Empidonax hammondii is most commonly found in the western parts of the United States and Canada. Empidonax hammondii or Hammond's flycatcher can be spotted from east-central Alaska all the way down to east-central California and north-central New Mexico. These birds live in mountain forests and prefer to live in closed canopy forests, where barely any light peaks through (Gillson 1997; The National Conservancy 1999).

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Breeding

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Breeding

Global Range: (20,000-2,500,000 square km (about 8000-1,000,000 square miles)) BREEDING: east-central Alaska, southern Yukon, northeastern British Columbia, southwestern Alberta, western and south-central Montana, northwestern Wyoming, south through northwestern U.S. (Washington, Oregon, Idaho) to east-central California, Utah, northeastern Arizona, western Colorado, and north-central New Mexico (AOU 1998, Sedgwick 1994). Centers of breeding abundance, based on BBS data, are in the Pacific Northwest from northern California to British Columbia, and in the northern Rockies (Sauer et al. 1997). NON-BREEDING: southeastern Arizona, south through highlands of Mexico, Guatemala and El Salvador to Honduras and probably Nicaragua (AOU 1998).

E. hammondii on average range in height from 12.7-14.0 cm long. The male length is 14.0-14.6 cm with a wing size of 6.6-7.1 cm, a tail size of 5.8-6.4 cm, and a bill size of 1.3-1.5 cm. The female length is 13.3 cm with a wing size of 6.2-7.0 cm and a tail size of 5.5-6.1 cm. As youths, these birds are brownish colored with yellowish-brown wing bars. As adults, E. hammondii have grayish upper parts, whitish or yellowish wing bars, grayish throat, and a dark colored breast (Bailey 1920; Reader's Digest 1990).

Length: 14 cm

Weight: 10 grams

See Whitney and Kaufmann (1985) for details on identification.

• Terrestrial

E. hammondii lives mostly in mature mountain forests. Large dense-canopy and open-understory forests are vital for this species to thrive (The Nature Conservancy 1999; Reader's Digest 1990).

Terrestrial Biomes: forest ; mountains

Comments: BREEDING: Associated with cool forest and woodland, primarily in dense fir; found in western hemlock/western redcedar/grand fir forests (Tsuga heterophylla/ Thuja plicata/ Abies grandis), red fir (Abies magnifica), mixed conifer, Douglas-fir (Pseudotsuga menziesii), ponderosa pine (Pinus ponderosa), lodgepole pine (Pinus contorta), spruce-fir (Picea engelmannii/ Abies lasiocarpa) and aspen (Populus tremuloides). Several studies across the species range show a strong association with old-growth or mature stands, and lower abundances in young, pole/sawtimber, or open-canopied stands (Sakai 1987 cited in Sedgwick 1994, Raphael et al 1988, Hejl and Woods 1991, Manual 1991, Sakai and Noon 1991, Hansen et al. 1995, Anthony et al. 1996, Hutto and Young 1999).

In Pacific Northwest Cascade forests, optimum habitat is dry or mesic old-growth or mature Douglas-fir (Manuwal 1991, Hansen et al. 1995); becomes rare where the density of trees with a greater than 10 centimeter dbh is either less than 60 trees per hectare or more than 600 trees per hectare (Hansen et al. 1995). Most abundant in mature (95-190 years) or mesic to dry old-growth (200-700 years; Manuwal 1991). In one study where the overstory decreased with stand age, however, the species was found to be more abundant in young stands than in mature or old-growth (Carey et al. 1991). In the Rocky Mountains, common in mesic hemlock/cedar/grand fir forests, mixed conifer, spruce-fir and aspen (Hejl et al. 1995). On Northern Rockies regional surveys, was most often observed in relatively uncut conifer forests and in riparian areas closely associated with conifer forests; showed a preference for western red cedar/Grand fir, Douglas-fir, ponderosa pine, and mixed conifer, and was detected more often in old-growth than mature stands (Hutto and Young 1999). Often in mixed broad-leaved and coniferous stands in western Montana (Davis 1954, Manuwal 1970); in Douglas-fir/ponderosa pine forests, the species is significantly more abundant in old growth (more than 200 years) than rotation-aged stands (80-120 years; Hejl and Woods 1991). In Oregon Douglas-fir forests, associated only on upslope sites compared to riparian sites in one study (McGarigal and McComb 1992), but on another study was found in sites along small streams within coniferous forest and was most abundant in old-growth or mature stands compared to young stands (Anthony et al. 1996). In California Sierra Nevada red-fir forests, abundance increased with increasing canopy closure; greatest abundances were detected in dense stands of more than 60 percent canopy closure (Hejl and Verner 1988). In northwestern California Douglas-fir, was twice as abundant in mature forest (trees greater than 60 centimeters dbh and greater than 40 meters tall; more than 100 years) than in pole/sawtimber stands (trees 6-40 meters tall with crowns less than or equal to 8 meters in diameter; Raphael et al. 1988).

