Associated Species: Other species that may use similar habitat components or respond positively to management for the Gray Flycatcher are: Plumbeous Vireo, Juniper Titmouse, Bewick’s Wren, Pinyon Jay, Western Scrub-Jay, Black-throated Gray Warbler, Ash-throated Flycatcher, Western Bluebird, and Scott’s Oriole.

Distribution: The Gray Flycatcher breeds in western North America from extreme southern British Columbia (Okanagan Valley), southcentral Washington, central and eastern Oregon, south-central Idaho, and southeastern Wyoming south through western and southern Colorado, eastern California, northern and east-central Arizona, and western New Mexico (AOU 1983). In Arizona, it breeds from the Arizona Strip region and the Navajo and Hopi nations south and east to the Bradshaw Mountains and northeastern Graham and central Greenlee Counties (McCarthey and Corman 1996). Its wintering grounds extend from southeastern California and central Arizona south along the Pacific Slope and interior of Mexico to Nayarit, southern Baja California, and Oaxaca (Howell and Webb 1995). In Arizona, it winters locally along the lower Colorado River, near the town of Kirkland, in the lower Verde River drainage south and east to the town of Sasabe, along the San Pedro River Valley, and very locally to the base of the Chiricahua Mountains (Monson and Phillips 1981).

Ecology: In Arizona, spring migration begins in late March, peaks in late April and early May, and continues with stragglers (rarely) to late May. The primary food for Gray Flycatchers are insects, including: butterflies, moths, bees, grasshoppers, and beetles. The scanning perches are on top of shrubs or small trees, and the flycatching airspaces are close to the ground. The flycatcher often will capture insects on the ground or on low plants (Ryser 1985). From late May through July, nests are placed primarily 0.6 - 3.4 m (2 - 11 ft) high in a shrub or crotch of a juniper or pinyon pine (Terres 1980; ABBA unpubl. data). When nesting in juniper woodlands, the nest is largely made of strips of juniper bark and is therefore well camouflaged (ABBA unpubl. data). Estimated density of Gray Flycatchers ranges from 19-29 pairs per 100 ha (247 ac) (T.W. Haislip in Friedmann and others 1977; LaRue 1994). T.W. Haislip (in Friedmann and others 1977) documented moderate Brown-headed Cowbird nest parasitism in local populations in Oregon. In Arizona, fall migration begins in mid-August and continues through mid-October.

Habitat Requirements: Gray Flycatchers breed in semi-arid woodlands and brushy areas that include pinyon pine and/or juniper woodlands, tall sagebrush/greasewood plains, and open ponderosa or Jeffrey pine forests with pinyon and/or juniper understory. Nesting elevations range from approximately 1400-2300 m (4500-7500 ft), very locally to 2750 m (9000 ft) in Arizona (C. LaRue pers. comm.) and 3350 m (11,000 ft) in California (Small 1994). In Arizona, Gray Flycatchers are most common in larger and taller stands of pinyon pine and/or juniper with open understory sometimes interspersed with sagebrush, cliffrose, and barberry (ABBA unpubl. data). They may need some ground cover to support insect populations for foraging. Gray Flycatchers winter in arid scrub, edge or open riparian woodlands, and mesquite bosques usually below 1400 m (4500 ft) in Arizona.

Management Issues with Conservation Recommendations

Breeding habitat loss and modification of Pinyon-Juniper woodlands has occurred through chaining, clearing, and burning of large, mature woodland tracts for livestock and ungulate forage, house and road development, and fuelwood cutting. Overgrazing by elk and livestock reduces groundcover, inhibits regeneration of shrubs, and increases local cowbird populations. Unitt (1987) suggests there may be an increase in cowbird nest parasitism rates of Gray Flycatchers which may become a serious problem in the future. In Arizona, winter habitat loss includes removal of large tracts of pinyon-juniper woodlands for agriculture, grazing, and fuelwood cutting. Possible threats on wintering grounds in Mexico are largely unknown.

Gray Flycatcher management issues are listed in italics. Below each issue are Arizona Partners in Flight Conservation Recommendations.

