Restoration Potential: A relatively common species and has apparently increased where favorable habitat has increased, such as early seral stands in northern California forests. Potential for increasing populations is high where it is possible to restore willow (SALIX sp.) and other shrubby riparian habitats.
Preserve Selection and Design Considerations: Much of the habitat in northern and upland forests is found on federal lands (National Forests and National Parks). There is greater concern for conservation of riparian habitats throughout the West that have undergone extensive alteration due to agriculture, water developments, grazing and urban development. Optimum patch sizes and most aspects of landscape relationships are unknown. Patch size would presumably depend on habitat quality given the species' geographic variation in density. Preference for riparian and moist brushy habitats suggest they may use riparian corridors for travel. Although use brushy ecotones, they may respond more to vegetation structure than to edge itself (USDA Forest Service 1994).
Management Requirements: TIMBER HARVEST: Has increased and extended its range in northern California Douglas-fir (PSEUDOTSUGA MENZIESII) forests that have undergone extensive timber harvesting, creating stands of shrubby second-growth (Morrison and Meslow 1983). This pattern likely holds for most northern conifer forests in its range (Pitocchelli 1995). Populations in forested regions will undoubtedly fluctuate and will probably increase in the short- and medium-term with trends in timber harvest practices and the availability of such brushy seral habitats. No information available on effects of timber harvesting in cottonwood (POPULUS sp.) riparian or aspen (POPULUS TREMULOIDES), but practices that reduce shrubs, seedlings, and saplings likely have adverse effects.
GRAZING: Intensive grazing that reduces or eliminates brush and shrubs, particularly in riparian habitats, is undoubtedly detrimental, but the details on response to different grazing regimes or habitat parameters is unknown. Most available studies examined only species presence/absence and lack treatment replicates, either comparing a single grazed plot with a single ungrazed plot, or comparing several plots within a single riparian zone. In cottonwood (POPULUS TRICHOCARPA) and Ponderosa pine (PINUS PONDEROSA) riparian woodland of western Montana, were absent on a heavily-grazed site but bred on a lightly-grazed site; percent ground cover, bush cover, mid-canopy cover, bush volume, canopy volume, and numbers of trees and shrubs differed significantly between the sites (Mosconi and Hutto 1982). Grazing had a negative effect on species presence in aspen communities in California and Nevada (Page et al. 1978 cited in Saab et al. 1995) and aspen (POPULUS TREMULOIDES)/willow (SALIX sp.) communities in Nevada (Medin and Clary 1991).
FIRE: No direct information is available on the effects of wildland or prescribed fire on this species. Burns that result in the regeneration of brush and deciduous saplings in forest stands and riparian habitats should be beneficial.
PESTICIDES: Cholinesterase (ChE) inhibitors (organophosphates and carbamates) used as insecticides can disrupt bird nervous systems, resulting in death. In a Montana and Oregon study, 78 percent of birds sampled (n = 14) showed a 23 percent to 51 percent depression in ChE activity in the brain when exposed to acephate insecticide (Orthene, O-methyl S-methyl N-acetylphosphoramidothioate) sprayed on forests at 1.13 kilograms per hectare. This pesticide caused a marked response in 13 other passerine species as well. No ChE response reported from MacGillivray's in plots sprayed with carbaryl or tricholorfon, though it is unclear from the data whether the species was collected on those plots (Zinkl et al. 1977). Pesticide effects on population, reproduction, development, and survival unknown.
Management Research Needs: Largely unstudied and many contributions could be made to the understanding of its biology. Little is known about courtship, parental care, mate fidelity, philopatry, survivorship, migration routes, extent of wintering range, non-breeding habitat requirements and diet, or non-breeding social structure and behavior. Further information needed on relations to management practices, including logging, grazing, and activities that alter stream vegetation (such as water developments, agriculture, and housing developments). Sensitivity to different grazing regimes in various riparian and shrub habitats grazing deserves further study. Landscape relations (patch size, area sensitivity, use of corridors) unknown. More work needed on vulnerability to predation and parasitism in relation to landscape patterns. Use of stopover habitats, threats on wintering grounds unknown. Sensitivity to most pesticides and herbicides unknown.