Chapter 3 - Natural Resources - Marine Corps Base Camp Pendleton
Chapter 3 - Natural Resources - Marine Corps Base Camp Pendleton
Chapter 3 - Natural Resources - Marine Corps Base Camp Pendleton
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MCB <strong>Camp</strong> <strong>Pendleton</strong>, California<br />
MCBCP<br />
On <strong>Camp</strong> <strong>Pendleton</strong>, light-footed clapper rails were detected in the Santa Margarita River<br />
mouth (1982-1988 and 2002-2008), Cocklebur Canyon mouth (1982), and San Luis Rey<br />
River Mouth (1992) (Zembal et al. 2008). Total sightings on <strong>Base</strong> have not been greater<br />
than three pairs for a single survey season since 1982, and never greater than two pairs<br />
from 1983 to 2008 (Zembel et al. 2008 & Kershner pers. comm. 2009). From 1980 to 1989<br />
seven estuaries/marshes were surveyed on <strong>Base</strong>: San Mateo Creek Mouth, Las Pulgas<br />
Canyon Mouth, Las Flores Marsh, French Canyon Mouth, Cocklebur Canyon Mouth,<br />
Santa Margarita Lagoon, and San Luis Rey River Mouth (Zembel et al. 2008). From 1990<br />
to 2007 five estuaries/marshes were surveyed on <strong>Base</strong>: San Mateo Creek Mouth, Las Flores<br />
Marsh, Cocklebur Canyon Mouth, Santa Margarita Lagoon, and San Luis Rey River Mouth<br />
(Zembel et al. 2008). For detailed information on the light-footed clapper rail and its<br />
management on <strong>Base</strong>, see Appendix F, Section F.10.<br />
3.2.4.7. Southwestern Willow Flycatcher (Empidonax traillii extimus)<br />
FIGURE 3-17.<br />
The southwestern willow flycatcher<br />
(Empidonax traillii extimus) measures<br />
about 5.75 inches in length and weighs<br />
only about 0.4 ounces. Overall, it is<br />
roughly the size of a small sparrow. Both<br />
sexes look alike. The flycatcher’s<br />
appearance is overall greenish or<br />
brownish gray above, with a white throat<br />
that contrasts with a pale olive breast.<br />
The belly is pale yellow. Two white wing<br />
bars are visible, but the eye ring is faint<br />
or absent. The upper mandible is dark and<br />
the lower mandible light. The<br />
southwestern willow flycatcher inhabits<br />
riparian areas along rivers, streams, and<br />
other wetlands. It nests in typically evenaged,<br />
structurally homogeneous, dense<br />
stands of trees and shrubs approximately 13-23 feet tall with a high percentage of canopy<br />
cover and dense foliage from 0-13 feet above the ground (Brown 1988; Sedgewick &<br />
Knopf 1992). The southwestern willow flycatcher is a neotropical migrant. The Special<br />
Management Season of the southwestern willow flycatcher extends from 15 March through<br />
31 August. Factors contributing to the decline of the southwestern willow flycatcher are<br />
attributed to loss and degradation of nesting habitat, nest parasitism by cowbirds and<br />
human disturbance.<br />
Management Status<br />
SOUTHWESTERN WILLOW<br />
FLYCATCHER<br />
(PHOTO SOURCE: USGS)<br />
Federal Status<br />
The southwestern willow flycatcher (Empidonax traillii extimus) was federally listed as an<br />
endangered species by the USFWS on 27 February 1995 (USFWS 1995c). On 22 July<br />
1997, the USFWS designated critical habitat for this species (USFWS 1997a), but was later<br />
remanded and vacated. A second proposal for the designation of critical habitat has been<br />
3-48 <strong>Chapter</strong> 3 – <strong>Natural</strong> <strong>Resources</strong>