Commercial Operations

1. Consider habitat needs in agency plans and projects, including stewardship projects.

Associated Species: Other species that may use similar habitat components or respond positively to management for the Pinyon Jay are: Hairy Woodpecker, White-breasted Nuthatch, Northern Flicker, Cassin’s Kingbird, Mountain Chickadee, Clark’s Nutcracker (foraging).

Distribution: Range of the Pinyon Jay is tied primarily to the distribution of pinyon-juniper woodlands of the Southwest and Intermountain regions of the United States. They breed as far north as central Montana and south to Baja California (Balda and Bateman 1971, Ligon 1978, Marzluff and Balda 1992). In Arizona, Pinyon Jays are permanent residents of pinyon-juniper woodlands and lower ponderosa pine forests in the northern and central part of the state (Balda and Bateman 1971), ranging east to Natanes Plateau, west to the Hualapai Indian Reservation, south possibly to Prescott area, and north to Mount Trumbull (Phillips and others 1964). Pinyon Jays are nonmigratory but may exhibit irregular nomadic movements of hundreds of miles outside normal range during fall and winter when pine seed crops are poor (Balda and Bateman 1971, Phillips and others 1964, Westcott 1964).

Ecology: Pinyon Jays are very early nesters, initiating egg-laying as early as February. Typically, they nest in pinyon-juniper woodlands but will also nest in ponderosa pine forests (approx. 2135 m (7000 ft), Balda and Bateman 1971, Marzluff and Balda 1992). Large flocks (up to 250 individuals) nest communally in traditional breeding areas. Courtship begins in November and pairs form in January-February. Pair bonds are long-term and mates interact throughout the year (Balda and Bateman 1971). Highly synchronous flock nest building begins late February to mid-March. Females incubate, but both parents feed nestlings. Older fledglings are fed by parents and helpers. Young attain independence at 16 weeks. Pairs will renest up to five times in a breeding season if earlier nesting attempts fail (Marzluff and Balda 1992). Most birds breed at age two and have an average lifespan of five years (Marzluff and Balda 1992).

Breeding is apparently triggered by abundant pinyon pine seeds which are harvested in fall and early winter and cached in breeding areas for use during late winter and early spring. Pinyon pine seeds provide the primary source of reproductive energy for nesting Pinyon Jays (Balda and Bateman 1971, Marzluff and Balda 1992). In years following poor pinyon production, breeding is delayed until April or May when other foods, primarily insects, become common (Ligon 1971). Pinyon Jays will also feed on ponderosa pine seed, fruits, eggs, nestlings, lizards. They feed on the ground, in foliage and hawk for insects (Balda and Bateman 1971).

The Pinyon Jay is a gregarious and highly socialized species. Large, highly integrated flocks are maintained year-round and use well-defined home ranges during most years. During poor seed crop years, individuals and flocks have been observed in southern Arizona as well as at treeline in northern Arizona harvesting limber pine seed (Phillips and others 1964, Westcott 1964, Balda and Bateman 1971). Largest flocks (100s to over 1000 birds) (Bent 1964) seen in late summer and winter.

Habitat Requirements: Food availability seems to be the most important factor determining colony breeding site selection (Gabaldon 1979). Open cup nests (usually one nest/tree) are placed in ponderosa pine, pinyon pine, Gambel’s oak, juniper, and occasionally blue spruce trees. Nests are typically 1-8 m (3-26 ft) high and tend to be south-facing (Gabaldon 1979, Marzluff and Balda 1992). Gabaldon (1979) found nest trees were taller and had higher foliage density than surrounding trees. Gabaldon (1979) also found jays avoided trees with abundant pine cones, perhaps because these might attract predators. Many nests were located along roads and Gabaldon (1979) found these nests to have higher reproductive success. Balda and Bateman (1971) studied a well defined flock of about 250 birds which maintained a 21 km² (8 mi²) home range which included ponderosa pine forest, pinyon-juniper woodland and grassland. This flock used a traditional nesting area of about 95 ha (230 ac) (Balda and Bateman 1971).

