generally reluctant to fly, and its short flight is typical of rails. Its flight can be fast and strong over long distances. It can also swim for short distances. The adult coloration is generally shades of pale to blackish gray, and the top of the head is darker than the surrounding plumage. The underparts are uniformly colored but lighter on the chin and throat. Its flanks and area under the tail are streaked with white and dark gray and washed with chestnut. The base of the neck and upper back are also chestnut. The rest of the back, the top of its tail, and wing are shades of dark gray, sometimes with a chestnut or brown wash, and scattered with white spots. The amount of spotting varies between individuals. The tail feathers are brownish gray. The juvenile plumage is similar to the adult but duller, the white spots fewer and smaller, and the streaking on the flanks thinner and less distinct. The eyes of the adult are shades of bright red, while juveniles’ eye color can range from olive to dull orange. The plumage of the California black rail is sexually dimorphic (males and females have different colorations); the throat of the female is pale gray to white and the belly is medium to pale gray, whereas the male is darker with a pale to medium gray throat. The sexes are similar in size. The bill of the black rail is short and black. The foot and toes are a grayish brown color. The downy young are covered with black down and only distinguishable from other rails by their smaller size.
Legal Status
The U.S. Fish & Wildlife Service lists the California black rail as a migratory nongame bird of special concern. In Arizona, it is listed as a wildlife species of special concern. In California, this subspecies is listed as threatened. It is not listed in Nevada. The California black rail is listed as endangered in Mexico.
Taxonomy
The California black rail (Laterallus jamaicensis coturniculus) is one of five subspecies of the black rail that are found in North, Central, and South America. The California black rail was formerly known as the Farallon rail (Creciscus coturniculus), from a type specimen collected on the Farallon Islands of northern California in 1859.
Reproduction
The California black rail form pairs as early as late February. The nest is a well-defined bowl, with a canopy of dead or living vegetation woven over the top and a ramp of dead vegetation leading to an entrance on the side of the nest. Nests are primarily made of southern cattail or spikerush, and are elevated above the mud substrate in clumps of vegetation, which may include: California or giant bulrush, southern cattail, and three-square bulrush. Nest traits are similar to those for eastern black rails. Black rails have also been known to nest on top of a mat of dead vegetation from the previous years’ growth. California black rail lays eggs between early March and early July. Average clutch size ranges from 3 to 8 eggs. Both sexes incubate the eggs and the incubation period for nests range from 17 to 20 days. Chicks hatch one at a time and are born semiprecocial; they require brooding by one parent for the first few days after hatching. Juvenile birds disperse widely from the breeding areas and may appear in untypical habitat.
Diet
Small aquatic and terrestrial invertebrates and seeds are main food items for the black rail. Black rails in Arizona were found to consume diving beetles, ground beetles, other beetles, earwigs, and the seeds of Olney bulrush, California bulrush, and southern cattail during the breeding season. In late summer and autumn, their diet included grasshoppers, beetles, ants, earwigs, spiders, snails, bulrush seeds, and insects. During winter, they ate mostly bulrush seeds but also earwigs, beetles, ants, and cattail seeds. The bill shape of the black rail suggests that it feeds by gleaning and pecking at individual items and relying on sight for finding food. The black rail is probably a daytime feeder and is active throughout the day.
Threats
Documented bird predators of the California black rail include great egret, great blue heron, ring-billed gull, northern harrier, short-eared owl, and possibly loggerhead shrike. Rails forced from habitat by high tides are vulnerable to predation if they are unable to secure upland cover. Rails have been collected after collisions with radio towers and buildings, as well as after encounters with automobiles. California black rails prefer marsh habitat with very shallow water levels of less than 1.2 in (3 cm), and management actions that cause significant or long-term fluctuations of water level are a threat.
Selenium may be a threat to the California black rail along the lower Colorado River. Adult black rails lose their flight and tail feathers during their molt between July 1 and August 31 and remain flightless for up to 3 weeks, making them more vulnerable to predators, as well as wildfires or controlled fires.
More Information
Additional information on this species, as well as source documentation, can be found in the species accounts located at this link (PDF). The Conceptual Ecological Model (CEM) can be found here (PDF). Technical Reports on this species can be found here.
Updated December 30, 2016
The California black rail range is the Pacific coast of California, along the lower Colorado River, and portions of the Bill Williams River. During the breeding season, the California black rail is found north of San Francisco at Bodega Bay, Tomales Bay, and Bolinas Lagoon, the northern reaches of the San Francisco Bay estuary, and Morro Bay. Further to the south, the rail is presently found at seep marshes and springs along the Coachella and All American canals, at one location on the New River south of the Salton Sea, and at Big Morongo Canyon in San Bernardino County. Along the lower Colorado River, the California black rail is found at the Cienega de Santa Clara and several other sites in the Colorado River Delta in Mexico. It is found from Laguna Dam north to Imperial Reservoir, portions of the Imperial NWR, on Colorado River Indian Tribe lands, at the Bill Williams River National Wildlife Refuge, and the Havasu National Wildlife Refuge. Adult populations appear to be sedentary, but juveniles may disperse erratically and colonize new areas.