Often nests in Douglas-fir or ponderosa pine (Bowles and Decker 1927, Sakai and Noon 1991), also western larch (Larix occidentalis), tanoak (Lithocarpus densiflorus), white fir (Abies concolor), grand fir, aspen, birch (BETULA spp.), and maple (ACER spp.; Sedgwick 1994). Selects nest sites in forests with few, small understory trees, clumps of tall, dense conifers, and overstory trees with well-developed canopies (Manuwal 1970, Mannan 1984). Places nests in large (more than 27 centimeter dbh), tall live trees in Oregon mixed-conifer forests (Mannan 1984). In Douglas-fir/tanoak forest in northwestern California, nests in mature and old-growth forest, with nest concealed by foliage cover on a horizontal branch or fork of a live, tall, large-diameter tree (Sakai and Noon 1991). Nests from 2 to 20 meters up (see Bowles and Decker 1927, Davis 1954, Mannan 1984, Sakai and Noon 1991, Baicich and Harrison 1997).

NON-BREEDING: In migration and winter, passes through deserts and occurs in scrub, pine and pine-oak association (AOU 1983). In winter in Mexico and Central America, found in highland forests, humid to semi-arid pine, pine-oak, and evergreen forest and edge; mid- to upper canopy (Howell and Webb 1995). In western Mexico, apparently a pine-oak-fir forest specialist (Hutto 1992).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.

Northbound migrants arrive in U.S. March-May (Terres 1980). Migrate earlier in spring and later in fall than dusky flycatcher (Empidonax oberholseri; NGS 1999). In spring, migration lasts from mid-March to early June; males migrate ahead of females and first-year juveniles and pass chiefly through coastal states; second wave largely of females and fewer males passes through interior; timing and location of routes may be related to climatic conditions (Johnson 1965). Fall migrants pass through coastal states to Arizona from late August through late October; interior migration is shorter duration and peaks in mid-September; all then funnel through southeastern Arizona and southwestern Mexico (Johnson 1970).

E. hammondii mainly eats insects such as ants and flying insects. They prefer to search for flying insects in the center parts of tall conifers and aspens. The types of flying insects they eat are beetles, moths, and flies. Mostly, E. hammondii sit and wait for an insect to be in sight and then quickly move in for the kill, their beaks opening and quickly snapping shut. They then return to where they sat to wait for the next insect (Bailey 1920; Gillson 1997; Reader's Digest 1990; USGS 1998).

Comments: Flies out from a perch, usually high in tree, to catch insects in the air. Will hover-glean in early stages of breeding season, later switching to flycatching and gleaning from woody substrates, probably related to prey availability (Sakai and Noon 1990). Eats caterpillars, butterflies, moths, beetles, flies, bees and wasps (Terres 1980, Sedgwick 1994). In a Colorado study, Coleoptera and Lepidoptera greatest proportion of diet by dry weight, followed by Diptera and Hymenoptera (Beaver and Baldwin 1975).

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: Number of occurrences not quantified but likely many.

10,000 to >1,000,000 individuals

Comments: Abundance estimates not known. Relative abundance according to North American Breeding Bird Survey (BBS), 1966-1996, highest in British Columbia (6.3 birds per survey route). In Washington and Montana, relative abundance also over 4.0 birds per route. Survey-wide, relative abundance was 3.66 for same period (Sauer et al. 1997).

Density estimates have been reported in a variety of habitats. In Northwestern California Douglas-fir (Pseudotsuga menziesii) forest, 40 birds per 100 hectares in old-growth, 20 birds per 100 hectares in mature stands (Sakai 1987, cited in Sedgwick 1994); 14.1 birds per 100 hectares in mature forest, 6.9 birds per 100 hectares in sawtimber stands (Raphael et al. 1988). In Oregon coast range Douglas-fir forest, 69.9 birds per 100 hectares in young (40-72 years) stands, 50.6 birds per 100 hectares in mature (80-120 years), and 17.4 birds per 100 hectares in old-growth (200-525 years; Carey et al. 1991). In western Montana Douglas-fir/Ponderosa pine (Pinus ponderosa), 17.0-17.3 territorial males per 100 hectares (Manuwal 1970 cited in Sedgwick 1994). In a California mature mixed-coniferous forest and montane chaparral, 16.6-41.4 territories per 100 hectares recorded (North 1989, Purcell 1990, Nelson et al. 1991, Purcell et al. 1992a). In California old-growth mixed coniferous-red fir (Abies magnifica) transition forest, 22.5-59 territories per 100 hectares recorded (Breese 1989, Kee 1990, Davis et al. 1991, Purcell et al. 1992b). In Colorado, 14-47 birds per 100 hectares in aspen, 14-28 birds per 100 hectares in aspen-conifer habitat (Beaver and Baldwin 1975).

