Pipilo chlorurus - (Audubon, 1839)
Green-tailed Towhee
Other English Common Names: green-tailed towhee
Taxonomic Status: Accepted
Related ITIS Name(s): Pipilo chlorurus (Audubon, 1839) (TSN 179310)
French Common Names: Tohi à queue verte
Spanish Common Names: Toquí Cola Verde
Unique Identifier: ELEMENT_GLOBAL.2.104040
Element Code: ABPBX74010
Informal Taxonomy: Animals, Vertebrates - Birds - Perching Birds
 
Kingdom Phylum Class Order Family Genus
Animalia Craniata Aves Passeriformes Passerellidae Pipilo
Genus Size: C - Small genus (6-20 species)
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Concept Reference
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Concept Reference: American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.
Concept Reference Code: B98AOU01NAUS
Name Used in Concept Reference: Pipilo chlorurus
Taxonomic Comments: Often has been treated in the monotypic genus Chilorur (or Oberholseria); the latter name is a junior synonym of the former (Banks and Browning 1995). See Banks and Browning (1995) for a discussion of nomenclatural issues involving Pipilo.
Conservation Status
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NatureServe Status

Global Status: G5
Global Status Last Reviewed: 01Dec1998
Global Status Last Changed: 04Dec1996
Rounded Global Status: G5 - Secure
Nation: United States
National Status: N5B,N5N (05Jan1997)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Arizona (S3B,S4N), California (SNRB), Colorado (S5), Idaho (S4B), Montana (S3B), Navajo Nation (S4B), Nebraska (SNRN), Nevada (S5B), New Mexico (S3B,S4N), Oklahoma (S1N), Oregon (S3S4), Texas (S4B), Utah (S4B), Washington (S2B), Wyoming (S5B,S5N)

Other Statuses

IUCN Red List Category: LC - Least concern

NatureServe Global Conservation Status Factors

Range Extent Comments: BREEDING: southwestern and central Oregon, southeastern Washington, southern Idaho, southwestern Montana, Wyoming, south through interior mountains to southern California, southern Nevada, central Arizona, southern New Mexico (AOU 1983). Breeding documented from Sierra San Pedro Martir, Baja California (Erickson and Wurster 1998). NON-BREEDING: southern California, southern Arizona, western and southern Texas, south to southern Baja California and central Mexico (Jalisco, Guanajuato, Queretaro, Morelos, Hidalgo, San Luis Potosi, and Tamaulipas). Migrants range east to western Kansas, western Oklahoma, and west-central Texas (AOU 1983).

Overall Threat Impact Comments: HABITAT LOSS, FRAGMENTATION, DEGRADATION: In sagebrush shrub-steppe habitats, land conversion to cultivated croplands, sagebrush control, seeding with non-native grasses for livestock, wide-scale invasion of exotic annuals (e.g. cheatgrass), and high-intensity grazing have degraded and fragmented the sagebrush community mosaic and reduced habitat for sagebrush birds (Paige and Ritter 1998). Sagebrush shrub-steppe is in generally poor condition, and is under high threat of habitat loss, conversion and fragmentation (Saab and Rich 1997). Towhees show a strong preference for sagebrush habitats in many areas, and widespread alteration of sagebrush probably impacts the species, possibly altering the species' distribution (Dobbs et al. 1988). FIRE SUPPRESSION: Broad-scale fire suppression in this century and the reduction of post-fire successional habitats may be degrading towhee breeding habitat, particularly in montane coniferous forests, due to reduction in shrub layers and an increase in canopy shading (Dobbs et al. 1998, Bock et al. 1978, Hejl 1994). Mountain shrublands, prairie brush fields, and juniper woodlands are under moderate threats in many areas from high-intensity grazing, fire suppression, invasion of exotic species, and conversion to annual grasslands (Saab and Rich 1997). These activities would likely reduce towhee habitat, however there is no quantitative information on associated impacts on towhees. PREDATION: Mean predation rates for shrub nesting species in generalized shrub/grassland habitats 40% to 44% (Martin 1993a, Martin 1995). On Mogollon Rim, Arizona, observed > 75% nests failure due to nest predators (Dobbs et al. 1998, Martin and Li 1992). Reported predators include accipiters, peregrine falcon (FALCO PEREGRINUS), American kestrel (FALCO SPARVERIUS), long-eared owl (ASIO OTUS), red-tailed hawk (BUTEO JAMAICENSIS), Steller's jay (CYANOCITTA STELLERI), black-billed magpie (PICA PICA), red squirrel (TAMIASCIURUS HUDSONICUS), least chipmunk (EUTAMIAS MINIMUS), long-tailed weasel (MUSTELA FRENATA, striped skunk (MEPHITIS MEPHITIS), spotted skunk (SPILOGALE PUTORIUS), and gopher snake (PITUOPHIS MELANOLEUCUS) (Dobbs et al. 1998). COMPETITION: One record of aggression with fox sparrow (PASSERELLA ILIACA) over song perches, ending in mutual tolerance (Clark 1932). BROOD PARASITISM: Recorded as an occasional host of brown-headed cowbird (MOLOTHRUS ATER) (Friedmann et al. 1977, Ehrlich et al. 1988, Dobbs et al. 1998). Mean cowbird parasitism rates for shrub-nesting species in generalized shrub/grassland habitats 15% (Martin 1993a, 1993b), but extent of parasitism unknown.

