Rhynchophanes mccownii - (Lawrence, 1851)
McCown's Longspur
Other English Common Names: McCown's longspur
Synonym(s): Calcarius mccownii (Lawrence, 1851)
Taxonomic Status: Accepted
Related ITIS Name(s): Calcarius mccownii (Lawrence, 1851) (TSN 179525)
French Common Names: bruant de McCown, plectrophane de McCown
Spanish Common Names: Escribano de Mccown
Unique Identifier: ELEMENT_GLOBAL.2.101543
Element Code: ABPBXA6010
Informal Taxonomy: Animals, Vertebrates - Birds - Perching Birds
 
Kingdom Phylum Class Order Family Genus
Animalia Craniata Aves Passeriformes Calcariidae Rhynchophanes
Genus Size: A - Monotypic genus
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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: Calcarius mccownii
Taxonomic Comments: Previously in the genus Calcarius, transferred to Rhynchophanes by AOU (2010).
Conservation Status
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NatureServe Status

Global Status: G4
Global Status Last Reviewed: 09Apr2016
Global Status Last Changed: 03Sep2003
Ranking Methodology Used: Ranked by inspection
Rounded Global Status: G4 - Apparently Secure
Reasons: Still apparently secure overall, but dramatic declines have occurred in the northern part of the range.
Nation: United States
National Status: N4B,N4N (03Sep2003)
Nation: Canada
National Status: N3N4B,N3N4M (13Dec2017)

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 (S2N), California (SNRN), Colorado (S2B), Kansas (S3N), Minnesota (SXB,SNRM), Montana (S3B), Nebraska (S3), New Mexico (S3N), North Dakota (S2), Oklahoma (S2N), South Dakota (SUB), Texas (S4), Wyoming (S2)
Canada Alberta (S3S4B), Saskatchewan (S3B)

Other Statuses

Canadian Species at Risk Act (SARA) Schedule 1/Annexe 1 Status: SC (13Dec2007)
Committee on the Status of Endangered Wildlife in Canada (COSEWIC): Threatened (29Apr2016)
Comments on COSEWIC: Reason for designation: This species has experienced a severe population decline since the late 1960s. This trend appears, however, to have slowed in the past decade. The species is threatened by continuing habitat loss and degradation. It may also risk exposure to pesticides associated with increased breeding in cultivated fields.

Status history: Designated Special Concern in April 2006. Status re-examined and designated Threatened April 2016.

IUCN Red List Category: LC - Least concern

NatureServe Global Conservation Status Factors

Range Extent: >2,500,000 square km (greater than 1,000,000 square miles)
Range Extent Comments: BREEDING: southeastern Alberta, southern Saskatchewan, northern North Dakota and (previously) southwestern Minnesota, south through Montana to southeastern Wyoming, northeastern Colorado, Oklahoma, northwestern Nebraska, and Manitoba (With 1994a, AOU 1998). NON-BREEDING: primarily from western Oklahoma, western Kansas, southeastern Arizona, and central New Mexico south through Sonora and Chihuahua to northern Durango (With 1994a, AOU 1998). Rarely in Idaho, Utah, Nevada, and ne and coastal California (With 1994a).

Number of Occurrences: 81 to >300
Number of Occurrences Comments: No exact figures.

Population Size: 10,000 to >1,000,000 individuals
Population Size Comments: Peak abundance in western Montana, southwestern Saskatchewan, and southeastern Wyoming. Locally abundant in shortgrass prairie and overgrazed pastures. In n.-central Colorado estimated 46.9 pairs per 100 hectares on a heavily grazed pasture in 1969. Another study estimated 81.5 individuals per 100 hectares in the same pasture in 1974. In a less preferred lightly grazed pasture found only 13.6 pairs per 100 hectares. In Saskatchewan estimated 79 individuals per 100 hectares. Breeding densities in Wyoming were higher with 76.6 pairs per 100 hectares (See With 1994a).

Overall Threat Impact Comments: HABITAT LOSS AND FRAGMENTATION: Habitat destruction due to agricultural conversion and development of native prairie habitat. Restriction of fire also reduced available shortgrass prairie. Population may also be limited by availability of microclimatic features. Initial territories have southern exposure; birds may be sensitive to ground temperature or moisture. No studies have investigated a relationship between patch size and nest success or patch size and rates of brood parasitism by Brown-headed Cowbirds (MOLOTHRUS ATER). Cowbird parasitism, however, appears rare (With 1994a).

