WSP03308 - Laserfiche WebLink

Home Browse Search

.' . . Area Manager DRAFT 34 Taos, on both the mainstem Rio Grande and on the Rio Grande de Rancho, a tributary to the upper Rio Grande. In recent years, breeding pairs have also been found on the Chama River up to L'1e vicinity of Los Ojos. uiah Distribution and Abundance. Specimen data reveal that the flycatcher historically occurred in southern Utah along the Colorado River, San Juan River, Kanab Creek, Virgin River, and Santa Clara River (Unitt 1987). The flycatcher no longer occurs along the Colorado River in Glen Canyon, where Lake Powell inundated historically occupied habitat, nor in unflooded portions of Glen Canyon near Lee's Ferry where flycatchers were documented nesting in 1938. Similarly, recent surveys on the Virgin River and tributaries and Kanab Creek have failed to document their presence (McDonald et ai, 1995). Colorado Distribution and Abundance. The taxonomic status and the historic distribution and abundance of flycatchers in southwestern Colorado remain unclear due to a lack of specimen data and breeding records. Preliminary data on song dialects suggest that the few birds recently documented in southwestern Colorado may be E. t. extimus. These sightings have prompted State and Federal agencies to delineate provisional boundaries for flycatchers and sponsor Statewide surveys. Surveys since 1993 have documented flycatchers at six locations in Delta, Mesa, and San Miguel Counties. Arizona Distribution and Abundance. As reported by Paradzick et al. (2000), the greatest concentrations of flycatchers in Arizona in 1999 were near the confluence of the Gila and San Pedro rivers (236 flycatchers, 134 territories); at the inflows of Roosevelt Lake (140 flycatchers, 76 territories); between Fort Thomas and Solomon on the middle Gila River (9 flycatchers, 6 territories); Topock Marsh on the Lower Colorado River (30 flycatchers, 16 territories); Verde River at Camp Verde (7 flycatchers,S territories); Alpine/Greer on the San Francisco River/Little Colorado River (I I flycatchers, 8 territories); Alamo Lake on the Bill Williams River (includes Santa Maria and Big Sandy river sites) (43 flycatchers, 23 territories); and Lower Grand Canyon on the Colorado River (21 flycatchers, II territories). Unitt (1987) concluded that "probably the steepest decline in the population level of E. t. extimus has occurred in Arizona..." Historic records for Arizona indicate the former range of the flycatcher included portions of all major river systems (Colorado, Salt, Verde, Gila, Santa Cruz, and San Pedro) and major tributaries, such as the Little Colorado River and headwaters, and White River. As of 1999,289 territories were known from 47 sites along 12 drainages Statewide. The lowest elevation where territorial pairs were detected was 197 feet at Adobe Lake on the Lower Colorado River; the highest elevation was at the Greer town site (8,300 ft). The majority of breeding groups in Arizona are extremely small. Of the 47 sites where flycatchers have been documented, 70 percent (n = 33) contain five or fewer territorial flycatchers. California Distribution and Abundance. The historic range of E. t. extimus in California apparently included all lowland riparian areas in the southern third of the State. It was considered a common breeder where suitable habitat existed (Wheelock 1912, Grinnell and Miller 1944). Unitt (I984, 1987) concluded that it was once common in the Los Angeles basin, the San BernardinolRiverside area, and San Diego County. Specimen and egg/nest collections confirm its former distribution in all coastal counties from San Diego County north to San Luis OOH3~