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 15 May and 15 August 2004. Eighty-two transient flycatchers of unknown subspecies were detected during surveys. Transients occurred in a range of habitat types including mixed willow riparian, willow-sycamore dominated riparian, oak-sycamore dominated riparian, riparian scrub, and upland scrub. The distance from transient locations to the nearest surface water averaged 274 ± 374 m (N = 72).

Number of pages: 60

Authors: Kus, Barbara; Kenwood, Kerry E.;

Year: 2004

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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