Wildlife Specialist report

and collisions (Gaines et al. 2003). Knight and Cole (1991) indicate that birds may
respond to human activity by altering their behavior, spatial distribution, and habitat use.
Corridors created by roads can fragment songbird habitat, and human activity within
these areas may displace or disrupt breeding activity for songbirds and other avian
species (Hamann et al. 1999). Increased nest parasitism by Brown-headed Cowbirds and
increased access by nest predators is also a major source of disturbance in fragmented
riparian ecosystems. Fragmentation of limited, high value habitats such as riparian
corridors may result in some of the most severe impacts to songbirds (Hamann et al.
1999). Hutto (1995) indicates that many songbird species are largely or exclusively
restricted to riparian habitats. Therefore, it can be inferred that songbirds occupying these
specific habitats will be more affected by riparian corridor fragmentation via roads and
trails, than fragmentation of adjacent forests (Hamann et al. 1999). A recommended
corridor buffer of 100 meters or greater was suggested as the minimum width within
fragmented riparian habitat necessary to minimize effects to songbirds (Vander Hagen
and Degraaf 1996). Other researchers have suggested managers buffer minimum corridor
widths from 75–175 meters to include at least 90 percent of all songbird species that may
be impacted by road fragmentation of habitat. This analysis used a buffer of 100 meters
on each side of the road to analyze the effects of roads to riparian bird species. Road
miles and densities in riparian corridors were the analytical tool by which direct effects to
riparian bird species were measured.
Southwestern Willow Flycatcher [(SWWF) Federally “Endangered” Species with
Designated Critical Habitat, and NM PIF High Priority Species with Known
Territories on the GNF] - The Southwestern Willow Flycatcher (SWWF)/ breeds in
dense riparian habitats in southwestern North America, and winters in southern Mexico,
Central America, and northern South America (USFWS, 2002). The subspecies was
listed as endangered effective March 29, 1995 (USFWS, 2002). The SWFL breeds in
relatively dense riparian tree and shrub communities associated with rivers, swamps, and
other wetlands, including lakes (e.g., reservoirs) (USFWS, 2002). The size of the New
Mexico population in 2007 was estimated at 800-900 birds, based on the documentation
of approximately 514 territories and 403 nests (NMPIF 2010). The total species
population is estimated at 1,200 territories or approximately 2,400 individuals (Durst et
al. 2008). About 32% of the global population is thought to occur in New Mexico
(NMPIF, 2010). On the Gila National Forest we have had two sites that have been
consistently occupied for over 10 years along the Gila River. These two areas are in
locations known as the Gila Bird Management Area (GBMA) and the Fort West ditch
site. In 2008 seven territories were found at the GBMA and four territories at the Forest
West ditch site (Shook 2009). In 2007 a new breeding site was discovered on the Forest
along the San Francisco River (Keller Canyon site). The Keller Canyon site, located on
the reach between Deep Creek and Alma Highway 180, had three flycatcher territories in
2007, 2008, and 2009.
The Ubar Ranch, found in the Cliff/Gila Valley on private land, is located near the two
sites on the Gila River on the Forest, and is one of the largest sites known throughout the
subspecies range. In 2008, 140 territories were detected on the Ubar Ranch (Durst et al
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