Chapter 3 - Natural Resources - Marine Corps Base Camp Pendleton

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