The image below shows the distribution range of the California black rail.
The California black rail inhabits tidal marshes and freshwater marshes in the western United States and Mexico. It uses sites with shallower water than other North American rails. California black rails inhabit the drier portions of wetlands. Inland sites, such as those along the lower Colorado River are characterized by shallow, stable water level, gently sloping shorelines, and vegetation dominated by fine-stemmed bulrush or grasses. Black rails use dense stands of three-square bulrush along the lower Colorado River, and three-square bulrush restricted to shallow water or moist soil. Sites used by California black rails are based more on habitat structure than plant composition. The rails select areas with high stem densities and canopy coverage in shallow water; close to upland vegetation California black rails are also associated with plants of the upland/wetland interface, such as seep willow, arrowweed, saltgrass, and cottonwood. There are few changes in seasonal use of vegetation types of California black rails, although they use shrubs and three-square bulrush more during the post-breeding season than at other times, and juvenile rails select inland saltgrass during the post-breeding season.
LCR MSCP Conservation Measures
The Habitat Conservation Plan provides conservation measures specific to each species. Listed below are the species specific conservation measures for the California black rail. Click on the arrows to expand the table.
| BLRA1—Create 130 acres of California black rail habitat (Minor Modification) |
Steering Committee Motion 11-004 10-27-10 Of the 512 acres of LCR MSCP–created marsh, 130 acres will be created and managed to provide California black rail habitat near occupied habitat in Reaches 3, 4, 5, 6, and 7. This habitat will be provided by designing and managing at least 130 acres of the 512 acres of created Yuma clapper rail habitat to provide habitat for both species. Habitat will be created in patches as large as possible but will not be created in patches smaller than 5 acres. Additional California black rail habitat may be provided by marsh vegetation that becomes established along margins of the 360 acres of backwaters that will be created in Reaches 3, 4, 5, 6, and 7. These small patches of habitat provide cover for dispersing rails, thereby facilitating linkages between existing breeding populations and the colonization of created habitats. Design of created habitat will be directed toward establishing moist-soil marshes that support a predominance of three-square bulrush with suitable water depths to replicate conditions present at Mittry Lake and Bill Williams Delta that support the species. Habitat will be designed and managed to provide an integrated mosaic of patches of cattail, bulrush, and mudflat, interspersed with small patches of open water with varying water depths. |
| BLRA2—Maintain existing important California black rail habitat Areas |
The applicants, under agreements with cooperating land management agencies, will provide funding to those agencies to maintain a portion of existing California black rail habitat in the LCR MSCP planning area (Section 5.4.2 in the HCP). Maintaining important existing habitat areas is necessary to ensure the continued existence of California black rails in the LCR MSCP planning area, provide for the production of individuals that could disperse to and nest in LCR MSCP–created habitats, and support future recovery of the species. Habitat maintenance would likely be undertaken in conjunction with the maintenance of existing Yuma clapper rail habitat. |
| MRM1—Conduct surveys and research to better identify covered and evaluation species habitat requirements |
Conduct surveys and research to better identify covered and evaluation species habitat requirements. Conduct surveys and research, as appropriate, to collect information necessary to better define the species habitat requirements and to design and manage fully functioning created covered and evaluation species habitats. This conservation measure applies to those species for which comparable measures are not subsumed under species-specific conservation measures (Section 5.7 in the HCP). They are not applicable to species for which habitat would not be created under the LCR MSCP Conservation Plan, such as the desert tortoise, relict leopard frog, humpback chub, and threecorner milkvetch. |
| MRM2—Monitor and adaptively manage created covered and evaluation species habitats |
Created species habitats will be managed to maintain their functions as species habitat over the term of the LCR MSCP. Created habitat will be monitored and adaptively managed over time to determine the types and frequency of management activities that may be required to maintain created cottonwood-willow, honey mesquite, marsh, and backwater land cover as habitat for covered species. This conservation measure applies to those species for which comparable measures are not subsumed under species-specific conservation measures (Section 5.7 in the HCP). They are not applicable to species for which habitat would not be created under the LCR MSCP Conservation Plan, such as the desert tortoise, relict leopard frog, humpback chub, and threecorner milkvetch. |
| MRM5—Monitor selenium levels in created backwater and marsh land cover types, and study the effect of selenium released as a result of dredging activities |
Conduct monitoring of selenium levels in sediment, water, and/or biota present in LCR MSCP created backwater and marsh land cover types. If monitoring results indicate that management of the LCR MSCP conservation areas increases levels of selenium in created backwaters and marshes or in covered species that use them, the LCR MSCP will undertake research to develop feasible methods to manage the conservation areas in a manner that will eliminate or compensate for the effects of increased selenium levels. If feasible management methods are identified, they will be implemented. This conservation measure will include monitoring the effects of dredging and dredge spoil disposal associated with creating and maintaining backwaters and marshes. If monitoring results indicate that current or future dredging and dredge spoil disposal methods increase selenium levels, the LCR MSCP will only implement methods that will have the least effect on selenium levels. A study will also be conducted to look at the effects of potential releases of selenium from dredging in general. |
| CMM1—Reduce risk of loss of created habitat to wildfire |
