Vireo griseus - (Boddaert, 1783)
White-eyed Vireo
Other English Common Names: white-eyed vireo
Taxonomic Status: Accepted
Related ITIS Name(s): Vireo griseus (Boddaert, 1783) (TSN 178991)
French Common Names: Viréo aux yeux blancs
Spanish Common Names: Vireo Ojo Blanco
Unique Identifier: ELEMENT_GLOBAL.2.103052
Element Code: ABPBW01020
Informal Taxonomy: Animals, Vertebrates - Birds - Perching Birds
 
Kingdom Phylum Class Order Family Genus
Animalia Craniata Aves Passeriformes Vireonidae Vireo
Genus Size: D - Medium to large genus (21+ 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: Vireo griseus
Taxonomic Comments: Puebla and Veracruz populations often have been recognized as a distinct species, V. PERQUISITOR (Veracruz Vireo) (AOU 1983). Species boundaries in the white-eyed vireo complex (GRISEUS, CRASSIROSTRIS, PALLENS, BAIRDI, CARIBAEUS, MODESTUS, GUNDLACHII, LATIMERI, and NANUS) are poorly understood (AOU 1998). See Johnson et al. (1988) and Murray et al. (1994) for analyses of the phylogenetic relationships among vireos.
Conservation Status
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NatureServe Status

Global Status: G5
Global Status Last Reviewed: 10Apr2016
Global Status Last Changed: 03Dec1996
Ranking Methodology Used: Ranked by inspection
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 Alabama (S5B,S3N), Arkansas (S4B,S4N), Colorado (SNA), Connecticut (S5B), Delaware (S5B), District of Columbia (S1B,S2S4N), Florida (SNR), Georgia (S5), Illinois (S5), Indiana (S4B), Iowa (S2B,S3N), Kansas (S3B), Kentucky (S5B), Louisiana (S5B), Maryland (S5B), Massachusetts (S2S3B,S4N), Michigan (S4), Mississippi (S5B,S5N), Missouri (SNRB), Nebraska (SH), New Jersey (S4B), New York (S4B), North Carolina (S5B,S1N), Ohio (S5), Oklahoma (S5B), Pennsylvania (S4B), Rhode Island (S4B), South Carolina (S4?B), Tennessee (S4), Texas (S5B), Virginia (S5), West Virginia (S5B), Wisconsin (SNA)

Other Statuses

IUCN Red List Category: LC - Least concern

NatureServe Global Conservation Status Factors

Range Extent Comments: BREEDING: central Iowa, southeastern Minnesota (rarely), southern Wisconsin, southern Michigan, extreme southern Ontario, southern New York, and southern Massachusetts, south to southern Mexico (San Luis Potosi, Hidalgo), southern Texas, Gulf Coast, southern Florida and west to eastern Nebraska (formerly), eastern Kansas, central Oklahoma, west-central Texas, and Coahuila (AOU 1998). NON-BREEDING: central Texas, the Gulf states, and extreme southeastern Virginia (Dismal Swamp) south to Guatemala, Belize, and northwestern Honduras (casually to western Panama); also in Bermuda, Bahamas, Jamaica, Cuba, Cayman Islands, Puerto Rico, and St. John (Hopp et al. 1995, AOU 1998). RESIDENT: Bermuda (subspecies BERMUDIANUS) (Hopp et al. 1995). Casual north to North Dakota, southern Manitoba, southern Minnesota, northern Michigan, southern Quebec, Maine, and Nova Scotia, west to California, Utah, Arizona, Colorado, southern New Mexico, Chihuahua, and south to Costa Rica, Panama, Puerto Rico (including Mona Island) and the Virgin Islands (St. John); sight report for Socorro (Revillagigedo Islands) (AOU 1998).