Short-term Trend Comments: North American Breeding Bird Survey (BBS) data show a stable to slightly declining population trend for the Western BBS region 1966-1996 (n = 227 survey routes). Significant and strong declines in Oregon and the Wyoming Basin, 1966-1996 (Sauer et al. 1997). A significant increase indicated in Utah and the pinyon-juniper woodland physiographic region for 1966-1996 and 1980-1996. Mapped BBS trends, 1966-1996, reveal a pattern of declines in eastern and western portions of the range, through the Rocky Mountain and Cascade/Sierra Nevada corridors; population increase in the Great Basin (the geographical core of the range) (Sauer et al. 1997). Christmas Bird Count (CBC) data show a stable trend for 1959 to 1988 survey-wide (n = 197 survey circles) with towhees observed on > 20 circles in Arizona, California, New Mexico, and Texas; relative abundances low, highest in Arizona and west Texas borderlands (Sauer et al. 1996). Interpretations of BBS and CBC data should be made with caution due to low sample sizes in many states and regions. In pinyon-juniper woodlands, large-scale conversion of pinyon-juniper to annual grasslands for livestock, especially since 1950, has likely increased habitat for towhees, which favor sagebrush openings, early successional shrubfields, and areas of high shrub species richness (see Sedgwick 1987). In other high-elevation forest types, timber harvest practices that result in extensive areas of successional shrub fields on harvest units have likely increased habitat (Dobbs et al. 1998, Franzreb and Ohmart 1978). For example, change in the distribution of seral stages of Douglas fir forests in northern California over the past century have favored ground- and shrub-foragers, including towhees (Raphael et al. 1988, Hejl 1994). Weather patterns can affect year to year differences in towhee abundance and heavy snowfall apparently depressed towhee numbers and distribution in Sierra Nevada fir forests (Hejl et al. 1988).

Other NatureServe Conservation Status Information

Distribution
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Global Range: BREEDING: southwestern and central Oregon, southeastern Washington, southern Idaho, southwestern Montana, Wyoming, south through interior mountains to southern California, southern Nevada, central Arizona, southern New Mexico (AOU 1983). Breeding documented from Sierra San Pedro Martir, Baja California (Erickson and Wurster 1998). NON-BREEDING: southern California, southern Arizona, western and southern Texas, south to southern Baja California and central Mexico (Jalisco, Guanajuato, Queretaro, Morelos, Hidalgo, San Luis Potosi, and Tamaulipas). Migrants range east to western Kansas, western Oklahoma, and west-central Texas (AOU 1983).

