Associated Species in Sonoran Desert: Other species that may use similar habitat components or respond positively to management for the Cactus Ferruginous Pygmy-owl are: Harris’s Hawk, Gila Woodpecker, Gilded Flicker, Gambel’s Quail, Curve-billed Thrasher, Black-tailed Gnatcatcher, Phainopepla, Cactus Wren, Verdin, Elf Owl, Pyrrhuloxia, Ash-throated Flycatcher, Abert’s Towhee, Hooded Oriole, and Scott’s Oriole.

Associated Species in Lowland Riparian: Other species that may use similar habitat components or respond positively to management for the Cactus Ferruginous Pygmy-owl are: Lucy’s Warbler, Bell’s Vireo, Brown-crested Flycatcher, Bewick’s Wren, Hooded Oriole, Gila Woodpecker, Yellow Warbler, Yellow-breasted Chat, Yellow-billed Cuckoo, Ladder-backed Woodpecker.

Distribution: The Cactus Ferruginous Pygmy-Owl occurs from lowland central Arizona south through western Mexico to the States of Colima and Michoacan, and from southern Texas south through the Mexican States of Tamaulipas and Nuevo Leon. South of these regions and through Central America, G.b. ridgwayi replaces G.b. cactorum (Fisher 1893a, Friedmann and others 1950, Johnsgard 1988, Karalus and Eckert 1974, Oberholser 1974, Phillips and others 1964, van Rossem 1937, Schaldach 1963, de Schauensee 1966). In Arizona, its range is limited to Sonoran desertscrub and riparian habitats below 1220 m (4000 ft) in elevation in central and southern Arizona.

Ecology: Pygmy-owls are considered non-migratory throughout their range, having been reported during the winter months at Organ Pipe (Johnson unpubl. data 1976, 1980, T. Tibbitts pers. comm. 1997), Rillito Creek near Camp Lowell at present-day Tucson (Bendire 1888), and Sabino Canyon (USFS unpubl. data). Currently, the earliest nesting record in Arizona is from the collection of five eggs on April 12^th , recorded in the United States National Museum (USNM 1996). Due to the small population size and secretive nature of Cactus Ferruginous Pygmy-Owls in Arizona, information is limited. However, recent studies in Arizona have documented copulation on March 31, with egg laying estimated to have taken place between April 6 and April 11, 1996. Working backwards from a confirmed fledging event, the latest record of egg laying is estimated to have been between May 31-June 5 in Tucson, Arizona (Abbate and others 1996). Cactus Ferruginous Pygmy-Owls nest in a large cavity in a tree or large columnar cactus. These cavities may be naturally formed (e.g. knotholes) or excavated by woodpeckers. Nest lining material may or may not be used. Cavities are variously lined with nesting materials or left unlined (Abbate and others 1996, Breninger 1898, Proudfoot 1996). Juveniles remain in close proximity to adults until dispersal. While data is limited, studies indicate that juvenile Cactus Ferruginous Pygmy-Owls have dispersed at least four miles in Texas and two miles in Arizona from their natal sites before establishing their own territories (Proudfoot 1996, S. Richardson pers. comm., AGFD 1997).

Habitat Requirements: In Arizona, the Cactus Ferruginous Pygmy-Owl is primarily associated with the Arizona Upland Subdivision of the Sonoran Desert, below (1220 m) 4000 ft in elevation. Generally, vegetation at these sites includes both species and structural diversity, with well-developed ground cover, mid-story, and canopy layers. The density of the vegetation is likely required to provide an adequate prey base for the Cactus Ferruginous Pygmy-Owl, as well as cover from aerial predators. In riparian areas, plant species may include Fremont cottonwood, willow species, hackberry, and mesquite species. Within Sonoran desertscrub, plant species generally include saguaro, mesquite, paloverde, and ironwood. While the Cactus Ferruginous Pygmy-Owl was historically considered to be a riparian species, little is known about its use of standing water. For Cactus Ferruginous Pygmy-Owls occurring in Sonoran desertscrub, only three observations of direct water use by pygmy-owls for drinking or bathing have been documented (Abbate and others 1996). Cactus Ferruginous Pygmy-Owls within the Tucson, Arizona area, as well as some of those at Organ Pipe Cactus National Monument, occur in close proximity to residential developments in low density housing areas not exceeding one house per 3.3-40 acres where those developments occur adjacent to larger, undeveloped tracks of desertscrub habitat (M. Richardson pers. comm., USFWS 1997).