Overall Threat Impact Comments: PREDATION: Potential predators of nests and fledglings include snakes (e.g. Rat Snakes, ELAPHE OBSOLETA), Blue Jays (CYANOCITTA CRISTATA), mice (PEROMYSCUS sp.), Eastern Chipmunks (TAMIAS STRIATUS), Raccoons (PROCYON LOTOR), Virginia Opossums (DIDELPHIS MARSUPIALIS), and Striped Skunks (MEPHITIS MEPHITIS). Short-tailed Hawks (BUTEO BRACHYURUS) are confirmed predators (Ogden 1974). In Bermuda, fledglings sometimes get entangled in golden-silk spider webs (NEPHILA CLAVIPES; Forbush and May 1939 cited in Hopp et al. 1995). NEST PARASITISM: Observed rates of Brown-headed Cowbird nest parasitism vary from 40% in Louisiana (Goertz 1977), to 48.9% in Virginia (Hopp et al. 1995), to 83% in Illinois (Graber et al. 1985). Parasitized host nests typically fledge only cowbird young (Hopp et al. 1995). OTHER: During migration, large numbers are sometimes killed during severe weather. An estimated 1800 individuals were killed by thunderstorms and a tornado in Louisiana during spring migration (Weidenfeld and Weidenfeld 1995). Migrating individuals are killed by colliding with towers (Crawford 1978, Taylor and Anderson 1973, Taylor and Kershner 1986).

Short-term Trend Comments: Surveywide analysis of BBS data for the period 1966-1998 indicates a statistically insignificant decline of 0.1%/year in eastern North America. The eastern BBS region showed a positive population trend and the central BBS region exhibited a negative trend during this time period (Sauer et al. 1999). Population increases are likely due to an increase in shrub habitat (Hopp et al. 1995).

Other NatureServe Conservation Status Information

Distribution
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Global Range: BREEDING: central Iowa, southeastern Minnesota (rarely), southern Wisconsin, southern Michigan, extreme southern Ontario, southern New York, and southern Massachusetts, south to southern Mexico (San Luis Potosi, Hidalgo), southern Texas, Gulf Coast, southern Florida and west to eastern Nebraska (formerly), eastern Kansas, central Oklahoma, west-central Texas, and Coahuila (AOU 1998). NON-BREEDING: central Texas, the Gulf states, and extreme southeastern Virginia (Dismal Swamp) south to Guatemala, Belize, and northwestern Honduras (casually to western Panama); also in Bermuda, Bahamas, Jamaica, Cuba, Cayman Islands, Puerto Rico, and St. John (Hopp et al. 1995, AOU 1998). RESIDENT: Bermuda (subspecies BERMUDIANUS) (Hopp et al. 1995). Casual north to North Dakota, southern Manitoba, southern Minnesota, northern Michigan, southern Quebec, Maine, and Nova Scotia, west to California, Utah, Arizona, Colorado, southern New Mexico, Chihuahua, and south to Costa Rica, Panama, Puerto Rico (including Mona Island) and the Virgin Islands (St. John); sight report for Socorro (Revillagigedo Islands) (AOU 1998).

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 AL, AR, CO, CT, DC, DE, FL, GA, IA, IL, IN, KS, KY, LA, MA, MD, MI, MO, MS, NC, NE, NJ, NY, OH, OK, PA, RI, SC, TN, TX, VA, WI, WV

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; WILDSPACE TM 2002


U.S. Distribution by County Help
State County Name (FIPS Code)
KS Allen (20001), Cherokee (20021), Crawford (20037), Douglas (20045), Johnson (20091), Labette (20099), Linn (20107), Montgomery (20125), Neosho (20133), Wyandotte (20209)
NE Cass (31025)*, Sarpy (31153)*
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
10 Lower Platte (10200202)+*, Lower Kansas (10270104)+, Lower Marais Des Cygnes (10290102)+
11 Elk (11070104)+, Upper Neosho (11070204)+, Middle Neosho (11070205)+, Spring (11070207)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: A small bird (vireo).
Reproduction Comments: Three to five eggs are laid from early April through late May, although renesting can extend into late July (Bent 1950, Hopp et al. 1995). Known to produce two broods per season, and attempt to nest up to four times. The average clutch size of 103 sets of eggs collected from throughout the range was 3.74 eggs. One egg is laid per day until the clutch is complete; incubation begins after the penultimate or ultimate egg is laid. Both sexes incubate the eggs (13-15 days), and brood and feed the young. Young leave the nest 9-11 days after hatching at which time they are capable of short-distance flight. In Virginia, 29.8% of nests observed over a seven-year period fledged young. Successful nests produced 3.2 young per nest; whereas all nests (including unsuccessful) produced an average of 0.96 young/nest (Hopp et al. 1995).
Ecology Comments: DENSITY/TERRITORIALITY: Territorial during the breeding season; size of breeding territories vary with habitat quality. Territory size varied from 0.13 hectares in a swamp thicket to 1.4 hectares in a forest edge in Illinois (Graber et al. 1985), and averaged 1.3 hectares in Florida (Bradley 1980). Also territorial on wintering grounds (Greenberg et al. 1993, Rappole and Warner 1980). Average size of winter territory on the Yucatan Peninsula is approximately 0.5 hectares (Greenberg et al. 1993). Density during the breeding season has been reported to be 1.2 pairs/10 hectares in Chestnut Oak (QUERCUS PRINUS) forest in the Smoky Mountains (Wilcove 1988), 18 birds/40.5 hectares in bottomland forests of Arkansas (James and Neal 1986), and to vary from <1-24 birds/40.5 hectares in Illinois, with lowest densities occurring in forested habitats and highest in shrub and forest edge habitats (Graber et al. 1985).