Communal seed caching areas are discrete and located within a flock’s home range. Generally, cache sites are sparsely vegetated, have good drainage and a southern exposure. Thus, these areas are snow-free or first to melt. Birds also tend to cache seeds close to tree trunks where less snow accumulates. Not only do these sites allow for easy retrieval of cached seeds during the early nesting season, but they also provide good conditions for seed germination. Many cached seeds are not consumed and germinate (Ligon 1971). Balda (1987:525) described the relationship between the pinyon jay and pinyon pines as "...one of the best coevolved, mutualistic plant-vertebrate examples known...".

According to Breeding Bird Survey data, Arizona had the highest average statewide density for the Pinyon Jay from 1965-1979 (Robbins and others 1986). However, analyses of these data did not reveal any significant trends for this species. Balda and Marzluff’s (1992) data for an intensively studied pinyon jay population in Flagstaff, from 1972-1986, indicated a declining population.

Three major factors, which vary annually, affect the long-term success of Pinyon Jay populations: size of pinyon pine crops, amount of nest predation, and harshness of the physical environment, particularly the amount of snow during the nesting season (Marzluff and Balda 1992). Although we have no control over the latter, the first two factors can be influenced by human activities. Primary management concerns related to these include: 1) habitat loss due to urbanization, as documented in the Flagstaff vicinity (Marzluff and Balda 1992), as well as to management of pinyon-juniper woodlands (e.g. chaining, burning) and potential habitat loss from Ips beetle invasion of stressed pinyon trees, 2) abundance of mature pinyon pine trees which provide the primary source of food for breeding pinyon jays and which can also be affected by land management practices, and 3) increasing numbers of American Crows and Common Ravens (important nest predators) in Pinyon Jay breeding areas near urban areas (also documented in the Flagstaff area) (Marzluff and Balda 1992).

Pinyon Jay management issues are listed in italics. Below each issue are the Arizona Partners in Flight Conservation Recommendations.

Outreach Needs

Associated Species: Other species that may use similar habitat components or respond positively to management for the Gray Vireo are: Ash-throated Flycatcher, Juniper Titmouse, Bushtit, Bewick’s Wren, Blue-gray Gnatcatcher, Black-chinned Sparrow, and Scott’s Oriole.

Distribution: The Gray Vireo breeds from Southern California (locally) and northwestern Baja California, southern Nevada, southern Utah, and southern Colorado south through western and central New Mexico, and isolated localities in the Texas and Oklahoma panhandles, and also southwestern Texas and northwestern Coahuila (A.O.U. 1983, Small 1994, Andrews and Richter 1992, Wauer 1973, Phillips and others 1964). In Arizona, Gray Vireos breed at mid-elevations from the Grand Canyon region east across the Navajo Nation and south through the Mogollon escarpment into the southeastern portions of the state (ABBA unpubl.data, Brown and others 1984, LaRue in prep, Phillips and others 1964). Gray Vireos are rare migrants throughout the state (Brown and others 1984, Phillips and others 1964). They winter mainly in northern Mexico, southern Baja California and rarely in southern Arizona and the Big Bend region of Texas (AOU 1983, Howell and Webb 1995, Wauer 1973).

Ecology: The Gray Vireo arrives in southern Arizona in early April and northern Arizona in late April. They depart these regions in early and late September respectively (LaRue in prep, Phillips and others 1964). Gray Vireos are primarily insectivorous during the breeding season. During the winter, they are frugivorous and rely almost entirely on fruit of elephant trees (Bates 1992). They typically nest low in a small tree or shrub 0.5-2.0 m (2-6 ft) above ground (Ehrlich and others 1988). Young fledge at 13-14 days. Gray Vireos are known hosts of the Brown-headed Cowbird. Gray Vireos tend to occur at naturally low population densities.

Habitat Requirements: Gray Vireos breed in Arizona in open mature pinyon-juniper woodlands on canyon and mesa slopes from 975-2075 m (3200-6800 ft) in elevation. A broadleaf shrub component is typically present, often comprised of Utah serviceberry and single-leaf ash. Gray Vireos may also breed in situations dominated by a chaparral component (T. Corman, AGFD, pers. observ.). In northeastern Arizona, they were absent from woodland stands greater than 280 trees/ha (2.5 ac) (LaRue 1994).