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
NOTE: The maps for birds represent the breeding status by state and province. In some jurisdictions, the subnational statuses for common species have not been assessed and the status is shown as not-assessed (SNR). In some jurisdictions, the subnational status refers to the status as a non-breeder; these errors will be corrected in future versions of these maps. A species is not shown in a jurisdiction if it is not known to breed in the jurisdiction or if it occurs only accidentally or casually in the jurisdiction. Thus, the species may occur in a jurisdiction as a seasonal non-breeding resident or as a migratory transient but this will not be indicated on these maps. See other maps on this web site that depict the Western Hemisphere ranges of these species at all seasons of the year.
Endemism: occurs (regularly, as a native taxon) in multiple nations, but breeds in a single nation

U.S. & Canada State/Province Distribution
United States AZ, CA, CO, ID, MT, NE, NM, NN, NV, OK, OR, TX, UT, WA, WY

Range Map
Note: Range depicted for New World only. The scale of the maps may cause narrow coastal ranges or ranges on small islands not to appear. Not all vagrant or small disjunct occurrences are depicted. For migratory birds, some individuals occur outside of the passage migrant range depicted. For information on how to obtain shapefiles of species ranges see our Species Mapping pages at www.natureserve.org/conservation-tools/data-maps-tools.

Range Map Compilers: NatureServe, 2002


U.S. Distribution by County Help
State County Name (FIPS Code)
MT Beaverhead (30001), Big Horn (30003), Blaine (30005), Broadwater (30007), Carbon (30009), Chouteau (30015), Custer (30017), Deer Lodge (30023), Fergus (30027), Gallatin (30031), Garfield (30033), Granite (30039), Jefferson (30043), Judith Basin (30045), Lewis and Clark (30049), Madison (30057), Meagher (30059), Musselshell (30065), Park (30067), Petroleum (30069), Phillips (30071), Powder River (30075), Silver Bow (30093), Stillwater (30095), Sweet Grass (30097), Valley (30105), Wheatland (30107), Yellowstone (30111)
WA Asotin (53003)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
10 Red Rock (10020001)+, Beaverhead (10020002)+, Ruby (10020003)+, Big Hole (10020004)+, Jefferson (10020005)+, Boulder (10020006)+, Madison (10020007)+, Gallatin (10020008)+, Upper Missouri (10030101)+, Upper Missouri-Dearborn (10030102)+, Smith (10030103)+, Judith (10040103)+, Fort Peck Reservoir (10040104)+, Upper Musselshell (10040201)+, Box Elder (10040204)+, Lower Musselshell (10040205)+, Peoples (10050009)+, Yellowstone Headwaters (10070001)+, Upper Yellowstone (10070002)+, Shields (10070003)+, Upper Yellowstone-Lake Basin (10070004)+, Stillwater (10070005)+, Clarks Fork Yellowstone (10070006)+, Big Horn Lake (10080010)+, Shoshone (10080014)+, Lower Bighorn (10080015)+, Little Bighorn (10080016)+, Lower Tongue (10090102)+, Rosebud (10100003)+
17 Upper Clark Fork (17010201)+, Flint-Rock (17010202)+, Upper Henrys (17040202)+*, Lower Grande Ronde (17060106)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: A bird (towhee).
Reproduction Comments: Clutch size two to four (usually four). Nestlings altricial and downy.
Ecology Comments: In Colorado, mean breeding density reported at 3.0 pairs per 40 ha in aspen/willow and spruce/aspen stands (Winternitz 1976).
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: Y
Mobility and Migration Comments: Migrates northward and to higher elevations late February-early May (Terres 1980), southward and to lower elevations September-October, with postfledging dispersal peaking in late August (Sierra Nevada). Observed as common in New Mexico throughout migration (Bailey 1928). Observed in desert washes (containing acacia, mesquite hackberry, creosote bush, willow and palo verde) during spring migration (Szaro and Jakle 1985). Observed in dense shrub habitats during spring on islands in Gulf of California, off southern Baja California (Emlen 1979). Juvenile birds may disperse to subalpine meadows, particularly in dry years where food is limited elsewhere (Morton 1991, Dobbs et al. 1998).
Palustrine Habitat(s): Riparian
Terrestrial Habitat(s): Shrubland/chaparral
Habitat Comments: BREEDING: Thickets, chaparral, shrublands, riparian scrub, and especially sagebrush (ARTEMISIA spp). Habitat varies with elevation. Primarily in mountains (AOU 1983, Dobbs et al. 1998). Found on mountain slopes, plateaus, and higher valleys of arid West, associated with dense shrubs 0.5 to 1.5 m in height; most commonly uses dry shrubby hillsides and post-disturbance shrubby second growth (Dobbs et al. 1998, Knopf et al. 1990). Occurs up to 2400 m in elevation in Great Basin; 3000 m in Arizona; between 2100 m and 3400 m in New Mexico (Bailey 1928, Ligon 1961, Rising 1996). Rarely found below 1200 m (Burleigh 1972). Apparently attracted to dwarf mistletoe as a nest, roost or foraging site in southwestern Ponderosa pine forests (Anonymous 1991). Nests on or near ground in shrubby habitat; nest is usually under cover of brush or plant tufts; built by the female.