SITE FIDELITY: Exhibits strong breeding site fidelity. In Virginia, 97% of returning males re-occupied their previously held territories. Females returned to the study area, but not to the same territory; none paired with the same male as the previous year (Hopp et al. 1999). Also exhibits site fidelity to wintering sites. Banded individuals have returned to the same wintering site in consecutive years in Veracruz, Mexico (Rappole and Warner 1980).

POPULATION PARAMETERS: Lives to be at least 9 years old (Hopp et al. 1999).

PARASITES: Known ectoparasites include lice (PHILOPTERUS SUBFLAVESCENS and RICINUS sp.) and louse-flies (ORNITHOMYA ANCHINEURIA). Can also be infected with encephalitis (Hopp et al. 1995).

Non-Migrant: Y
Locally Migrant: Y
Long Distance Migrant: Y
Mobility and Migration Comments: Northern populations are migratory, completely leaving the breeding range, whereas as southern populations are either sedentary or partially migratory. Migration across the United States extends from mid-March through mid-May in spring, and from mid-September through mid-October in fall (Hopp et al. 1995). Arrives on wintering grounds in October and November, and departs in April and March (Greenberg et al. 1993, Raffaele 1989, Rogers et al. 1986, Winker et al. 1992). Early morning collections of birds killed at towers indicate that migration is nocturnal (Crawford 1978, Taylor and Anderson 1973, Taylor and Kershner 1986).
Palustrine Habitat(s): Riparian
Terrestrial Habitat(s): Forest - Hardwood, Old field, Shrubland/chaparral, Woodland - Hardwood
Habitat Comments: BREEDING: Inhabits early-late successional, shrubby habitats such as deciduous scrub, old fields, abandoned pastures, regenerating clearcuts or other heavily logged areas, drainage and streamside thickets, forest edges, reclaimed strip mines, and mangrove swamps (Bent 1950, Bradley 1980, Graber et al. 1985, Hopp et al. 1995, Mumford and Keller 1984, Palmer-Ball 1996). In east Texas, positively associated with high shrub density and species diversity, and foliage density (Conner et al. 1983). In Virginia, prefers habitats with extensive undergrowth, shrubs, and tree saplings interspersed with widely spaced taller trees (Hopp et al. 1995). Birds inhabiting the Atlantic coastal region of Georgia and the Carolinas prefer scrub lacking an overstory, whereas birds ranging from Alabama to Louisiana appear to prefer edge habitat (S. L. Hopp, pers. comm.). Nest is typically placed in a Y-shaped horizontal branch of a deciduous tree or shrub, 0.3-2.11 m above the ground (Hopp et al. 1995).

NON-BREEDING: Considered a habitat generalist on the wintering grounds. Observed in all habitat types surveyed on the Yucatan Peninsula, including field, pasture, acahual (shrubby, early successional habitat), semi-deciduous forest, semi-evergreen forest, moist tropical forest, mangrove forest and coastal scrub (Lynch 1989). In a habitat-use study of three habitat types on the Yucatan Peninsula (pasture, acahual and subtropical dry forest), observed most frequently in the latter (Greenberg 1992). Captured most frequently in pine savanna and early successional scrub in Belize (Petit et al. 1992). In Veracruz, Mexico, occupied young (1-10 m tall) and old (10-20 m tall) second-growth forest, as well as undisturbed evergreen tropical forest (Rappole and Warner 1980).

