2007 Survey for Yuma Clapper Rails and Southwestern Willow Flycatchers Along Las Vegas Wash, Clark County, Nevada
SWCA Environmental Consultants. 2008. 2007 Survey for Yuma Clapper Rails and Southwestern Willow Flycatchers Along Las Vegas Wash, Clark County, Nevada. Southern Nevada Water Authority. Salt Lake City, UT
Systematic surveys for Yuma clapper rails (Rallus longirostris yumanensis) were conducted within potentially suitable habitat along the Las Vegas Wash (Wash) in Clark County, Nevada, from April through May 2007. The survey techniques included playback recordings of the Yuma clapper rail in accordance with standardized survey protocol (McKinstry 1995). No clapper rails were detected. Systematic surveys for southwestern willow flycatchers (Empidonax traillii extimus) were conducted along the Wash from May through July 2007. The survey techniques included playback recordings of the southwestern willow flycatcher in accordance with standardized survey protocol (Sogge et al. 1997). One willow flycatcher was detected during the third survey period, which is the latest a willow flycatcher has been detected in the Clark County Wetlands Park (Park) in systematic surveys dating back to 1998. Although detected only once, it was determined to be a resident southwestern willow flycatcher per the protocol (Sogge et al. 1997), and is the first confirmed detection of the federally endangered subspecies along the Wash. While no official surveys were conducted for the western yellow-billed cuckoo (Coccyzus americanus occidentalis), special care was taken to listen for the species and evaluate potentially suitable habitat while conducting southwestern willow flycatcher surveys. No individuals were detected. Previous survey reports (SWCA 2002, 2003, 2004, 2007) have identified both increases and losses of potential Yuma clapper rail habitat. Generally, construction of erosion control structures has continued to increase the quantity of emergent wetland habitat within the boundaries of the Park. However, some marsh areas have become increasingly channelized, reducing the habitat quality within these areas. Additionally, emergent marsh habitat along the lower C-1 Channel in which a Yuma clapper rail was detected in 2006 was destroyed by construction of a concrete- and riprap-lined flood control channel prior to the 2007 breeding season. Presently, the Wash still provides only marginal habitat for nesting Yuma clapper rails. Previous survey reports (SWCA 1999–2007) have identified losses of potentially suitable southwestern willow flycatcher habitat. Habitat losses continued into 2007 and were primarily associated with wildfire, ongoing construction of erosion control and bank stabilization structures, and large-scale revegetation efforts in the survey area. Such events, while the cause of additional tamarisk losses, will likely lead to long-term improvements in potentially suitable southwestern willow flycatcher habitat, as well as potentially suitable clapper rail and western yellow-billed cuckoo habitats. Cottonwood and willow plantings continue to mature, thus improving riparian habitat structure and suitability for cuckoos and flycatchers.
- Type
- Unpublished Report
- Authors
- SWCA Environmental Consultants
- Date of Issue
- 2008-12-31
- Publisher
- Southern Nevada Water Authority
- Units
- LAKE
- Keywords
- Absence (Biodiversity), Abundance (Biodiversity), Animal Studies, Aves (Birds), Coccyzidae (Spotted-tailed Cuckoos Lizard-cuckoos), Coccyzus americanus (Yellow-billed Cuckoo), Cuculiformes, Distribution (Biodiversity), Empidonax Traillii (Willow flycatcher), Endangered Species, Gruiformes, Management, Passeriformes (Perching Birds), Presence (Biodiversity), Rallidae (Coots Rails), Rallus longirostris (Clapper Rail), Taxa Links To References, Tyrannidae (Tyrant Flycatchers), Wildlife