Species: Oporornis tolmiei

Densities vary with habitat quality, elevation, season, and location (Pitocchelli 1995). Breeding densities recorded in western Oregon ranged from 0.56 birds per hectare (Morrison and Meslow 1983) to 0.73 males per hectare (Morrison 1981); in Utah, from 0.83 to 1.21 males per hectare, increasing with vegetation cover (Blakesley and Reese 1988); in Washington 0.26 birds per hectare (Miller et al. 1972, cited in Pitocchelli 1995); in Wyoming 0.16 to 0.33 territorial pairs per hectare (Finch 1989a). On wintering grounds in western Mexico, Hutto (1981) recorded 8.5 birds per hectare in evergreen forest edge, 5.6 birds per hectare in thornscrub, 5.0 birds per hectare in plantation, 2.8 birds per hectare in second growth, and 1 bird per hectare in mangrove. Territory size not reported. Site fidelity observed on breeding site in Oregon (Klimkiewicz and Futcher 1989, cited in Pitocchelli 1995) and on wintering sites in El Salvador (n = 4) and Mexico (n = 1; Loftin 1977).<br><br>This warbler is preyed on by accipiters, small mammals and snakes (Zeiner et al. 1990, cited in USDA Forest Service 1994). Females respond to intruders with distraction displays and feigning injury when near nest or fledglings (Jewett et al. 1953, cited in Pitocchelli 1995). On the Mogollon Rim, Arizona, a nest predation rate of 49 percent reported in snowmelt drainages of mixed pine-oak woodland (Martin 1993).