Adult Food Habits: Frugivore, Invertivore
Immature Food Habits: Frugivore, Invertivore
Food Comments: Forages among woody vegetation, capturing invertebrates and plucking fruit. The contents of 67 stomachs collected during migration and the breeding season contained more animal than plant matter. Lepidoptera (principally caterpillars), Coleopterans, Arachnids, Hemiptera, and Homoptera comprised the bulk of the animal prey (Nolan and Wooldridge 1962). An examination of 221 stomachs collected throughout the year also illustrates the importance of invertebrates in the diet. Nearly 90% of the diet was composed of animal matter, principally insects and spiders (Bent 1950). The consumption of plant material varies from 9% of the diet in winter to 32% of the diet in spring (Martin et al. 1951). Fruits eaten include those of grape (VITIS), sumac (RHUS), dogwood (CORNUS), and wax myrtle (MYRICA; Bent 1950). On the wintering grounds, also feeds on fruit of BURSERA SIMARUBA and CORDIA CURASSAVICA (Greenberg et al. 1993, Stiles and Skutch 1989). Moisture is obtained principally from food, though will take dew from foliage (Hopp et al. 1995).
Adult Phenology: Diurnal
Immature Phenology: Diurnal
Length: 13 centimeters
Weight: 11 grams
Economic Attributes Not yet assessed
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Management Summary
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Stewardship Overview: Perhaps a result of its preference for successional habitats and forest edges, White-eyed Vireo nests are heavily parasitized by Brown-headed Cowbirds (MOLOTHRUS ATER) and are preyed upon by numerous predators. North American Breeding Bird Survey (BBS) data do not indicate a significant population change between 1966 and 1998. Preferred habitat can be readily created by opening the forest canopy, either by thinning or clearcutting, and allowing cultivated/pastured land to go fallow. Relatively wide, forested riparian corridors provide preferred breeding habitat, as do isolated woodlots of varying sizes. Due to strong breeding site fidelity, year-to-year maintenance of preferred breeding habitat is important in managing for this species.
Restoration Potential: Readily colonizes shrubby, successional habitats. In the early 1900s, expanded its range into the open-canopied forests of the central Appalachians following the demise of the American chestnut (CASTANEA DENTATA; Bent 1950).
Preserve Selection & Design Considerations: Although classified as a forest edge/interior, area-insensitive species (Freemark and Collins 1992), observed only in woodlots ranging from 28-65 hectares in area in a study of isolated east-central Illinois woodlots ranging from 1.6-600 hectares in size (Blake and Karr 1987). Habitat use is influenced by canopy coverage and shrub density. In oak (QUERCUS)-hickory (CARYA) forest in Illinois, found to be more abundant in relatively shrubby, selectively cut stands than uncut stands (Robinson and Robinson 1999). In Loblolly Pine (PINUS TAEDA)-Shortleaf Pine (PINUS ECHINATA)-hardwood forest of east Texas, presence positively correlated with shrub density and species diversity, and foliage density (Conner et al. 1983). Significantly more abundant in young clearcuts (7-10 years post-harvest) than older clearcuts (17-19 years post-harvest) in Arkansas (Kellner 1996). In South Carolina, observed more frequently in hardwood stands surrounded by fields/early successional habitats than hardwood stands embedded within pine plantations, irregardless of size of hardwood stand (Kilgo et al. 1997). Tends to inhabit wider riparian forests with greater frequency than narrow riparian forests. On the Delmarva Peninsula of Maryland and Delaware, the probability of encountering vireos in riparian forests ranging from £50-800 m wide increased positively with forest width (Keller et al. 1993). The same relationship between riparian forest width and vireo density was observed in bottomland forests of South Carolina that ranged from less than 50 to more than 1000 m wide; vireo counts were highest in stands >1000 m wide (Kilgo et al. 1998). Vireos occurred in all three riparian forest widths surveyed in Georgia (<350, 400-700, and >1000 m), but highest densities were observed in stands 400-700 m wide (Hodges and Krementz 1996). Forest-dividing corridors, such as roads and powerlines that break the forest canopy, create favorable habitat. In New Jersey, observed with similar frequency adjacent to corridors averaging 8, 16 and 23 meters in width (Rich et al. 1994). In eastern Tennessee, however, transmission line corridor width had a significant impact on vireo distribution. Whereas none were observed in narrow corridors (12 and 31.5 m wide) they were sighted in wide corridors (61 and 91.5 m wide; Anderson et al. 1977).
Management Requirements: Early successional vegetation that dominates following clearcutting provides excellent habitat in east Texas pine-hardwood forests. Frequent thinning of pole/mature stands enhances shrub vegetation, improving habitat conditions (Conner et al. 1983). Fire exclusion in Southeastern pinelands allows previously fire-suppressed hardwoods to flourish, initially benefiting this species. However, habitat changes associated with long-term fire exclusion (>15 years) do not (Engstrom et al. 1984). Any form of land management that favors successional vegetation will benefit this species. Because the value of scrubby habitat is not often recognized, public land managers may need to include public education in their efforts to manage for early successional habitats (S. L. Hopp, pers. comm.).
Monitoring Requirements: The density of calling males or breeding pairs can be determined by point counts or spot mapping techniques. Because calling rates vary across the season and nesting cycle, caution must be exercised when conducting aural surveys. For example, adults vocalize less often when feeding young and fledglings. Furthermore, groups of males inhabiting an area alternate between quiet and vocal periods. The species could be missed if the duration of a survey coincided with a non-vocalizing period. Repeated visits to an area may be necessary to accurately determine presence/absence and/or population size based on vocalizing birds (S. L. Hopp, pers. comm.).
Management Research Needs: No known management research programs aimed specifically at this species.
Biological Research Needs: Studies are needed on regional differences in reproductive success, Brown-headed Cowbird parasitism, natal dispersal and survival, winter ecology, and migration routes (Hopp et al. 1995, Hopp et al. 1999).
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 Author: PALIS, J.
Management Information Edition Date: 28Jun2000
Management Information Edition Author: PALIS, J: REVISIONS BY S. CANNINGS
Management Information Acknowledgments: The author thanks Dr. Steven L. Hopp for for reviewing an earlier draft of this document. Support for the preparation of this abstract was provided by the U.S. Air Force Arnold Engineering Development Center through The Nature Conservancy's Tennessee Field Office and Wings of the Americas program.
Element Ecology & Life History Edition Date: 18Jan1995
Element Ecology & Life History Author(s): HAMMERSON, G. AND J. PALIS