PREDATION: Nest predation believed to limit productivity. In Saskatchewan, Wyoming, and Colorado, about half of all nests were lost to predators, such as the thirteen-lined ground squirrel (CITELLUS TRIDECEMLINEATUS; see With 1994a). Nests in heavily grazed pasture suffered higher predation rates (up to 75 percent) compared to nests in moderately grazed pasture (up to 60 percent; With 1994a). Both eggs and nestling were depredated.

PESTICIDES: Application of insecticide toxaphene resulted in direct poisoning of nestlings (McEwen and Ells 1975 cited in With 1994a).

DISTURBANCE: May have a relatively high incidence of nest desertion due to human interference. In Saskatchewan, 10.8 percent of nests and 7.5 percent of nestlings may have been abandoned due to human interference (Felske 1971, cited in With 1994a). Individuals, however, vary in response to human disturbance; some allowed approach to within 5 - 10 meters of nest, others flushed within 25 meters (With 1994a).

Short-term Trend: Decline of 10-50%
Short-term Trend Comments: Declines outlined below are apparently continuing in Canada and the northern Great Plains (Sauer et al. 2003).

Long-term Trend: Decline of 50-90%
Long-term Trend Comments: A great deal of habitat has been lost over the last century.

Significant declines have occurred in the northern part of the range in the last three to four decades. Breeding Bird Survey data indicate a -13.1% annual decline for the Canadian prairies, 1966-2002, a cumulative decline of more than 99%; and just south of the Canadian border, the Glaciated Missouri Plateau region shows a -6.9% annual decline for the same period, a cumulative decline of over 92%. However, the data for all United States surveys indicate a positive, albeit not statistically significant trend, 1966-2002. Survey-wide data show a -2% annual decline, not statistically significant (Sauer et al. 2003).

Other NatureServe Conservation Status Information

Inventory Needs: Locate nesting pairs; determine population abundance.

Protection Needs: Protect grassland habitat.

Distribution
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Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) BREEDING: southeastern Alberta, southern Saskatchewan, northern North Dakota and (previously) southwestern Minnesota, south through Montana to southeastern Wyoming, northeastern Colorado, Oklahoma, northwestern Nebraska, and Manitoba (With 1994a, AOU 1998). NON-BREEDING: primarily from western Oklahoma, western Kansas, southeastern Arizona, and central New Mexico south through Sonora and Chihuahua to northern Durango (With 1994a, AOU 1998). Rarely in Idaho, Utah, Nevada, and ne and coastal California (With 1994a).

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

U.S. & Canada State/Province Distribution
United States AZ, CA, CO, KS, MNextirpated, MT, ND, NE, NM, OK, SD, TX, WY
Canada AB, SK