Management Issues with Conservation Recommendations

The lack of natural history information for this species has made species management difficult. Riparian and Sonoran desertscrub habitat losses are considered a primary factor in the decline of this species, as well as an on-going threat (Abbate and others 1996, Bahre 1991, Brown and others 1977, Rea 1983, Stromberg 1993, Stromberg and others 1992, Szaro 1989, Willard 1912). Current development pressure around major metropolitan areas, such as the city of Tucson, is resulting in on-going habitat losses (Abbate and others 1996, M. Richardson pers. comm., USFWS 1997). Additionally, increased recreational use and an invasion of nonnative grasses in Organ Pipe Cactus National Monument, increases the risk of habitat loss through wildfire (H. Smith in litt. 1996).

Cactus Ferruginous Pygmy-Owl management issues are listed in italics. Below each issue are Arizona Partners in Flight Conservation Recommendations.

Implementation Opportunities

Associated Species: Other species that may use similar habitat components or respond positively to management for Costa’s Hummingbird are: Ladder-backed Woodpecker, Curve-billed Thrasher, Ash-throated Flycatcher, Verdin, Black-tailed Gnatcatcher, Cactus Wren, White-winged Dove, Phainopepla, and Scott’s Oriole.

Distribution: The Costa's Hummingbird occurs in most of the lower Sonoran and limited portions of the upper Sonoran life zones of western North America. It is much less common but widespread in the Mohave desertscrub habitat (Baltosser and Scott 1996). Geographically, this translates primarily to western Arizona, southern California and limited portions of Nevada and Utah. In California, Costa’s Hummingbird habitat extends as far north as Santa Barbara County along the coast; inland the northern extension coincides with the Mohave desert range extending east into southern Nevada to the Utah border. The range extends south through the western half of Arizona and into the western half of the States of Sonora and Sinaloa in Mexico. The breeding range extends further south in Baja covering the entire peninsula as well as all the islands in the Gulf of California larger than 30 km² (Baltosser and Scott 1996). The non-breeding range remains unchanged south of the Mexican border, with the exception of a southward extension along mainland Mexico to the State of Jalisco. North of the border, the wintering range for Costa’s Hummingbird shrinks south and west withdrawing from Nevada and concentrating along the western Arizona border except for pockets around Phoenix and Tucson. Within California, the range shrinks southward along the coast.

Within Arizona, breeding habitat for the Costa’s Hummingbird stays strictly within the Sonoran desertscrub habitat, rarely exceeding 1000 m in elevation. This coincides primarily with southwestern and southcentral Arizona. Breeding occurs in the Mohave desertscrub along the Nevada border and lower Grand Canyon region and a few scattered sites in southeastern part of the State (Baltosser and Scott 1996). Postbreeding range recently reconfirmed to include lower slopes of Huachuca Mountains (S. Williamson and T. Woods in litt.) and the upper San Pedro River (D. Krueper pers. comm.). Wintering range also in Sonoran desertscrub habitat.

Ecology: Most birds arrive in desert in October/November wintering locally in desertscrub habitat; increasing in numbers and range until they reach the peak of breeding activity in March/April (Baltosser and Scott 1996). Most birds leave desert areas by May-June or earlier (Baltosser and Scott 1996, Monson and Phillips 1981). From June through August, limited numbers of Costa’s Hummingbirds can be found in the lower elevations in the mountain foothills. The earliest known nesting date was January 29 (nest with eggs) while the latest evidence was nest building on June 3 (ABBA unpubl. data).

Costa’s Hummingbirds have been recorded nesting predominately in southwestern and southcentral Arizona below 3300 ft. Fewer records have been recorded from the SE quadrant of the State. Nesting has been confirmed north of Phoenix southeast to Tucson. In addition, breeding has been confirmed in isolated locations such as the Grand Canyon and the extreme southeastern corner of the State (near the New Mexico border) (ABBA unpubl. data). No breeding has been recorded in the NE quadrant of the State (ABBA unpubl. data).

Costa’s Hummingbirds typically build nests in a shrub or tree approximately 1-2 m above ground; the support structure can be living or dead and considerable variation occurs among habitat types. In Arizona, the most common nest plant is foothill paloverde, followed by jojoba, blue paloverde, ironwood, canyon ragweed, hopbush and goldenweed (ABBA unpubl. data, Baltosser and Scott 1996). The nest is composed primarily of small pieces of plant material and feathers fastened with spider web (Baltosser and Scott 1996). Plant material can include bark, small leaves, flower bud scales, ball-like flower heads, bits of lichen, dandelion or thistle heads, and other downy material.

