Porzana carolina

A medium-sized (8-9 ¾ inches) rail, the Sora is most easily identified by its mottled brown back, gray neck, and black face and throat. Other field marks include a bright yellow bill, brown striped flanks, and a short tail. Male and female Soras are similar to one another in all seasons. The Sora breeds across much of Canada and the northern half of the United States. In the west, this species’ range extends as far south as central Arizona, while in the east this species breeds locally as far south as Virginia. During the winter, Soras may be found along the Pacific coast south of Oregon, along the Atlantic and Gulf coasts south of Delaware, and in the tropics as far south as northern South America. Soras breed in shallow freshwater wetland habitats. In winter, this species is less tied to freshwater, and may be found in ponds or small lakes, freshwater or saltwater marshes, flooded grasslands, and mangrove wetlands. Soras primarily eat a variety of plant and animal foods, including seeds and small aquatic invertebrates. In appropriate habitat, Soras may be seen wading in shallow water while foraging for food on the surface. If these birds are more hidden, perhaps beneath tall marsh grasses, it may still be possible to hear their call, a high tooting “ker-wee?” repeated many times in succession. Soras are primarily active during the day, although they may be heard calling at night.

Threat Status: Least concern

Breeding range:

The sora (Porzana carolina) occupies much of temperate North America, ranging (in the west) as far north as the Northwest Territories, to the southern extremes of Arizona and New Mexico. The breeding range of Porzana carolina narrows in the east, occurring from Canada's Maritime provinces south to Maryland, USA.

Overwintering range:

As wetlands freeze in the breeding range of Porzana carolina, this species moves south to overwinter, occupying the southern United States from Arizona to Florida, and also throughout Mexico. In addition, many individuals migrate across the Gulf of Mexico and Caribbean Sea to overwinter in South America.

The coastline of California hosts Porzana carolina year round.

(Kaufman, 1996)

Biogeographic Regions: nearctic (Native )

S Alaska to n Baja and s US; winters to W Indies and n S Am..

(key to state/province abbreviations)
UNITED STATES AL AZ AR CA CO CT DE FL GA HI ID IL IN IA KS KY LA ME MD MA MI MN MS MO MT NE NV NH NJ NM NY NC ND OH OK OR PA RI SC SD TN TX UT VT VA WA WV WI WY DC PR VI

CANADA

AB BC MB NB NT NS ON PE PQ SK YK

MEXICO

Ags. B.C.N. B.C.S. Camp. Chis. Chih. Coah. Col. Dgo. Edo. Méx. Gto. Gro. Hgo. Jal. Mex. Mich. Mor. Nay. N.L. Oax. Pue. Qro. Q.R. S.L.P. Sin. Son. Tab. Tamps. Tlax. Ver. Yuc. Zac. D.F.

According to field guides, soras occur throughout most of North America [10,44]. Soras breed from Nova Scotia northeast to southern Yukon and Northwest Territories, south to California, Arizona, and New Mexico and northeast to Pennsylvania and New England. Sora wintering grounds include the northern portions of South America, including Ecuador, Columbia, and Venezuela, north through Central America and Mexico to southern California in the West and coastal regions of the Southeast. From southern Kansas south to northern and eastern Texas and east through the inland areas of the southeastern United States, soras are typically only observed during migration in the spring and fall. In a few areas of the western United States, including central California and areas of Arizona and New Mexico, soras may occur year round [10,44]. A general map of the sora's distribution can be found at Cornell's All About Birds website.

The following lists are speculative and are based on the habitat characteristics and species composition of communities soras are known to occupy during migration and on breeding and wintering grounds. There is not conclusive evidence that soras occur in all the habitat types listed, and some community types, especially those used rarely, may have been omitted.

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This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

BLM PHYSIOGRAPHIC REGIONS [5]:

1 Northern Pacific Border

2 Cascade Mountains

3 Southern Pacific Border

4 Sierra Mountains

5 Columbia Plateau

6 Upper Basin and Range

7 Lower Basin and Range

8 Northern Rocky Mountains

9 Middle Rocky Mountains

10 Wyoming Basin

11 Southern Rocky Mountains

12 Colorado Plateau

13 Rocky Mountain Piedmont

14 Great Plains

15 Black Hills Uplift

16 Upper Missouri Basin and Broken Lands

Breeding range:

The sora (Porzana carolina) occupies much of temperate North America, ranging (in the west) as far north as the Northwest Territories, to the southern extremes of Arizona and New Mexico. The breeding range of P. carolina narrows in the east, occurring from Canada's Maritime provinces south to Maryland, USA.