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; WILDSPACETM 2002


U.S. Distribution by County Help
State County Name (FIPS Code)
CO Baca (08009), Cheyenne (08017), El Paso (08041), Elbert (08039), Huerfano (08055), Kiowa (08061), Larimer (08069), Las Animas (08071), Lincoln (08073), Logan (08075), Morgan (08087), Otero (08089), Washington (08121), Weld (08123)
ID Canyon (16027), Fremont (16043)
MT Beaverhead (30001), Blaine (30005), Broadwater (30007), Chouteau (30015), Daniels (30019), Fergus (30027), Glacier (30035), Golden Valley (30037), Hill (30041), Judith Basin (30045), Lewis and Clark (30049), Liberty (30051), Madison (30057), McCone (30055), Musselshell (30065), Petroleum (30069), Phillips (30071), Pondera (30073), Roosevelt (30085), Rosebud (30087), Sheridan (30091), Stillwater (30095), Sweet Grass (30097), Teton (30099), Toole (30101), Valley (30105), Wheatland (30107), Yellowstone (30111)
ND Bowman (38011), Golden Valley (38033)*
NE Kimball (31105), Sioux (31165)
NM Otero (35035)
SD Harding (46063)*
WY Albany (56001), Big Horn (56003)*, Campbell (56005), Carbon (56007), Converse (56009), Crook (56011), Fremont (56013), Goshen (56015), Johnson (56019), Laramie (56021), Natrona (56025), Niobrara (56027), Park (56029), Platte (56031), Sublette (56035), Sweetwater (56037), Weston (56045)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
10 Red Rock (10020001)+, Beaverhead (10020002)+, Big Hole (10020004)+, Jefferson (10020005)+, Madison (10020007)+, Upper Missouri (10030101)+, Upper Missouri-Dearborn (10030102)+, Sun (10030104)+, Two Medicine (10030201)+, Cut Bank (10030202)+, Marias (10030203)+, Willow (10030204)+, Teton (10030205)+, Bullwhacker-Dog (10040101)+, Judith (10040103)+, Fort Peck Reservoir (10040104)+, Upper Musselshell (10040201)+, Middle Musselshell (10040202)+, Flatwillow (10040203)+, Box Elder (10040204)+, Upper Milk (10050002)+, Middle Milk (10050004)+, Big Sandy (10050005)+, Sage (10050006)+, Lodge (10050007)+, Battle (10050008)+, Peoples (10050009)+, Cottonwood (10050010)+, Whitewater (10050011)+, Lower Milk (10050012)+, Frenchman (10050013)+, Beaver (10050014)+, Rock (10050015)+, Porcupine (10050016)+, Prarie Elk-Wolf (10060001)+, Redwater (10060002)+, Poplar (10060003)+, West Fork Poplar (10060004)+, Big Muddy (10060006)+, Brush Lake closed basin (10060007)+, Upper Yellowstone (10070002)+, Upper Yellowstone-Lake Basin (10070004)+, Clarks Fork Yellowstone (10070006)+, Upper Yellowstone-Pompeys Pillar (10070007)+, Upper Wind (10080001)+, Badwater (10080006)+, Upper Bighorn (10080007)+*, Greybull (10080009)+*, Upper Powder (10090202)+, South Fork Powder (10090203)+, Salt (10090204)+, Crazy Woman (10090205)+, Clear (10090206)+, Middle Powder (10090207)+, Little Powder (10090208)+, Lower Yellowstone-Sunday (10100001)+, Big Porcupine (10100002)+, Upper Little Missouri (10110201)+, Boxelder (10110202)+*, Middle Little Missouri (10110203)+*, Antelope (10120101)+, Dry Fork Cheyenne (10120102)+, Upper Cheyenne (10120103)+, Lance (10120104)+, Lightning (10120105)+, Angostura Reservoir (10120106)+, Beaver (10120107)+, Hat (10120108)+, Upper Belle Fourche (10120201)+, Niobrara Headwaters (10150002)+, Upper North Platte (10180002)+, Pathfinder-Seminoe Reservoirs (10180003)+, Medicine Bow (10180004)+, Little Medicine Bow (10180005)+, Sweetwater (10180006)+, Middle North Platte-Casper (10180007)+, Glendo Reservoir (10180008)+, Middle North Platte-Scotts Bluff (10180009)+, Upper Laramie (10180010)+, Lower Laramie (10180011)+, Horse (10180012)+, Middle South Platte-Cherry Creek (10190003)+, Cache La Poudre (10190007)+, Lone Tree-Owl (10190008)+, Crow (10190009)+, Bijou (10190011)+, Middle South Platte-Sterling (10190012)+, Beaver (10190013)+, Pawnee (10190014)+, Upper Lodgepole (10190015)+, Lower Lodgepole (10190016)+, Sidney Draw (10190017)+, Arikaree (10250001)+, North Fork Republican (10250002)+
11 Chico (11020004)+, Huerfano (11020006)+, Horse (11020008)+, Purgatoire (11020010)+, Big Sandy (11020011)+, Rush (11020012)+, Two Butte (11020013)+, Cimarron headwaters (11040001)+, Sand Arroyo (11040004)+
13 Tularosa Valley (13050003)+
14 Upper Green (14040101)+, Upper Green-Slate (14040103)+, Bitter (14040105)+, Blacks Fork (14040107)+, Great Divide closed basin (14040200)+
17 Lower Henrys (17040203)+, Beaver-Camas (17040214)+, Middle Snake-Succor (17050103)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: McCown's longspur, Emberizidae.
Reproduction Comments: The breeding season extends approximately from mid-March through mid-October (Mickey 1943, Giezentanner and Ryder 1969, Felske 1971, Creighton 1974, Salt and Salt 1976, With 1994a), but may remain on the breeding grounds as late as mid-November in some locations (Johnsgard 1980). The female incubates three to four, sometimes up to six, eggs for 12 days. In northeastern Colorado, usual clutch size was three (With 1994a). Nestlings are altricial. Young are tended by both adults, leave nest in 10 days, and fly 12 days after hatching (Terres 1980). Second broods were reported in northcentral Colorado and in Montana (DuBois 1935, Strong 1971). Second broods may be initiated as soon as three weeks after fledging of the initial brood, but may be limited by female energy reserves (Felske 1971, With 1994a).
Ecology Comments: Area requirements vary by region. Reported territory sizes were 0.6 hectares in southeastern Wyoming (Greer and Anderson 1989), 0.5-1.0 hectares in Saskatchewan (Felske 1971), and 1-1.5 hectares in central Colorado (Wiens 1970, 1971; With 1994a). Pairs often nest near each other (Mickey 1943, Felske 1971). In winter may be seen with flocks of horned larks.
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: Y
Mobility and Migration Comments: Flocks migrate from winter range in Texas in March-early April, from Arizona late February-early May. Reaches nesting areas in April, early to mid-April in Wyoming (Greer and Anderson 1989), mid- to late April in Montana. In winter may be seen with flocks of horned larks.
Terrestrial Habitat(s): Cropland/hedgerow, Grassland/herbaceous
Habitat Comments: Sparse short-grass plains, plowed and stubble fields, and areas of bare or nearly bare ground (AOU 1983). Use grasslands with little litter (Felske 1971) and low vegetation cover (DuBois 1935, Creighton 1974), such as that provided by shortgrass or heavily grazed mixed-grass prairie (Saunders 1914; Finzel 1964; Wiens 1970; Maher 1973, 1974; Creighton 1974; Oberholser 1974; Porter and Ryder 1974; Stewart 1975; With 1994a; Prescott and Wagner 1996). Cultivated lands also may be utilized, including small-grain stubble fields, minimum- and conventional-tilled land, and summer fallow fields (Felske 1971, Stewart 1975, Martin in prep.), although, historically, agricultural lands were avoided (DuBois 1935, Mickey 1943). Early-season abundance of nesting birds in cropland fields in southcentral Alberta showed a positive correlation with percent bare ground, and productivity appeared to be negatively correlated with the vertical density of forbs (Martin in prep.). Often breed on high, barren hillsides with southern exposures (Giezentanner 1970a,b; Felske 1971; Creighton 1974). Blue grama (BOUTELOUA GRACILIS) and buffalo grass (BUCHLOE DACTYLOIDES) are dominant plants in nesting areas (DuBois 1935, Cassel 1952, Creighton 1974).