Relative abundances range from an average 0.65 (Colorado) to 7.62 (Cascade Mountains) birds per 25-mile survey route (Sauer et al. 1997). Fall mortality of immatures apparently high (Johnson 1970). Shows low genetic variation as well as extreme morphological uniformity across a range spanning 30 degrees of latitude, possibly due to past population bottlenecks (Johnson 1966, Johnson and Marten 1991).

Breeding season occurs between early June and late July. E. hammondii females have 3-4 whitish or yellowish eggs and incubate the eggs for 12-15 days. They nest in Douglas fir, ponderosa pine, western larch, tanoak, white fir, grand fir, aspen, birch, and maple. They prefer forest sites with clumps of tall conifers with well-developed canopies. The nest is a cup of bark, plant fibers, pine needles, and twigs that is built 6-60 ft. above the ground. The young leave the nest 17-18 days after hatching (Gillson 1997; The Nature Conservancy 1999; Reader's Digest 1990).

Breeding season from early June to late July (Baicich and Harrison 1997). Clutch size is two to four. Incubation, by female, lasts 15 days. Young are tended by both adults, leave nest 17-18 days after hatching. Single-brooded; will replace lost clutches.

Cool, shady forests for nesting, roosting, and foraging are essential for keeping E. hammondii populations from extinction. This species is still commonly found in the Pacific Northwest. Timber harvest and fires can sometimes actually benefit Hammond's flycatcher if the forest understory is opened up while the canopy remains closed. The open understory spaces facilitate E. hammondii's flight. More research (e.g. on the effects of timber harvest) is needed about threats to the species (The Nature Conservancy 1999).

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5B - Secure

United States

Rounded National Status Rank: N5B - Secure

Rounded Global Status Rank: G5 - Secure

Reasons: Common in right habitat. Increasing or stable.

Global Short Term Trend: Relatively stable (=10% change)

Comments: As a result of the past century of timber harvest, the species may have declined overall in northwestern Douglas-fir (Pseudotsuga menziesii) and southwestern ponderosa pine (Pinus ponderosa) forests (Raphael et al. 1988, Hejl 1994). Has increased in Alaska, however, due to a northward range expansion (DeSante and George 1994). Current populations appear to be stable to increasing overall, with some local declines. Trend analysis from North American Breeding Bird Survey (BBS) data shows positive but non-significant long-term population increase survey-wide, 1966-1996 (1.2 percent annual change, P = 0.24, n = 269 survey routes), and a significant increase from 1980 to 1996 (2.9 percent annual change, P = 0.01, n = 257). From 1966 to 1996, a significant increase is evident in Washington, (6.7 percent annual change, P = 0.01, n = 42) and a significant decline in the Fraser plateau of central British Columbia (-6.4 percent annual change, P = 0.00, n = 17 survey routes). From 1980 to 1996, trend estimates show significant increases in Washington (6.2 percent annual change, P = 0.09, n = 38) and province-wide in British Columbia (4.0 percent annual change, P = 0.02, n = 62). Trend estimates for other states are not statistically significant. Mapped 30-year trends (1966-1996) show declines in central British Columbia, western Oregon, northern California, and the Northern Rockies of Montana, Idaho and Wyoming, and increases in western Washington, coastal and Rocky Mountain British Columbia, and the southern Rockies.

Degree of Threat: C : Not very threatened throughout its range, communities often provide natural resources that when exploited alter the composition and structure over the short-term, or communities are self-protecting because they are unsuitable for other uses

Comments: Threats to the species are largely unstudied. In the Great Basin, the species scored high for vulnerability to extirpation due to its rarity in the region, habitat specialization, potential vulnerability to cowbird brood parasitism, and its migratory status (Reed 1995). HABITAT LOSS: Occurs in commercially valuable coniferous forests, particularly mature and old-growth stands. Overstory removal eliminates habitat (Hagar 1960, Hansen et al. 1995) and the species would be likely to decline with continued widespread harvest by clearcutting or other overstory removal methods (Raphael et al. 1988, Saab and Rich 1997). Loss, reduction, or opening up of old-growth and mature forests will probably result in a decline in the breeding density (Sakai and Noon 1991, Hutto and Young 1999). May be sensitive to edge, forest fragmentation, and shrinking patch sizes (Aney 1984, Rosenberg and Raphael 1986, Hejl and Paige 1993). PARASITISM: Has been recorded as a brown-headed cowbird (Molothrus ater) host, but no information on parasitism rates or behavioral response (Sedgwick 1994). PREDATION: Sixty percent of nests depredated by Steller's jay (Cyanocitta stelleri) in California study (Sakai 1988, cited in Sedgwick 1994). Also respond to chipmunks (Eutamias spp.). Red squirrel (Tamiasciurus hudsonicus) and chickarees (T. DOUGLASI) are other potential nest predators. FIRE: Stand-replacing fires, crown fires and scorching destroy habitat, but persists in underburned sites (Johnson and Wauer 1994). PESTICIDES: No quantitative information available, but application of forest insecticides that eliminate aerial insects would destroy the food base.