Management of LCR MSCP conservation areas will include contributing to and integrating with local, state, and Federal agency fire management plans. Conservation areas will be designed to contain wildfire and facilitate rapid response to suppress fires (e.g., fire management plans will be an element of each conservation area management plan). |
| CMM2—Replace created habitat affected by wildfire |
In the event of created-habitat degradation or loss as a result of wildfire, land management and habitat creation measures to support the reestablishment of native vegetation will be identified and implemented. |
| AMM1—To the extent practicable, avoid and minimize impacts of implementing the LCR MSCP on existing covered species habitats |
To the extent practicable, establishment and management of LCR MSCP–created habitats will avoid removal of existing cottonwood-willow stands, honey mesquite bosques, marsh, and backwaters to avoid and minimize impacts on habitat they provide for covered species. Temporary disturbance of covered species habitats, however, may be associated with habitat creation and subsequent maintenance activities (e.g., controlled burning in marshes and removal of trees to maintain succession objectives). LCR MSCP conservation measures that could result in such temporary disturbances will, to the extent practicable, be designed and implemented to avoid or minimize the potential for disturbance. In addition to implementing AMM3 and AMM4 below, these measures could include conducting preconstruction surveys to determine if covered species are present and, if present, implementing habitat establishment and management activities during periods when the species would be least sensitive to those activities; or redesigning the activities to avoid the need to disturb sensitive habitat use areas; staging construction activities away from sensitive habitat use areas; and implementing BMPs to control erosion when implementing ground disturbing activities. |
| AMM2—Avoid impacts of flow-related covered activities on covered species habitats at Topock Marsh |
Impacts on groundwater levels that support covered species habitat at Topock Marsh will be avoided by maintaining water deliveries for maintenance of water levels and existing conditions. At times, flow-related activities could lower river elevations to levels that could disrupt diversion of water from the river to the marsh. Improvements to intake structures that allow water to continue to be diverted or other measures to maintain the water surface elevation will avoid effects on groundwater elevation. Avoidance of effects could be accomplished with the purchase, installation, and operation of two electric pumps sized to the current inflow at the Topock Marsh diversion inlet. The pumps would most likely need to be operated during summer to make up for the lower flow periods. Implementation of this conservation measure would maintain existing habitat at Topock Marsh for the Yuma clapper rail, southwestern willow flycatcher, Colorado River cotton rat, western least bittern, California black rail, yellow-billed cuckoo, gilded flicker, vermilion flycatcher, Arizona Bell's vireo, and Sonoran yellow warbler. The extent of covered species habitat impacts that will be avoided by maintaining water deliveries to Topock Marsh are presented in Table 4-2 in the HCP. Maintaining water deliveries to Topock Marsh will also maintain razorback sucker and bonytail habitat associated with disconnected backwaters managed for these species. |
| AMM3—To the extent practicable, avoid and minimize disturbance of covered bird species during the breeding season |
To the extent practicable, to avoid and minimize potential impacts on covered bird species, vegetation management activities (e.g., periodic removal of emergent vegetation to maintain canals and drains) associated with implementation of covered activities and the LCR MSCP that could result in disturbance to covered bird species will not be implemented during the breeding season to prevent injury or mortality of eggs and young birds unable to avoid these activities. Table 5-9 in the HCP describes the breeding period for each of the covered species during which, to the extent practicable, vegetation management activities in each species' habitat will be avoided. |
| AMM5—Avoid impacts of operation, maintenance, and replacement of hydroelectric generation and transmission facilities on covered species in the LCR MSCP planning area |
To the extent practicable, before implementing activities associated with OM&R of hydroelectric generation and transmission facilities, measures will be identified and implemented that are necessary to avoid take of covered species where such activities could otherwise result in take. These measures could include conducting surveys to determine if covered species are present and, if so, deferring the implementation of activities to avoid disturbance during the breeding season; redesigning the activities to avoid the need to disturb covered species habitat use areas; staging of equipment outside of covered species habitats; delineating the limits of vegetation control activities to ensure that only the vegetation that needs to be removed to maintain infrastructure is removed; stockpiling and disposing of removed vegetation in a manner that minimizes the risk of fire; and implementing BMPs to control erosion when implementing ground disturbing activities. |
| AMM6—Avoid or minimize impacts on covered species habitats during dredging, bank stabilization activities and other river management activities |
To the extent practicable, before initiating activities involved with river maintenance projects, measures will be identified and implemented that avoid or minimize take of covered species where such activities could otherwise result in take. Such measures could include alternative methods to achieve project goals, timing of activities, pre-activity surveys, and minimizing the area of effect, including offsite direct and indirect effects (e.g., avoiding or minimizing the need to place dredge spoil and discharge lines in covered species habitats; placing dredge spoils in a manner that will not affect covered species habitats). |
Research and Monitoring Activities
LCR MSCP conduct a variety of research and monitoring activities along the LCR encompassing both MSCP and non-MSCP species. For a complete list of all activities, please see the Research and Monitoring Activities web page.
This gallery includes photos of this species. If you require larger photos, please contact our webmaster Michelle Reilly at mreilly@usbr.gov.