Nests usually in a scrape on the ground at the base of a bush or clump of grass, or beside cattle dung. Nests beside shrubs may be subject to heavy predation by ground squirrels (With 1994a). Nests tend to be oriented to the north (With and Webb 1993), and about one-third to one-half of nests are placed near clumps of grass, shrubs, plains prickly pear (OPUNTIA POLYACANTHA), or cowpies (DuBois 1935, Mickey 1943, With 1994b). However, shrubs and prickly pear near the nest may facilitate depredation by providing protective cover to predators. In northcentral Colorado, for example, 75-80 percent of nests placed near shrubs or prickly pear were depredated (With 1994b). Nests depredated during incubation had six times more shrub cover within 1 meter of the nest than did successful nests.

In northcentral Colorado, nests were exposed completely to solar radiation at midday and had 45 percent total exposure per day (With and Webb 1993). High exposure to solar radiation may ameliorate cold stresses associated with an early breeding season. Nests constructed later in the season were more likely to be constructed near vegetative cover than those constructed earlier in the season (With and Webb 1993). In southeastern Wyoming, percent vegetation coverage within 5 centimeters of the ground was higher in occupied territories than in unoccupied territories (Greer and Anderson 1989). Occupied territories also had fewer cowpies, less lichen, and lower forb coverage than unoccupied areas.