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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  • Alabama Breeding Bird Atlas 2000-2006 Homepage. 2009. T.M. Haggerty (editor), Alabama Ornithological Society. Available at http://www.una.edu/faculty/thaggerty/BBA%20website/Index.htm.

  • Alabama Ornithological Society. 2006. Field checklist of Alabama birds. Alabama Ornithological Society, Dauphin Island, Alabama. [Available online at http://www.aosbirds.org/documents/AOSChecklist_april2006.pdf ]

  • Allen, C. R., S. Demarais, and R. S. Lutz. 1994. Red imported fire ant impact on wildlife: an overview. The Texas Journal of Science 46(1):51-59.

  • American Ornithologists Union (AOU). 1998. Check-list of North American Birds. 7th edition. American Ornithologists Union, Washington, D.C. 829 pages.

  • American Ornithologists' Union (AOU), Committee on Classification and Nomenclature. 1983. Check-list of North American Birds. Sixth Edition. American Ornithologists' Union, Allen Press, Inc., Lawrence, Kansas.

  • 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/.

  • Anderson, S. H., K. Mann, and H. H. Shugart, Jr. 1977. The effect of transmission-line corridors on bird populations. American Midland Naturalist 97:216-221.

  • Andrews, R. R. and R. R. Righter. 1992. Colorado Birds. Denver Museum of Natural History, Denver. 442 pp.

  • B83COM01NAUS - Added from 2005 data exchange with Alberta, Canada.

  • BUCKELEW, A. AND G. HALL. 1994. WV BREEDING BIRD ATLAS. UNIVERSITY OF PITTSBURGH PRESS.

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

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