Apparently some population declines of Gray Vireos have been noted in California (Small 1994) and the species is on Arizona’s Wildlife of Special Concern list (AGFD 1996 draft). Although it is a known cowbird host, no negative impacts have been clearly identified at this time. The apparent extreme winter dietary specialization as well as the tendency to occur in low densities, confers some intrinsic vulnerability which could result in population declines. Because of their tendency to occupy undisturbed canyon and mesa slopes, Gray Vireos may be relatively immune to habitat-related population declines. In general, life history of the Gray Vireo is still poorly known.

Gray Vireo management issues are listed in italics. Below each issue are the Arizona Partners in Flight Conservation Recommendations.

Fire Suppression

Associated Species: Other species that may use similar habitat components or respond positively to management for the Black-throated Gray Warbler are: Plumbeous Vireo, Juniper Titmouse, Bewick’s Wren, Pinyon Jay, Western Scrub-Jay, Ash-throated Flycatcher, Western Bluebird, and Scott’s Oriole.

Distribution: The Black-throated Gray Warbler’s breeding range extends from southwestern British Columbia south through the coastal states to northern Baja California. Eastward it extends from eastern Oregon through southern Idaho and Wyoming south to southeastern Arizona, southwestern New Mexico, extreme west Texas (breeding status unknown in Guadalupe Mountains), and northeastern Sonora, Mexico (Dunn and Garrett 1997, Guzy and Lowther 1997). The Black-throated Gray Warbler winters in Baja California, on the Pacific Slope and interior of Mexico, and in small numbers along the West and Gulf coasts of the United States (Guzy and Lowther 1997). In Arizona, this species is found breeding north of the Mogollon Rim and south through eastern Arizona, west to the Baboquivari and Bradshaw Mountains, Grand Canyon Region, and the Hualapai Mountains (ABBA unpubl. data, Monson and Phillips 1981). The Black-throated Gray Warbler is an uncommon winter resident in Phoenix, Tucson, and the Babaquivari Mountains (Monson and Phillips 1981).

Two races of Black-throated Gray Warblers are distinguished by differences in wing length, amount of white in tail, and song. Dendroica nigrescens nigrescens breeds from northwestern California to southwestern British Columbia, and D. n. halseii breeds in eastern Oregon and Washington south through Arizona, New Mexico, and Sonora, Mexico (Morrison 1990, Oberholser 1930). The former race winters in California and Arizona south to northern Mexico, while the latter winters only in Mexico (Morrison 1990). Some authors recognize these two races as distinct subspecies: genetic differences between Black-throated Gray Warblers of Washington and Arizona are as great as those between Townsend’s warblers and hermit warblers (Bermingham and others 1992).

Ecology: The Black-throated Gray Warbler is a short-to-medium-distance Neotropical migrant whose migration route follows the coast and mountain ranges of western North America (Curson and others 1994, Guzy and Lowther 1997). Spring arrival dates in southern Arizona range from mid-March through May, and departure dates range from late July through October. Spring arrival dates in northern Arizona range from mid-Aprilthrough May, and departure dates range from mid-July through early October (Phillips and others 1964). Nesting records from Arizona include: 12 nests with eggs found 4 May-19 June, with the majority of these nests found between 17 and 26 May (n = 7; Bent 1953); an occupied nest on 15 May 1993 in the Hualapai Mountains; a nest with young on 28 May 1995 in Coconino National Forest; and a nest with young on 10 July 1997 north of the Kaibab National Forest on the Arizona (ABBA unpubl. data). Breeding Bird Atlas data suggest that the Black-throated Gray Warbler’s breeding season begins in April in the southern part of their range (an adult was seen carrying food on 9 May 1993, and an adult was seen feeding recently fledged young on 19 May 1995) and extends into August (recently fledged young observed on 7 August 1996). The Black-throated Gray Warbler builds a deep cup nest of leaves, cocoons, oak mast, paper shreds, bark, and other plant material, and it is frequently lined with small feathers of other bird species (Harrison 1979). They typically raise one brood a year, though they may double-brood in some areas (e.g. Monterey County, California; Roberson and Tenney 1993).