Overwintering range:

As wetlands freeze in the breeding range of P. carolina, this species moves south to overwinter, occupying the southern United States from Arizona to Florida, and also throughout Mexico. In addition, many individuals migrate across the Gulf of Mexico and Caribbean Sea to overwinter in South America.

The coastline of California hosts P. carolina year round.

(Kaufman, 1996)

Biogeographic Regions: nearctic (Native )

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

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Breeding

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: BREEDS: southeastern Alaska to northern Saskatchewan and Newfoundland, south locally to northwestern Baja California, southern New Mexico, eastern Colorado, southern Missouri, central Ohio, and Maryland. NORTHERN WINTER: regularly from central California to southern Texas, Gulf Coast, and South Carolina, south through Middle America and West Indies to South America (west of Andes to central Peru, east of Andes to eastern Colombia, eastern Ecuador, Venezuela, and Guyana. (AOU 1983).

Sexually monomorphic. Length 20-30 cm (8-10"). In its breeding plumage, the sora's throat and face are black, with a short, yellowish bill. The breast and nape of neck are gray. The back is mottled brown and the belly displays black and white barring.

Immature and non-breeding plumages are plainer and buff colored with no black on throat or face. While in this plumage, the throat is white and the breast is light brown. The legs of Porzana carolina are yellowish green. The tail is usually held erect while walking and flying.

(Godfrey, 1986; Semenchuk, 1992)

The body of a sora is suited for the marshy habitat that they occupy. Lateral compression of the body offers easy travel through dense vegetation. The sora possesses short, round wings which offer seemingly weak, but highly maneuverable flight through tangled vegetation. Strong legs, with long slender toes on provide Porzana carolina with a strong walking and running ability amongst tangled wetland vegetation. Although this species prefers walking to flying, its long distance capabilities are evident in its migration, often crossing the Gulf of Mexico and the Caribean.

(Semenchuk, 1992; Kaufman, 1996)

Sexually monomorphic. Length 20-30 cm (8-10"). In its breeding plumage, the sora's throat and face are black, with a short, yellowish bill. The breast and nape of neck are gray. The back is mottled brown and the belly displays black and white barring.

Immature and non-breeding plumages are plainer and buff colored with no black on throat or face. While in this plumage, the throat is white and the breast is light brown. The legs of P. carolina are yellowish green. The tail is usually held erect while walking and flying.

(Godfrey, 1986; Semenchuk, 1992)

The body of a sora is suited for the marshy habitat that they occupy. Lateral compression of the body offers easy travel through dense vegetation. The sora possesses short, round wings which offer seemingly weak, but highly maneuverable flight through tangled vegetation. Strong legs, with long slender toes on provide P. carolina with a strong walking and running ability amongst tangled wetland vegetation. Although this species prefers walking to flying, its long distance capabilities are evident in its migration, often crossing the Gulf of Mexico and the Caribean.

(Semenchuk, 1992; Kaufman, 1996)

Length: 22 cm

The sora occupies a freshwater wetland habitat throughout its range; it also uses salt marshes while overwintering. The preferred habitat provides considerable cover for breeding soras, and consists mostly of freshwater wetlands with stands of cattail, sedges, and other tall wetland plants (Kaufman, 1996).

More info for the terms: avoidance, cover, density, marsh

Water and emergent vegetation are important sora habitat characteristics.

Water: Soras use areas with a wide range of water depths. They are often observed in water less than 1 foot (30 cm) deep [24,38,50,54], although the average water depth of sora heavy-use areas in Arizona was 20 inches (52.2 cm) [8]. In northwestern Iowa, average water depth in sora territories was 15 inches (38.4 cm), which was significantly (p<0.025) more shallow than water depths at random locations in the marsh [27]. Sora nesting sites occurred in shallower water than random sites in western New York [34]. Average water depths reported at nest sites range from 4 inches (10.7 cm) for 4 sora nests in Colorado [23] to nearly 10 inches (24.2 cm) for sora nests in western New York [34]. In areas of deep water, soras typically wade on mats of floating vegetation [23,26].

Water level fluctuations may result in nest abandonment. For example, at a site in Colorado where water level increased more than 8 inches (20 cm), a sora nest with 7 eggs was abandoned [24]. In Alberta, soras nested in more vegetation types during a drought year, most likely due to substantially reduced water levels in the vegetation used the previous year [36].