Primarily nectar feeders, the two most important plant species for the Costa’s Hummingbird are chuparosa and ocotillo. Chuparosa has a lengthy flowering period and is the most reliable and productive of midwinter nectar sources (Scott 1994). Some populations can flower for 6 months from fall through spring breeding period (Baltosser and Scott 1996, Rea 1983, Weathers 1983). Ocotillo has a much shorter (3-4 week) but predictable flowering season in March/April (Baltosser and Scott 1996, Waser 1979). Other nectar sources include: desert lavender, thornbush (Lycium), creosotebush, fairy duster, foothill paloverde, saguaro, desert willow, ironwood, desert honeysuckle, barestem larkspur and Mojave beardtongue (Baltosser and Scott 1996). Although there is little information, all hummingbirds (including Costa's) supplement their diet with insects presumably to satisfy protein requirements. Female hummingbirds require additional protein during egg-laying and when feeding young (Brice and Grau 1991).

Habitat Requirements: Costa’s Hummingbirds breed primarily in Sonoran desertscrub habitat and within the United States, Arizona has the greatest concentration of desertscrub (Shreve and Wiggins 1964). Only the State of Sonora, Mexico, has a higher percentage of desertscrub habitat. In Arizona, Costa’s Hummingbirds occur along desert washes, bajadas or mesa's. They are extremely xerophilous (adapted to hot, dry environments). Baltosser and Scott (1996) described the following three plant associations where Costa's can be found: 1) dry washes lined with foothill paloverde, blue paloverde, catclaw acacia, ironwood, and smoketree or filled with shrubs such as creosotebush, jojoba, desert lavender and chuparosa; 2) steep rocky slopes with ocotillo and foothill paloverde; 3) gently sloping bajadas covered with saguaro, creosotebush, and cholla cacti. Costa’s Hummingbirds select drier desertscrub even when adjacent to riparian habitat (Brown 1992, Szaro and Jakle 1985). Winter flowering of a few key species such as chuparosa my be crucial, allowing Costa’s Hummingbird to persist with little interference from other hummingbird species (Baltosser and Scott 1996).

Population levels for Costa’s Hummingbirds are relatively stable and the bird is still common throughout much of its' range (Baltosser and Scott 1996). However, the Sonoran desertscrub which constitutes the primary habitat for the Costa’s Hummingbird is facing increasing threats from habitat modification (Baltosser and Scott 1996). Urbanization is increasing at an alarming rate and the Costa's appears to have limited adaptive capability to non-native vegetation and hummingbird feeders (Baltosser and Scott 1996). Whether this is due to direct competition with the more aggressive Anna's Hummingbird or other reasons is unknown. Grazing is a second impact to desertscrub habitat. Grazing impacts on the Costa’s Hummingbird are unknown; although some nectar plants are thorny and resistant to grazing, shrub seedlings and herbs can be affected (Baltosser and Scott 1996). Similarly, browsing by feral burros, especially of foothill paloverdes, may greatly reduce Costa’s preferred nesting substrate. Fire is a third element to impact the Costa's habitat. The introduction of non-native grasses into desertscrub habitat has increased fire potential. The desertscrub habitat is not fire-adapted and many tree species used for nesting are impacted. On the other hand some forage species such as chuparosa appear to respond well to fire (Baltosser and Scott 1996). Although current population trends for the Costa’s Hummingbird are stable; the exponential rate of desertscrub habitat conversion raises concerns for the future stability of species dependent upon Sonoran desertscrub habitat.

Costa’s Hummingbird management issues are listed in italics. Below each issue are the Arizona Partners in Flight Conservation Recommendations.

Fire

Associated Species: Other species that may use similar habitat components or respond positively to management for the Gilded Flicker are: Purple Martin, Brown-crested Flycatcher, American Kestrel, Ash-throated Flycatcher, Verdin, Western Screech-Owl, Elf Owl, White-winged Dove, Gila Woodpecker, and Scott’s Oriole.

Distribution: The Gilded Flicker is resident from extreme southeastern and Baja California, southeastern Nevada, through central Arizona to northwest Mexico (Sonora and Sinaloa) from sea level to about 900 m (2955 ft). Throughout most of their range, Gilded Flickers are confined to desert scrub with large cacti (saguaro, organ pipe, cardon and hecho). In the northeastern portion of their range (southeastern and central Arizona) Gilded Flickers use riparian woodlands (cottonwood/willow) where large cacti are absent.