The Black-throated Gray Warbler’s diet consists almost exclusively of insects, especially caterpillars (Dunn and Garrett 1997). They primarily forage at the mid-canopy level by gleaning foliage, or occasionally by hover gleaning and sallying for flying insects (Dunn and Garrett 1997). This species is not social during the breeding season, but will join mixed-species flocks with other insectivorous birds during winter and migration (Dunn and Garrett 1997). Known predators of adults include Sharp-shinned Hawks and Cooper’s Hawks (Reynolds and Meslow 1984), and likely predators of eggs and young include jays, crows, and snakes (Bent 1953, Grinnell and Storer 1924). There is little information on the extent which brown-headed cowbirds affect Black-throated Gray Warblers. Bent (1953) reported that brood parasitism was not a problem for this species, but recent reports suggest that parasitism rates are higher than previously thought or are increasing. Research from four different locales in the western United States suggests parasitism rates between 11% and 21% (see Guzy and Lowther 1997). Thirteen percent of Black-throated Gray Warbler family groups (n = 30) reported by the Arizona Breeding Bird Atlas (ABBA unpubl. data) had a fledgling cowbird.

Habitat Requirements: In northern Arizona, the Black-throated Gray Warbler is primarily associated with pinyon pine and juniper woodlands (occasionally with scattered ponderosa pine) and mixed oak-pine woodlands. In southern Arizona, this species occupies oak-alligator juniper woodland, Chihuahuan pine, Mexican pinyon pine, Emory oak, and Arizona white oak, as well as other mixed oak-conifer associations along canyons and steep slopes (Balda 1969, Dunn and Garrett 1997). Breeding habitat is frequently characterized by a brushy undergrowth of scrub oak, ceanothus, manzanita, or mountain mohagany (Dunn and Garrett 1997). During spring and fall migration, these warblers can be found in a variety of forest, woodland, scrub, and thickets similar to that used during the breeding season (AOU 1983), as well as desert washes and desert riparian areas (Troy Corman, pers. observ.). Individuals that winter in Arizona are primarily associated with cottonwood-willow and sycamore-mesquite vegetation (Monson and Phillips 1981). In addition, Black-throated Gray Warblers have become more common as winter residents in shade trees of urban areas, such as Phoenix and Tucson (Troy Corman, AGFD, pers. observ.).

Little information is available on microhabitat characteristics of nest sites. Nests are typically placed on a horizontal tree branch or near the main stem of a shrub (Harrison 1979). Of seven nests found in southeastern Arizona, six were in white or Emory oak and one was in juniper, average nest height was 7.5m (24.5 ft) (range 3.6-12.2 m or 12-40 ft), and nests were 1.2-3.0 m (4-10 ft) from the tree trunk (Harrison 1984). Other nests found in Arizona include one from the Chiricahua Mountains that was in a dense mistletoe clump, 0.46 m (1.5 ft) high and 0.86 m (3 ft) from the trunk of a scrub oak, and one from northern Arizona that was 3.25 m (10.5 ft) high in a juniper tree and 0.78 m (2.5 ft)from the trunk (ABBA unpubl. data).

There is little information on overall population trends for the Black-throated Gray Warbler. Breeding Bird Survey (BBS) data suggest steady or slightly increasing numbers from 1966-1991 (Peterjohn and others 1995). This species does not appear to be greatly impacted by human activities and will occupy areas that have been altered. However, there have been no detailed studies of responses to habitat alteration, such as changes in densities, breeding success, and habitat use (Guzy and Lowther 1997). Techniques used for improving pasturelands, such as the removal of overstory trees from pinyon-juniper woodland, may adversely affect habitat use by Black-throated Gray Warblers (Sedgwick 1987). Continued alteration and loss of habitat may have cumulative effects unidentified to date. For example, land management practices that increase contact between Black-throated Gray Warblers and brown-headed cowbirds may have a substantial impact on breeding success.

Black-throated Gray Warbler management issues are listed in italics. Below each issue are the Arizona Partners in Flight Conservation Recommendations.

