Though this indicates a critically small population, the demographics of the flycatcher paint a worse picture. Flycatcher populations are severely limited by lack of breeding and poor reproductive success. Flycatcher sites are widely scattered and geographically isolated. Destruction of habitat is the primary cause of the flycatcher's perilous status. Cottonwood-willow riparian forests, at one time, formed a nearly continuous network on all major and minor river valleys throughout the Southwest.
Grazing occurs at nearly half of all sites and is limiting habitat recovery rangewide.
Rising reservoir levels behind three dams are threatening four of the largest remaining breeding populations, resulting in authorized take of 80-90 territories. Groundwater pumping throughout the San Pedro watershed is threatening existing populations and an important recovery area. Lack of flooding is a universal problem because of dams and other river management activities, threatening the long-term maintenance of existing habitat and limiting recovery. Though used by flycatchers, tamarisk has invaded a large proportion of river floodplains in the Southwest with an unknown effect on flycatcher habitat use, productivity and survival. Tamarisk may be a population trap for the flycatcher because of its propensity to carry fire.