Habitat is usually low shrubs, sometimes interspersed with trees; avoids typical forest, other than open pinyon-juniper woodlands (Dobbs et al. 1998). In pinyon-juniper, associated with sagebrush (ARTEMISIA spp) dominated openings with high shrub species richness (Sedgwick 1987); uses juniper for song perches (Maser and Gashwiler 1978). In shrub-steppe habitats prefers ecotones between sagebrush and other shrubby habitats, especially mountain mahogany (CERCOCARPUS spp); often select a central bush of another shrub species within sagebrush-dominated patches; high shrub patch vigor (percent live branches and standing herbaceous biomass) important to nesting microhabitat (Knopf et al. 1990). In northern Great Basin, uses tall sagebrush/bunchgrass, squaw/sagebrush/bunchgrass, mountain mahogany/bunchgrass, mountain mahogany/pinegrass and aspen/sagebrush/bunchgrass communities as primary breeding and foraging habitat (Maser et al. 1984). In Montana, found in sagebrush habitats and higher elevation shrubby second-growth (Hutto 1995). In Colorado, recorded in Gambel oak (QUERCUS GAMBELLI), aspen/willow and spruce/aspen habitats (Dobbs et al. 1998, Winternitz 1976). In Arizona, nests in dry, high-elevation sites dominated by shrubby New Mexico locust (ROBINA NEOMEXICANA) and small conifers under canopy of ponderosa pine (PINUS PONDEROSA) (Martin 1993b, Dobbs et al. 1998); also in shrubby understories of open riparian corridors and saltbush (ATRIPLEX) along field edges (Rosenberg et al. 1991). In Sierra Nevada, observed in high numbers in dense successional brushfield that developed 8 to 15 years after fire in a pine-fir forest (Bock et al. 1978). In Baja California, breeding birds observed in aspen and in meadow openings within mixed coniferous forest at 2700 m (Erickson and Wurster 1998).

NON-BREEDING: Primarily in lowland habitats (AOU 1983, Dobbs et al. 1998). In Mexico, found in dry desert habitat with acacia, mesquite, and creosote bush (R.L. Hutto reported in Dobbs et al. 1998). Possibly limited in habitat use by distribution of water. Unlike desert-adapted sparrows, towhees are not tolerant of saline water (Dobbs et al. 1998, Smith and Ohmart 1969).