Restoration Potential: Still relatively common and widespread, but strongly tied to the persistence of older coniferous forests. The species would be best sustained by maintaining large forest blocks with well-developed canopies and open understories. Will likely increase as regenerating forests mature, if stands are allowed to develop shady canopies and support an adequate prey base.

Preserve Selection and Design Considerations: Larger dense-canopy and open-understory forest stands are essential habitat. May be area sensitive. In western Montana, Hammond's and Dusky flycatchers (Empidonax oberholseri) as a group showed a preference for old-growth ponderosa pine (Pinus ponderosa) stands and were sensitive to fragmentation and stand area. Minimum suggested stand size is 2 hectares which is several times larger than territories (Aney 1984). Others suggest intact stands greater than 10-15 hectares or preferably larger are needed to sustain the species (Sakai 1987, cited in Sedgwick 1994; Sakai and Noon 1991). In northern Idaho cedar/hemlock forests, avoided fragmented stands, but occurred in continuous old-growth and select-cut stands (Hejl and Paige 1993). In fragmented Douglas-fir (Pseudotsuga menziesii) forests of northwestern California, avoided clearcut edges but showed a positive correlation with the amount of edge in a 1000-hectare block; however, increased edge was also correlated with a greater amount of old-growth in the block (Rosenberg and Raphael 1986). Its habit of placing nests in dense foliage (Sakai and Noon 1991) and preference for cooler, shady forests may also indicate a need for forest interiors and a potentially negative effect of edge (USDA Forest Service 1994).

Management Requirements: Associated with cool, shady forests for nesting, roosting, and foraging. It appears that a shady well-developed canopy and open spaces in the understory to facilitate aerial foraging are important, and the presence of aerial insects is essential (Mannan 1984, USDA Forest Service 1994).

TIMBER HARVEST: Logging of old-growth or mature stands is detrimental, but canopy volume or closure and an open understory appear to be the significant variables. Creating clearings with remnant, scattered large trees is not beneficial (Sakai and Noon 1991). Abundances may increase in commercially thinned or selectively-cut forests that open up space in the understory for foraging (Hejl and Paige 1993, Hagar et al. 1996). Overall, the species should benefit by maintaining closed canopy stands with open understories.

FIRE: May benefit from burns that open up the understory for foraging flight paths (Johnson and Wauer 1994).

Management Research Needs: Further research is needed (on both breeding and wintering grounds) on habitat requirements, particularly vegetation parameters relevant to forest stand management, and on landscape relationships, including area sensitivity, effects of fragmentation, different types of edge. Threats to the species have been little studied. More information needed on effects of timber harvest (particularly at landscape and regional scales, as well as stand scale), response to changes in fire regimes, effects of forest insect pest control methods, rates of brood parasitism.

Biological Research Needs: Has a broad distribution and is relatively common on breeding grounds but is still poorly known (Sedgwick 1994). More information is needed on basic natural history, including nesting biology and success, site fidelity, causes of mortality, and interactions with other species (predation, competition, brood parasitism). Further study is needed of winter ecology and habitat use during winter and migration. Research on demography needed, including productivity and survival.

Unknown

Empidonax hammondii are a forest insectivore and may be crucial in controlling forest insect populations (The Nature Conservancy 1999).

Stewardship Overview: Found in the shady and cool coniferous or mixed coniferous-deciduous forests of the West. Though common, it is easily confused with other Empidonax flycatchers and the details of its natural history and ecology are somewhat poorly known. Populations appear to be stable to increasing in recent years, though the species may have lost ground in the past century with extensive timber harvest throughout its range. Deforestation is the principal known threat to the species and it is probably sensitive to forest fragmentation. Little is known about the winter habits or threats on its wintering grounds.

Species Impact: A forest insectivore, may play an important role in controlling forest insect populations.

Comments: Morphologically uniform and with low genetic variability across entire range (Johnson and Marten 1991).