Setophaga nigrescens

BREEDING: Breeds in a variety of semi-arid woodlands; dry, open forests; mixed, moist forests; brushlands; chaparral. Especially uses conifers, live oaks, and mixed pinyon-juniper woodlands (Dunn and Garrett 1997). Inhabits juniper-pinyon-oak scrub on slopes, foothills, and canyons, where (in Wyoming) it is strongly associated with the presence of pinyon pine and high seedling/sapling density and understory height (Pavlacky and Anderson 2001). Also inhabits fir forests and edges of clearings. Nests in trees or shrubs 1-10 meters above ground, sometimes up to 15 meters (Harrison 1978; M. Guzy, pers. comm.). An early observer noted that the species likes well-scattered conifers; prefers high and dry places; and does not mind marsh or river nearby if ground beneath the nest is dry (Bowles 1902).

Generally uses younger age classes in northwest forests. In Douglas-fir forests in western Washington and Oregon, Meslow and Wright (1975) found the species nesting in shrub-sapling (7-15 years old), older second growth (41-120 years) and mature (> 120 years) successional communities, and using but not nesting in 16-40 year-old second growth. In Oregon Coast Range Douglas-fir forests, Carey et al. (1991) found highest densities in young stands (40-72 years; 9.06 birds per 40 hectares two-year average) in contrast to mature (80-120 years; 2.37 birds per 40 hectares two-year average) and old-growth stands (200-250 years; 3.04 birds per 40 hectares two-year average). Young stands typically had high densities of small-diameter trees (mean 269.7 stems per hectare of trees 10-19 centimeter dbh) and low densities of large trees over 50 centimeter dbh; also few large snags and low vertical foliage density. Similarly, in Douglas-fir forests of the Washington Cascades, were detected more frequently in young stands (55-80 years; mean 0.19 birds per visit) than in mature (95-190 years; 0.02 birds per visit) or old-growth stands (300-730 years; 0.06 birds per visit; Manuwal 1991). Young stands contained the highest mean densities (70 trees per hectares) of live trees less than 50 centimeter dbh and high densities (70 per hectare) of small snags less than 19 centimeter dbh. Huff and Raley (1991) also detected birds more often in young stands than in mature and old-growth stands in the Oregon Coast Ranges and Southern Washington Cascades, but in the Oregon Cascades they found little difference between stand age classes although the species was detected on a slightly greater percentage of old-growth stands.

On Vancouver Island, British Columbia, most often found in 50- to 60-year-old stands of mixed forests; an important elementis relatively open but brushy undergrowth (Campbell et al. 2001).

In southern Idaho, uses low ridges covered with open junipers (Burleigh 1972). In California, inhabits dry, open woodlands and brushy understories of foothills and mountains; breeds in ponderosa pine (PINUS PONDEROSA), valley-foothill hardwood-conifer, montane hardwood and pinyon-juniper habitats, and prefers oak woodland or pinyon-juniper mixed with chaparral or brushy understories (USDA Forest Service 1994). In northwestern Colorado pinyon-juniper habitat, prefers late-successional woodlands and occurs in similar woodland habitat to Plumbeous Vireo (VIREO PLUMBEOUS) and Dusky Flycatcher (EMPIDONAX OBERHOLSERI; Sedgwick 1987). In the Northwest, will use stands of regenerating deciduous trees and conifers in old clearcuts and burns (Dunn and Garrett 1997). In northern Arizona pinyon-juniper, observed to use and nest in juniper slightly more than other bird species (Balda 1969). In Mexico and northern Central America, breeds in semi-arid pine-oak and juniper woodland (Howell and Webb 1995). Breeds from 3,000 to 7,000 feet in the Sierra, up to 9,500 feet in White Mountains, California, but much lower in the Northwest (Dunn and Garrett 1997).

NON-BREEDING: In winter, uses arid mountain woodlands, including pine-oak. May use riparian habitats as travel corridors (USDA Forest Service 1994). In California, uses oaks and riparian willows and cottonwoods; in southwestern U.S., bottomland cottonwoods, willows, mesquite, and sycamores (Dunn and Garrett 1997). In Mexico and northern Central America, winters in arid to semi-humid oak and pine-oak forest and scrub (Howell and Webb 1995). In western Mexico, Hutto (1992) classified this species as a two-zone generalist that primarily uses tropical deciduous forest and thorn forest, and only 5 percent of observations were in pine-oak forest.

Seen singly or in pairs; may be seen in small groups while migrating.

Clutch size is three to five (usually four). Incubation is done by female. Young are tended by both parents (Harrison 1978).