Adult Food Habits: Frugivore, Herbivore, Invertivore
Immature Food Habits: Frugivore, Herbivore, Invertivore
Food Comments: Feeds on seeds, berries, and insects. Forages on the ground by scratching beneath brush.
Adult Phenology: Diurnal
Immature Phenology: Diurnal
Length: 18 centimeters
Weight: 29 grams
Economic Attributes Not yet assessed
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Management Summary
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Stewardship Overview: Relatively common in shrubland habitats throughout the West, but is poorly known. Broad-scale habitat alterations, such as sagebrush (ARTEMISIA spp) conversion and degradation and fire suppression, could be limiting habitat in some regions, and affecting the distribution pattern; however other anthropogenic changes, such as timber harvest and juniper control that promote brushy seral habitats, may be augmenting habitat for towhees. There is indication of long-term population declines in eastern and western portions of the range. Deserves greater attention to better understand its habitat relationships, habitat and population trends, and conservation needs.
Restoration Potential: Still widespread and attention to maintaining habitat (i.e., species-rich shrublands) should help sustain the species.
Management Requirements: Activities that promote species-rich shrub habitats (e.g. sagebrush, mountain mahogany, chaparral, mesquite) with high shrub vigor should benefit habitat. Sagebrush control with burning, chaining, or herbicides eliminates habitat, and management for natural sagebrush mosaics interspersed with other shrub species and shrub habitats should favor the species (Braun et al. 1976, Knopf et al. 1990, Paige and Ritter 1998). Towhees can benefit from burns, timber harvest, and other management activities where post-fire or post-harvest habitats develop into brushfields (see Bock and Lynch 1970, Bock et al. 1978, Franzreb and Ohmart 1978, Raphael et al. 1988, Sedgwick 1987).
Monitoring Requirements: Currently is not well-sampled by existing geographically broad monitoring programs and may require specialized monitoring effort (Saab and Rich 1997). Sampling design must take into consideration distribution of high-elevation shrublands favored by towhees. Should be adequately monitored by standard point-count, transect, plot, or spot-mapping methods.
Management Research Needs: Details of population status and trends, habitat trends, and demographics poorly known. No information on impacts of grazing; burning or chaining of juniper woodlands; sagebrush control programs; invasive species; or alteration of herbaceous vegetation composition. More research needed on association with post-fire habitats, ecology of shrub communities. Wintering habitat and ecology poorly known. No information on landscape-scale patterns of habitat use; effects of habitat fragmentation; habitat patch size and connectivity requirements. No information on direct or indirect effects of pesticides or other contaminants. Little information on tolerance to disturbance. No information on limits to survival.
Biological Research Needs: Further research needed on population demographics and regulation, predation, brood parasitism, diseases, inter-species competition, migration and wintering habitat use, and nutrition and energetics (see Dobbs et al. 1998).
Population/Occurrence Delineation
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Group Name: Passerines

Use Class: Breeding
Subtype(s): Foraging Area, Nest Site, Nesting Colony
Minimum Criteria for an Occurrence: Evidence of historical breeding, or current and likely recurring breeding, at a given location, minimally a reliable observation of one or more breeding pairs in appropriate habitat. Be cautious about creating EOs for observations that may represent single breeding events outside the normal breeding distribution.

Mapping Guidance: Breeding occurrences include nesting areas as well as foraging areas.

For swallows and other species that have separate nesting and foraging areas, separations are based on nest sites or nesting areas, not to locations of foraging individuals. For example, nesting areas separated by a gap larger than the separation distance are different occurrences, regardless of the foraging locations of individuals from those nesting areas. This separation procedure is appropriate because nesting areas are the critical aspect of swallow breeding occurrences, tend to be relatively stable or at least somwhat predictable in general location, and so are the basis for effective conservation; foraging areas are much more flexible and not necessarily static.

Separation Distance for Unsuitable Habitat: 5 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Significant dispersal and associated high potential for gene flow among populations of birds separated by tens of kilometers (e.g., Moore and Dolbeer 1989), and increasing evidence that individuals leave their usual home range to engage in extrapair copulations, as well as long foraging excursions of some species, make it difficult to circumscribe occurrences on the basis of meaningful population units without occurrences becoming too large. Hence, a moderate, standardized separation distance has been adopted for songbirds and flycatchers; it should yield occurrences that are not too spatially expansive while also accounting for the likelihood of gene flow among populations within a few kilometers of each other.

Be careful not to separate a population's nesting areas and foraging areas as different occurrences; include them in the same occurrence even if they are more than 5 km apart. Mean foraging radius (from nesting area) of Brown-headed Cowbird females was 4.0 kilometers in California, 1.2 kilometers in Illinois-Missouri (Thompson 1994). Yellow-headed Blackbirds, Brewer's Blackbirds, and probably Red-winged Blackbirds all forage up to 1.6 kilometers away from breeding colony (Willson 1966, Horn 1968). In one study, Brewer's Blackbirds were found as far as 10 kilometers from nesting area (Williams 1952), but this may be unusual.

