West Mojave Plan FEIR/S - Desert Managers Group

Regulatory Status: Federal Endangered, California Endangered.Threats Affecting the Southwestern Willow Flycatcher: Habitat loss and degradationand brood-parasitism by the brown-headed cowbird are the biggest threats.3.3.6.12 Summer TanagerLife History: Western populations of the summer tanager require riparian woodland orforest dominated by cottonwoods and willows, usually in a climax stage. Little quantitative dataexist regarding the composition of summer tanager habitat in the California deserts. Fivevegetation plots conducted within tanager territories at Mojave Narrows Regional Park in 1991revealed a canopy cover of 60-85%. The same plots had shrub cover from 1-23%, andherbaceous cover from 25-90%.Population Status in the Planning Area: Summer tanagers have nested at thefollowing localities within the western Mojave: Big Rock Creek near Valyermo (1-2 pairsannually, Little Rock Creek (1-2 pairs in the West Mojave, and 1-2 pairs on the adjacent AngelesNational Forest), Mojave River at Victorville (10-15 pairs annually), Cushenbury Springs (1pair, at least sporadically), Morongo Valley (2-4 pairs annually), and Yucca Valley (1 pairannually). A female or immature was observed at Camp Cady in August 1997, suggestingpotential breeding.Numbers along the Mojave River at Victorville have increased notably over the past 11years: from 3 or 4 pairs in 1987 to 12-15 pairs in 1996, and at least 12 pairs in 1997. In 2000, 15birds were counted in the Mojave River between Victorville and Helendale in an area notpreviously surveyed. The population at Big Rock Creek has remained stable since the early1980s at 1-2 pairs annually. Breeding at the golf course at Yucca Valley has been sporadic.Regular fieldwork has not been conducted at Cushenbury Springs, so the summer tanager'scontinuity there is not known.Regulatory Status: California Species of Special Concern.Threats Affecting the Summer Tanager: Habitat destruction is the primary threat tosummer tanagers in California. Habitat destruction can occur in several ways, with the mostcatastrophic losses resulting from clearing of large tracts of forest or woodland for agriculture,development, or flood control. On a smaller scale, activities such as woodcutting can degrade ordestroy suitable breeding habitat for this species. Groundwater pumping can gradually make theriparian habitats unsuitable.3.3.6.13 Vermilion FlycatcherLife History: This species occupies habitat with open riparian areas with accessiblewater and dominated by mesquite with willow and Fremont cottonwood. It uses parkland or golfcourse settings that support either native or non-native trees, and may or may not have accessiblewater. In native habitats, trees used for nesting range from massive cottonwoods, sycamores,and even oaks to smaller trees such as willow and mesquite.Chapter 3 3-179