Soras use areas with shallower water in fall than in spring [8,50,54]. It is likely that these seasonal differences reflect variation in availability of different habitats rather than habitat preference changing seasonally [54]. The mean water depths of sora locations in northeastern Missouri during spring and fall are shown in the table below [50].

Mean water depth in mm (range) Spring (n=60) 181 (27-433) Fall (n=68) 148 (54-301)

Soras typically avoid open water. There is a significant (p≤0.05) negative relationship between area of open water and sora use of wetlands in Maine [19] and sora relative abundance in Saskatchewan [57]. In western New York, sora nesting sites had a lower percentage of open water than random sites [34], and in Arizona soras used open water areas less than their availability [8].

Emergent vegetation: Sora nesting sites had larger percentage of emergent vegetation than random sites in marshes of western New York [34]. Sora numbers in wetlands of northeastern North Dakota were significantly (p<0.05) positively correlated (r=0.45) with hectares of live emergent vegetation [32]. In east and central Maine, wetlands used by soras had significantly (p=0.01) greater area of emergent vegetation than unused wetlands [19].

Density of emergent vegetation in sora habitat varies. Reported density of emergent vegetation ranges from an average of 121.9 stems/m² in sora territories in northwestern Iowa [27] to 333 stems/m² on sites in northeastern Missouri used during fall migration [50]. In western New York, cover was greater than 70% at 95% of sora nests. In addition, nesting sites had more horizontal cover at 20 inches (0.5 m) above water level than random sites [34]. However, average stem density on sora territories was not significantly (p>0.05) different from random sites in northwestern Iowa [27].

Height of emergent vegetation in sora habitat also varies. Height of vegetation reported in the literature ranged from 8 to 11 inches (20-30 cm) in the spring after a winter disturbance in northwestern Iowa [27] to 84 inches (213 cm) in areas heavily used by soras in Arizona [8]. In marshes of western New York, average vegetation height at sora nesting sites was shorter than at random locations [34]. However, the average height of emergent vegetation in sora territories in northeastern Iowa was not significantly (p>0.05) different from the height of vegetation in random plots [27].

In Arizona, both cover and height of vegetation used by soras varied with seasons. Conway suggested the differences likely reflected the varied diet of the sora [8]. The availability of habitat in different seasons is another possible source of seasonal differences in sora habitat [54].

Extent of woody vegetation surrounding South Dakota wetlands was not significantly (p=0.6) associated with sora occurrence [45]. However, in marshes of western New York, there was a significant (p=0.041) negative relationship between percent flooded timber on a site and sora relative abundance [34].

Soras may prefer some cover types. In Arizona, 65.3% of sora use was in southern cattail (Typha domingensis), although it comprised only 16.5% of the vegetation. Bulrushes and a mixed-shrub community were also used more than their availability, while saltcedar (Tamarix chinensis) and arrowweed (Pluchea sericea) were avoided [8]. A literature review notes sora avoidance of purple loosestrife (Lythrum salicaria)-dominated sites [6]. In east and central Maine, wetlands used by soras had significantly (p=0.05) more ericaceous vegetation, such as leatherleaves (Chamaedaphne spp.), sweetgales (Myrica spp.), and laurels (Kalmia spp.) [19]. In marshes of northwestern Iowa, broadleaf arrowhead (Sagittaria latifolia) occurred in sora territories significantly (p<0.01) more often than at random sites. Johnson and Dinsmore [27] imply that this likely results from both species preferring similar site conditions. In May and June in Wisconsin, soras were detected significantly (p<0.025) more often in cattail (Typha spp.) survey areas than in sedge areas [51]. However, in southeastern Wisconsin during the breeding season, there was no significant (p=0.943) difference in sora densities between habitats comprised predominantly of cattail, sedge, or bulrush [38]. In addition, soras' use of glaucous cattail (Typha × glauca), broadfruit bur-reed (Sparganium eurycarpum), sedge, river bulrush (Schoenoplectus fluviatilis), and hardstem bulrush (S. acutus var. acutus) habitats in marshes of northwestern Iowa generally reflected availability of these habitats [27].