For swallows and other parrerines with similar behavioral ecology, separation distance pertains to nest sites or nesting colonies, not to locations of foraging individuals. For example, nesting areas separated by a gap of more than 5 km are different occurrences, regardless of the foraging locations of individuals from those nesting areas. This separation procedure is appropriate because nesting areas are the critical aspect of swallow breeding occurrences, tend to be relatively stable or at least somwhat predictable in general location, and so are the basis for effective conservation; foraging areas are much more flexible and not necessarily static.

Be cautious about creating EOs for observations that may represent single breeding events outside the normal breeding distribution.

Unsuitable habitat: Habitat not normally used for breeding/feeding by a particular species. For example, unsuitable habitat for grassland and shrubland birds includes forest/woodland, urban/suburban, and aquatic habitats. Most habitats would be suitable for birds with versatile foraging habits (e.g., most corvids).

Date: 10Sep2004
Author: Hammerson, G.

Use Class: Migratory stopover
Subtype(s): Foraging Area, Roost Site
Minimum Criteria for an Occurrence: For most passerines: Evidence of recurring presence of migrating individuals (including historical) and potential recurring presence at a given location; minimally a reliable observation of 25 birds in appropriate habitat.

For swallows: Evidence of recurring presence of migrating flocks (including historical) and potential recurring presence at a given location; minimally a reliable observation of 100 birds in appropriate habitat (e.g., traditional roost sites).

Occurrences should be locations where the species is resident for some time during the appropriate season; it is preferable to have observations documenting presence over at least 7 days annually.

EOs should not be described for species that are nomadic during nonbreeding season: e.g., Lark Bunting.

Be cautious about creating EOs for observations that may represent single events.

Separation Distance for Unsuitable Habitat: 5 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Separation distance somewhat arbitrary but intended to define occurrences of managable size for conservation purposes. Occurrences defined primarily on the basis of areas supporting concentrations of birds, rather than on the basis of distinct populations.

For swallows and other species with similar behavioral ecology, the separation distance pertains to communal roost sites rather than to foraging areas; the former tend to be more stable and specific over time than the latter.

Date: 03Sep2004
Author: Hammerson, G., and S. Cannings

Use Class: Nonbreeding
Subtype(s): Foraging Area, Roost Site
Minimum Criteria for an Occurrence: Any area used traditionally in the nonbreeding season (used for populations that are not resident in a location year-round). Minimally, reliable observations of 10 or more individuals in appropriate habitat for 20 or more days at a time. For G1-G3 species, observations of fewer individuals could constitute an occurrence of conservation value. Sites used during migration should be documented under the 'migratory stopover' location use class.

Separation Distance for Unsuitable Habitat: 5 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Separation distance is necessarily arbitrary but attempts to balance the high mobility of birds with the need for occurrences of reasonable spatial scope. Note that a population's roost sites and foraging areas are parts of the same occurrence, even if they are more than 5 km apart.

For swallows and other species with similar behavioral ecology, the separation distance pertains to communal roost sites rather than to foraging areas; the former tend to be more stable and specific over time than the latter.

Date: 03Sep2004
Author: Hammerson, G.

Use Class: Nonmigratory
Minimum Criteria for an Occurrence: Occurrences are based on evidence of historical presence, or current and likely recurring presence, at a particular location. Such evidence minimally includes collection or reliable observation and documentation of one or more individuals in or near appropriate habitat.

These occurrence specifications are used for nonmigratory populations of passerine birds.

Separation Barriers: None.
Separation Distance for Unsuitable Habitat: 5 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Significant dispersal and associated high potential for gene flow among populations of birds separated by tens of kilometers (e.g., Moore and Dolbeer 1989), and increasing evidence that individuals leave their usual home range to engage in extrapair copulations, as well as long foraging excursions of some species, make it difficult to circumscribe occurrences on the basis of meaningful population units without occurrences becoming too large. Hence, a moderate, standardized separation distance has been adopted for songbirds and flycatchers; it should yield occurrences that are not too spatially expansive while also accounting for the likelihood of gene flow among populations within a few kilometers of each other.