Ecology: The nesting period spans from February to June with nests frequently found in the upper 3 m (10 ft) of a giant cactus (Winkler and others 1995). Nest heights range from 2.5-12 m (8-40 ft), generally around 4.5 m (15 ft) (Bent, 1939). Cottonwoods, willows and snags are used where giant cacti are absent. From 3 to 5 eggs are laid indicating a lower reproductive rate than Northern Flicker (Colaptes auratus). Old nests are used by other species such as flycatchers and owls. Food includes ants and their larvae, other insects and fruit (e.g. cactus fruits). Flickers may cause some damage to pecan and walnut plantations (Winkler and others 1995). Gilded Flickers "suffer greatly from nest competition from" European Starlings (Sturnus vulgaris) (Winkler and others 1995).

Habitat Requirements: In Arizona the Gilded Flicker is primarily associated with saguaro and to a lesser extent with cottonwood at the edges of its range. Saguaros provide nesting substrate and food. Populations are densest where saguaros are abundant.

The spread of European Starlings into the desert Southwest has apparently caused declines in Gilded Flicker populations due to their intense competition for nest cavities. Large scale removal of desert scrub vegetation for subdivisions and agriculture, and the lack of recruitment of saguaros, has eliminated habitat for this species. Increased urbanization has, in some instances, increased the negative publicity towards woodpeckers in general due to their noisy vocalizations and destruction of expensive, planted saguaros. Conversion of cottonwood/willow riparian habitat to agriculture and invasion of the exotic salt cedar has likewise reduced the amount of habitat available, especially along the Colorado River. The spread of non-native grasses into desert scrub habitats has introduced fire where plants are not fire-adapted causing conversion from shrublands to grasslands. This is particularly true in Sonora where over 10% of the total land surface has been converted to non-native buffel grass spp. The rapid spread of red brome into Arizona desertscrub presents a similar threat.

Gilded Flicker management issues (potential) are listed in italics. Below each issue are the Arizona Partners in Flight Conservation Recommendations.

Fire

Associated Species: Other species that may use similar habitat components or respond positively to management for the Rufous-winged Sparrow are: Cactus Wren, Curve-billed Thrasher, Black-throated Sparrow, Verdin, Black-tailed Gnatcatcher, Phainopepla, Pyrrhuloxia, and Northern Cardinal.

Distribution: In the United States, the Rufous-winged Sparrow is resident only in southcentral Arizona. It then occurs south through Sonora to central Sinaloa in Mexico. In Arizona it ranges from near Winkelman and southwest of Florence, southeast to Mammoth, and south to Nogales and west through the Tohono O’odham Nation and the Sauceda Mountains in Maricopa County (Monson and Phillips 1981; Arizona Breeding Bird Atlas, unpublished data). During eruptions, the Rufous-winged Sparrow has been found east to Sierra Vista, Tombstone and Saint David, Elgin and Gardner Canyon wash east of the Santa Rita Mountains, and west to Quitobaquito (Monson and Phillips 1981).

Ecology: The Rufous-winged Sparrows is non-migratory. It may be heard singing any time of the year, but in normal (dry) years, singing occurs from June or July to mid-September (Bent 1968). Territory size varies depending on resource availability and range from less than 0.5 ha (1 ac) to more than 1 ha (2 ac) per pair (Phillips in Bent 1968). Rufous-winged Sparrows have been found nesting from mid-April to mid-September with the bulk of nesting after initiation of summer rains in July. April and May nesting likely occurs only during those years with higher precipitation during the winter and early spring (ABBA unpubl. data, Bent 1968). Nests are often placed in desert hackberry, graythorn, cholla, mesquite, and clumps of mistletoe in paloverde between 0.15-2.5 m (0.5-8.2 ft) (Phillips in Bent 1968). In riparian and mesquite dominated habitats, cowbird brood parasitism has been as high as 50 percent (Bent 1968). During the nesting season a large proportion of the food includes small caterpillars and grasshoppers. They also catch low-flying insects in short sallies and glean others from the stems of small plants such as burroweed (Bent 1968). Food at other seasons presumably consists largely of grass and weed seeds (Bent 1968).