Adult Food Habits: Granivore, Invertivore
Immature Food Habits: Granivore, Invertivore
Food Comments: Forages on the ground for seeds and insects. Primarily insectivorous in breeding season; diet consists mainly of orthopterans and beetles.
Adult Phenology: Diurnal
Immature Phenology: Diurnal
Length: 15 centimeters
Weight: 23 grams
Economic Attributes Not yet assessed
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Management Summary
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Stewardship Overview: Keys to management include providing short, sparsely vegetated native grasslands of adequate size. Mixed-grass areas can be made suitable for nesting by implementing moderate to heavy, or season-long grazing.
Preserve Selection & Design Considerations: Protect habitat from agricultural and urban development (Oberholser 1974, With 1994a). Provide areas of adequate size to support multiple territories (0.5-1.5 hectares per territory, depending on geographic location), as pairs often nest near each other (Mickey 1943, Wiens 1970, Felske 1971, Greer and Anderson 1989, With 1994a).
Management Requirements: Provide areas with little litter and short, sparse vegetation with low forb cover (DuBois 1935; Felske 1971; Maher 1973,1974; Stewart 1975; With 1994a; Martin in prep.). Prescribed prairie burns have been suggested for historically burned areas where fire has been suppressed (Krause 1968, Oberholser 1974, With 1994a).

GRAZING: Protect vegetation that is already sparse and short from overgrazing (Oberholser 1974), especially in areas of low precipitation (Ryder 1980). Graze areas where grass is too tall or thick for breeding (Giezentanner 1970a,b; Stewart 1975; Kantrud and Kologiski 1982). Did not breed on idle mixed-grass in Saskatchewan, and preferred heavily grazed pastures over lightly or moderately grazed pastures (Felske 1971). Grazing can improve habitat by providing shorter, sparser vegetation (Giezentanner 1970a, Stewart 1975, Kantrud and Kologiski 1982, Bock et al. 1993). Heavily grazed areas with aridic boroll soils and moderately grazed areas with aridic ustoll soils appeared to be ideal nesting habitat in portions of North Dakota, Montana, Wyoming, Colorado, and Nebraska (Kantrud and Kologiski 1982). In Alberta, preferred continuously grazed (season-long) native pastures, and were fairly common in native pastures grazed in early summer (Prescott et al. 1993, Prescott and Wagner 1996). Infrequently occupied spring-grazed (late April to mid-June) pastures of crested wheatgrass (AGROPYRON CRISTATUM), and they avoided deferred-grazed (grazed after 15 July) native pastures. In northcentral Alberta, used moderately to heavily grazed grasslands on drier, sandier sites than those used by Chestnut-collared Longspurs (CALCARIUS ORNATUS) (Wershler et al. 1991). Nesting birds in Alberta and Saskatchewan were found to favor season-long grazed native pasture over areas managed with complementary grazing (early-season grazing on crested wheatgrass with cattle rotated through several native-grassland paddocks for the remainder of the summer) (Dale and McKeating 1996). Did not breed on idle mixed-grass in Saskatchewan, and preferred heavily grazed pastures over lightly or moderately grazed pastures (Felske 1971). Summer-grazed areas were preferred over winter-grazed areas in Colorado shortgrass prairie (Giezentanner and Ryder 1969; Giezentanner 1970a,b; Wiens 1970). However, overgrazing may be detrimental (Oberholser 1974), particularly in arid, sparse shortgrass (Ryder 1980). In southern Saskatchewan, were found in equal abundances in tame and native pastures (Duncan and Davis in press).

Management Research Needs: Little is known about the short- or long-term effects of burning on populations. Some authors have suggested that prairie fire suppression has contributed to the population decline of the species (Krause 1968, Oberholser 1974, With 1994a).
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: 30Oct1999
NatureServe Conservation Status Factors Author: JENNINGS, R., and J.D. REICHEL; Revisions by M. KOENEN and D.W. MEHLMAN
Management Information Edition Date: 01Jan1999
Management Information Edition Author: DECHANT, J., M. SONDREAL, D. JOHNSON, L. IGL, C. GOLDADE, P.A. RABIE, AND B. EULISS. REVISIONS BY M. KOENEN AND D.W. MEHLMAN
Management Information Acknowledgments: Parts of this abstract were originally researched and written by staff of the Northern Prairie Wildlife Research Center and published as Dechant et al. (1999). Additional 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: 18Jan1995
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).

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