Distribution, Abundance, and Breeding Activities of the Southwestern Willow Flycatcher at Marine Corps Base Camp Pendleton, California

Type: report

Article abstract: Surveys for the endangered Southwestern Willow Flycatcher (Empidonax traillii extimus) were conducted at Marine Corps Base Camp Pendleton, California, between 24 June and 12 August 2011. Surveys in 2011 began later than usual (late June vs. 15 May) because of contract delays. Consequently, data collected in 2011 may not be directly comparable to other years and represents a minimum population estimate. Drainages containing riparian habitat suitable for flycatchers were surveyed one to three times. No transient flycatchers of unknown sub-species were observed during Base-wide surveys.

Number of pages: 46

Authors: Howell, Scarlett L.; Kus, Barbara;

Year: 2011

Purpose: The purpose of this study was to document the status of Southwestern Willow Flycatchers at Marine Corps Base Camp Pendleton in San Diego County, California. Specifically, our goals were to (1) determine the size and composition of the Willow Flycatcher population at the Base, (2) document survivorship and movement of resident flycatchers, (3) document nesting activities, and (4) characterize habitat used by flycatchers. These data, when combined with data from other years, will inform natural resource managers about the status of this endangered species at Camp Pendleton, and guide modification of land use and management practices as appropriate to ensure the species’ continued existence.

Prepared for: Assistant Chief of Staff, Environmental Security U.S. Marine Corps Base Camp Pendleton;

Keywords: cowbird parasitism; habitat loss;

Species: Southwestern willow flycatcher

Vegetation communities: riparian forest & scrub

Threats: Parasitism/disease

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