Habitat Requirements: Phillips (in Bent 1968), characterizes the habitat of Rufous-winged Sparrow as grass and thorny brush. This includes lush Sonoran Desert and washes with palo verde, ironwood, mesquite, desert hackberry, cholla, saguaro, burroweed and scattered grasses, as well as, semidesert grassland mixed with shrubby mesquite and acacia (Bent 1968). Rufous-winged Sparrows formerly preferred the Sonoran Savanna Grassland (Brown 1982), a habitat that has undergone a drastic reduction in Arizona and Sonora. It will also use shrub-dominated, former cropland and riparian bottomland, as long as grass is a major component (Phillips in Bent 1968). This species seems to prefer the flatter portions of the habitat and apparently does not use the steeper hillsides. Formerly more common in the Tucson Basin, Rufous-winged Sparrows disappeared for nearly 50 years from that area as a result of overgrazing (Phillips and others 1964). They were rediscovered in the Tucson Basin in 1936.

Conservation of the Rufous-winged Sparrow requires protection of grassland habitats particularly in core areas. While formerly common throughout the Tucson Valley, much of the core area for Rufous-winged Sparrow has been converted into urbanized habitats. Substantial portions of Rufous-winged habitat are subject to future development. Tubac Rita Ranch and other developments north of Nogales will also displace birds, therefore core areas will become of increasing importance in the future. Improper grazing that reduces or eliminates prime grass habitat will negatively effect Rufous-winged Sparrow population numbers and is strongly discouraged. Restrictions on floodplain development and retention of natural plant communities in floodplains will contribute positively to the conservation of this species.

Rufous-winged Sparrow management issues are listed in italics. Below each issue are the Arizona Partners in Flight Conservation Recommendations.

Habitat Loss/Alteration

Implementation Opportunities:

Associated Species: Other species that may use similar habitat components or respond positively to management for the Le Conte’s Thrasher are: Lesser Nighthawk, Black-throated Sparrow, Black-tailed Gnatcatcher, Verdin, Loggerhead Shrike, and Greater Roadrunner.

Distribution: The Le Conte’s Thrasher’s breeding range currently extends from Southern Nevada and Southwestern Utah to Southeastern California and Western/Southwestern Arizona, northeastern Baja and northwestern Sonora (AOU 1983, Sheppard 1996). This thrasher in uncommon and local throughout its range and is not known to be migratory (Phillips and others 1964, Rosenberg and others 1991, Sheppard 1996). Earlier accounts have documented the Le Conte’s Thrasher in Central and parts of Southeastern Arizona as well (Mearns 1886, Merriam 1895).

Ecology: Nesting generally occurs from February to June (Gilman 1904, Sheppard 1996) and several clutches are raised (Ehrlich and others 1988). Nests built of twigs and lined with two layers of flowers and fibers are commonly found in dense cholla cactus, creosote and palo verde (Ehrlich and others 1988, Gilman 1909, Merriam 1895).

Habitat Requirements: Nearly all Toxostoma species occur within the Colorado River basin (Mearns 1886). Le Conte’s Thrasher inhabits sandy desert washes, flats and dunes (Phillips and others 1964, Rea 1983). Surrounding vegetation is typically Ambrosia/Atriplex with some Prosopis and Cholla species (Rea 1983). Along the Gila River, areas inhabited by Le Conte’s are mostly dominated by creosotebush (Monson and Phillips 1964). The Le Conte’s Thrasher is the only avian species diagnostic of this sparsely vegetated Lower Colorado River Valley Subdivision of Sonoran Desertscrub (Brown 1994). This species forages entirely under desert shrubs (Sheppard 1996). Comparatively, the Crissal Thrasher (T. crissale) is common to dense Prosopis stands and forages within the branches of these bushes as well (Gilman 1909, Rea 1983).

Very little is known about the biology/ecology of the Le Conte’s Thrasher. The decline of this thrasher’s breeding range is largely attributed to habitat degradation involving the destruction of substrate, litter and shrubs. Shooting (near urban areas), DDT spraying (primarily in Mexico) and the improper use of some types of mist nets by ornithologists (60 mm mesh) may also be important factors in the decline of this species (Sheppard 1996). The Le Conte’s Thrasher has been designated as a Species of Special Concern by the California Department of Fish and Game and as a Category 2 candidate for possible listing by the USFWS (Sheppard 1996). Management recommendations would involve setting aside large areas of appropriate desert habitat. Although no steps have been taken to set aside habitat for this species, many conservation areas currently in existence and in planning may also meet the needs of Le Conte’s Thrasher (Sheppard 1996).

Le Conte’s Thrasher management issues are listed in italics. Below each issue are the Arizona Partners in Flight Conservation Recommendations.

Associated Species: Other species that may use similar habitat components or respond positively to management for the Purple Martin are: Brown Crested Flycatcher, Gila Woodpecker, Gilded Flicker, American Kestrel, Northern Cardinal, House Finch, Elf Owl.