Habitat Loss

Associated Species: Other species that may use similar habitat components or respond positively to management for the Juniper Titmouse are: Ash-throated Flycatcher, Gray Vireo, Pinyon Jay, Western Scrub Jay, Black-throated Gray Warbler, Western Bluebird, Scott’s Oriole.

Distribution: Resident from southeastern Oregon, northeastern Nevada, southeastern Idaho, southern Wyoming, central Colorado, and extreme Oklahoma south (east of the Sierra Nevada) to southeastern California, central and southeastern Arizona, extreme northeastern Sonora, southern New Mexico, and extreme western Texas (AOU 1998). In Arizona, it is a fairly common to common resident in the northeastern, northern, central, and locally southeastern portions of the state. The range extends west to Mount Trumbull and the Cerbat, Hualapi, Bradshaw, Superstition, Galiuro, and Chiricahua Mountains (Monson and Phillips 1981).

Ecology: An obligate inhabitant of pinyon-juniper woodlands (Andrews and Righter 1992, Behle 1985, Phillips and others 1964, Small 1994). Occurs as singles or pairs and does not typically form conspecific flocks although it does occur in mixed-species flocks (Phillips and others 1964). Balda (1987) states that Juniper Titmouse are "major pine seed predators" that may consume "large numbers of seeds." Bradfield (1974) observed it feeding on juniper seeds in the fall. It is likely largely insectivorous during the warmer half of the year. An obligate secondary cavity nester. Of 13 active nests found as part of the Arizona Breeding Bird Atlas, nine (79 %) were in junipers (T. Corman, AGFD, pers. observ.). Nesting dates ranged from 15 May to 30 June. Nest cavity heights were from 1.12 m to 4.40 m. The diameter (dbh) of the nest trees varied from 14-48 cm (5.5-1.5 in). It is probably not subject to brood parasitism by Brown-headed Cowbirds. Breeding densities from three study sites over two years in central Arizona ranged from 28.7 to 52.0 pairs per 40 ha (100 ac) which made up 23.5% to 43.6% of the total breeding bird density (Masters 1979). In a similarly study using identical methods in northeastern Arizona (LaRue 1994) reported 7.6 to 11.5 pairs per 40 hectares comprising 7.4% to 17.7% of the total breeding bird density.

Habitat Requirements: The Juniper Titmouse is highly restricted to pinyon-juniper woodlands (Andrews and Righter 1992, Balda and Masters 1980, Behle 1985, Bradfield 1974, Phillips and others 1964, Small 1994). It occasionally wanders into other habitats (usually riparian) within its range that are adjacent to or near pinyon-juniper woodlands during the nonbreeding season (Andrews and Righter 1992, Bradfield 1974, Brown and others 1984, Phillips and others 1964, Small 1994, Sogge and others 1998). The Juniper Titmouse is virtually unknown as a transient outside of the range cited above (Rea 1983, Rosenberg and others 1991, Witzeman and others 1997). Tree density in two Pinyon-juniper breeding bird investigations that examined stands supporting breeding titmice (LaRue 1994, Masters 1980) ranged from 155 to 380 trees per hectare. Canopy cover of one study (LaRue 1994) varied from 11% to 26%. Combined, these studies indicate that the proportion of the breeding bird density the titmouse contributes to tends to drop with increasing tree density, increasing total bird density, increasing proportion of junipers, and increasing canopy cover.

Habitat and/or Population Objectives:

Formerly known as Plain Titmouse (Parus inornatus). However it has recently been split (AOU 1997) into two species, with the interior forms being called the Juniper Titmouse and those populations west of the Sierra Nevada called the Oak Titmouse (B. inornatus). Most available information on the "Plain Titmouse" (e.g. Ehrlich and others 1988) is based on studies of the Oak Titmouse in California. Therefore, little is known specifically for the Juniper Titmouse. Because it is clearly associated with mature pinyon-juniper woodlands, management activities that favor these stands will benefit this species. Investigations to determine specific habitat requirements and basic natural history are needed.

Juniper Titmouse management issues are listed in italics. Below each issue are the Arizona Partners in Flight Conservation Recommendations.