Be careful not to separate a population's nesting areas and breeding-season foraging areas as different occurrences; include them in the same occurrence even if they are more than 5 km apart. Blue jays have small summer home ranges but fly up to 4 kilometers to harvest mast (Tarvin and Woolfenden 1999). Flocks of pinyon jays range over 21-29 square kilometers (Ligon 1971, Balda and Bateman 1971); nesting and foraging areas may be widely separated. Tricolored blackbirds forage in flocks that range widely to more than 15 kilometers from the nesting colony (Beedy and Hamilton 1999).

Unsuitable habitat: Habitat not normally used for breeding/feeding by a particular species. For example, unsuitable habitat for grassland and shrubland birds includes forest/woodland, urban/suburban, and aquatic habitats. Most habitats would be suitable for birds with versatile foraging habits (e.g., most corvids).

Date: 10Sep2004
Author: Hammerson, G.
Notes: These specs pertain to nonmigratory species.
Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 01Dec1998
NatureServe Conservation Status Factors Author: Paige, C.
Management Information Edition Date: 01Dec1998
Management Information Edition Author: PAIGE, C.; REVISIONS BY M. KOENEN, D. KWAN, AND D.W. MEHLMAN
Management Information Acknowledgments: Support for the preparation of this abstract was provided by the National Fish and Wildlife Foundation's Neotropical Migratory Bird Conservation Initiative, through challenge grant number 97-270 to The Nature Conservancy, Wings of the Americas program. Matching funds for this grant were donated by Canon U.S.A., Inc.
Element Ecology & Life History Edition Date: 29Mar1994
Element Ecology & Life History Author(s): Hammerson, G.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
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  • Altman, R. 2000. Conservation strategy for landbirds in the northern Rocky Mountains of Washington and Oregon. ver. 1.0. Prepared for Oregon-Washington Partners in Flight. 86+pages.

  • Altman, R. 2000. Conservation strategy for landbirds of the east-slope of the Cascade Mountains in Washington and Oregon. ver. 1.0. Prepared for Oregon-Washington Partners in Flight. 81+pages.

  • American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.

  • American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.

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  • Anonymous. 1991. Diversity and dwarf mistletoe. BioScience 41:755.

  • Bailey, F.M. 1928. Birds of New Mexico. New Mexico Department of Game and Fish.

  • Balda, R. P., and G. C. Bateman. 1971. Flocking and annual cycle of the piñon jay, Gymnorhinus cyanocephalus. Condor 73:287-302.

  • Banks, R. C., and M. R. Browning. 1995. Comments on the status of revived old names for some North American birds. Auk 112:633-648.

  • BirdLife International. 2004b. Threatened birds of the world 2004. CD ROM. BirdLife International, Cambridge, UK.

  • Bock, C.E., M. Raphael, and J.H. Bock. 1978. Changing avian community structure during early post-fire succession in the Sierra Nevada. Wilson Bulletin 90:119-123.

  • Bock, C.E., and J.F. Lynch. 1970. Breeding bird populations of burned and unburned conifer forest in the Sierra Nevada. Condor 72:182-189.

  • Braun, C.E., M.F. Baker, R.L. Eng, J.S. Gashwiler, and M.H. Schroeder. 1976. Conservation committee report on effects of alteration of sagebrush communities on the associated avifauna. Wilson Bulletin 88:165-171.

  • Burleigh, T. D. 1972. Birds of Idaho. Caldwell, Idaho: Caxton Printers, Ltd.

  • Clark, H.W. 1932. Breeding range of the Yolla Bolly fox sparrow. Condor 34:113-117.

  • Dobbs, R.C, P.R. Martin, and T.E. Martin. 1998. Green-tailed Towhee (PIPILO CHLORURUS). In A. Poole and F. Gill, editors, The Birds of North America, No. 368. The Birds of North America, Inc., Philadelphia, PA. 24 pp.

  • Dobbs, R.C., P.R. Martin, and T.E. Martin. 1998. Green-tailed towhee (Pipilo chlorurus) No. 368 IN A. Poole and F. Gill, editors. The birds of North America. The Birds of North America, Inc., Philadelphia, PA. 24p.

  • Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1988. The birder's handbook: a field guide to the natural history of North American birds. Simon and Shuster, Inc., New York. xxx + 785 pp.

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