Distribution: The Purple Martin breeds from southwestern British Columbia south to Baja California; and from northeastern British Columbia to New Brunswick south to Mexico, the Gulf Coast, and southern Florida. Local in the Rocky Mountains but avoids most other mountainous areas (DeGraff and others 1991). Winters in South America east of the Andes from Venezuela south to northern Bolivia and southeastern Brazil (Ehrlich and others 1988). In Arizona, breeds in the Transition Zone of open habitats of the entire Mogollon Plateau region, extending to Williams, Mount Trumbull, the Natanes Plateau, the Sierra Ancha, and the Prescott region. Also found in the Chiricahua Mountains but absent from other mountains of southern Arizona, the Grand Canyon, and the northeast. Also in saguaro associations of south-central Arizona west to the Ajo Mountains and north to near Picacho, Florence, Roosevelt Lake, and the lower San Pedro Valley. Rare outside the breeding ranges (Phillips and others 1964).

Ecology: Purple Martins arrive in Arizona in early April and remain until early October (Phillips and others 1964). In the Arizona Upland subdivision of the Sonoran Desert, Purple Martin’s nest primarily in old woodpecker holes in larger and older saguaros (Phillips and others 1964). Most nests are placed in the main stem of the saguaro within 3 m of the top (Brown 1997) and no more than one pair per saguaro has been found in Arizona (Brown 1997). Purple Martins also nest in tree cavities excavated by woodpeckers, and occasionally in cliff niches. They use colonial birdhouses in the eastern United States but have not adapted to these in the west, where they tend to nest singly (Brown 1997, Phillips and others 1964). The nest is made up of grass, leaves, mud, feathers, and occasionally has a dirt rim to keep eggs from rolling out. Fresh green leaves added during incubation are thought to be used for their pesticidal properties. Cowbird parasitism is very rare.

Purple Martins feed on flying insects taken on the wing often at altitudes over 50 m (164 ft), and may occasionally feed on the ground. Food items include ants, wasps, beetles, grasshoppers, stink bugs, treehoppers, dragonflies, moths, butterflies, mosquitoes, horseflies, robber flies, etc. Typically, they don’t forage when temperatures are less than 9° C (48° F) or in the rain. If cold or adverse weather lasts more than 3-4 days, mortality can be substantial (Brown 1997). They drink and bathe on the wing (Ehrlich and others 1988). They gather in enormous premigratory communal roosts at the end of summer, which may include up to 100,000 birds (Ehrlich and others 1988).

Considered as two subspecies in Arizona, exhibiting ecological races. Martins inhabiting the saguaro deserts (P.s. hesperia, used tentatively by Phillips, 1964) are of decidedly smaller size than those found in north and central Arizona (P.s. arboricola). The two habitats (and distributions) are in close proximity in the Roosevelt and Coolidge Lake areas.

Habitat Requirements: Purple Martins in the Upper Sonoran Desert are closely associated with saguaro forests. They will forage and roost in areas adjacent to cactus forests, including towns, parks, lakes and ponds. In central and southeastern Arizona, Martins inhabit open and cut over woodlands, open grassy river valleys, meadows around pools, shores of lakes, marsh edges, agricultural lands, parks and towns. Where trees are the nesting substrate, they prefer stands with both living and dead trees (Brown 1997). Purple Martins need a high old-growth snag density adjacent to or in open areas preferably near open water.

Management Issues with Conservation Recommendations

Audubon Society Blue List 1975-1981, Special Concern 1982-1986. Increased development and fire in Upland Sonoran Desert habitat could pose threats to P.s. hesperia, by reducing nest site availability in large saguaro forests. Forestry practices that removed standing dead trees greatly reduced the availability of natural nest sites for P.s. arboricola. Since they do not use colonial nest boxes in western states, they suffer from a lack of nest sites in many areas. House sparrows and starlings compete for nest cavities and can cause local extirpation. Brawn and Balda (1988) state that the Purple Martin has nearly been extirpated from the ponderosa pine forest since fire suppression has resulted in much denser conditions and logging has reduced the number of snags and large old trees. Currently nests only in clusters of old, dead pines containing numerous woodpecker holes. Pesticide use in South America is a potential threat to wintering birds.

Purple Martin management issues, in Upland Sonoran Desert habitat, are listed in italics. Below each issue are the Arizona Partners in Flight Conservation Recommendations.

Habitat Loss

EVALUATION OF ASSUMPTIONS: RESEARCH AND MONITORING