Seasonal differences in sora habitat use have been reported. In northeastern Missouri in spring, the likelihood of detecting sora in robust emergents, such as cattail (Typha spp.) and longroot smartweed (Polygonum amphibium var. emersum), was over 6 times that of detecting soras in these areas in fall. However, availability of habitats during various times of the year was not addressed [50]. In a study performed in southeastern Missouri, plant species used by sora during spring and fall migration differed significantly (p=0.005). However, the author qualifies this finding with his observation of major seasonal differences in vegetation availability [54].

Temperature: Temperature may also influence sora abundance. In Colorado, average April temperature was significantly (p<0.01) negatively correlated (r= -0.94) with sora abundance. On sites that had average April temperatures ≤42 °F (5.6 °C), soras were more abundant than closely related Virginia rails (Rallus limicola), while on warmer sites the sora to Virginia rail ratio declined [24].

Densities: Sora densities reported in literature reviews vary from to 12 soras/acre in Colorado [12] to 0.47 pair/ha in Indiana [42]. An average of 1.3 soras/ha responded to calls across sites in Colorado [24]. A similar density of soras was found in southeastern Wisconsin [38]. In Iowa, average density over 2 years and several marsh habitats was 1.3 pairs/ha [27].

Effects of spatial arrangement/area: Landscape factors, such as marsh area, habitat edges within marshes, and the number of marshes in a region may influence soras.

Although soras occur in marshes of all sizes, they may occur at higher densities in intermediate-sized marshes. Soras were significantly (p≤0.01) positively related with total wetland area and perimeter area of surface water in east and central Maine [19] and were significantly (p<0.05) positively related to area of wetlands in Saskatchewan [57]. In Maine, soras used 10% of 2.5-acre (1 ha) wetlands, 40% to 50% of wetlands from 2.5 to 50 acres (1-20 ha) in size, and 20% of wetlands larger than 50 acres (20 ha). [19]. In western New York, soras were significantly (p=0.007) more abundant in marshes from 100 to 250 acres (41-100 ha) in size than in smaller (<100 acres (41 ha)) or larger (250-380 acres (101-155 ha)) marshes. In addition, sora nests were detected more often in the 100- to 250-acre (41-100 ha) marshes [34].

Soras also seem to prefer edge habitats. Breeding sora density was significantly (p<0.001) correlated (r=0.62) with the perimeter:area ratio of northwestern Iowa marshes. The distance from the center of sora territories to a habitat edge was also significantly (p<0.005) less than from the center of Virginia rail territories [27]. In Arizona, habitat edges were closer to sora heavy use areas than random sites [8].

Wetland dynamics at a large scale can affect soras. Indices of sora population at 3 "levels of response" were significantly (p<0.01) correlated (r≥0.70) with the number of ponds present in the prairie pothole region of North Dakota in May [47].

More info for the terms: marsh, shrub

Soras are commonly reported in plant communities dominated by the species listed below:

Cattails (Typha spp.) [8,24,28,34,36,38,51]
Sedges (Carex spp.) [24,27,36,38,51,54]
Bulrushes (Scirpus spp.) [8,24,27,38,40]
Smartweeds (Polygonum spp.) [36,40,54]
Rushes (Juncus spp.) [36,54]
Rice cutgrass (Leersia oryzoides) [40,50]
Barnyard grasses (Echinochloa spp.) [50,54]

Although soras use wetland and marsh habitats almost exclusively throughout the year, they may be found in other habitats.

Outside of wetlands, soras are most often reported in cultivated areas during migration or in the postbreeding period. For instance, a sora was observed 3 miles (5 km) from marshland in a cultivated field in Iowa in the middle of August [25]. A male sora was observed less than 1,000 feet (300 m) from a large wetland in a soybean (Glycine max) field in northwestern Iowa during the postbreeding period [26]. From early June to mid-July, soras were observed on farms in Saskatchewan sown mainly with wheat (Triticum aestivum) [57]. In addition, Ribic [51] cites 2 sources for the occurrence of soras in cranberry (Vaccinium macrocarpon) bogs.

Soras have also been reported in flooded wooded areas [19,34]. In western New York, soras occurred during the breeding season on a study site where 26% of the area was categorized as "flooded timber," and 5% was classed as "scrub/shrub marsh" [34]. In eastern and central Maine, an average of 2.1 soras was observed in wooded swamps per 100 hours of observation during the breeding season [19]. On a nonbreeding (August-April) site in southwestern Arizona, soras were found to use a "mixed shrub community" more than expected based on its availability [8]. Species composition of these areas was not described.

Soras were observed at low abundances on a site with Douglas-fir (Pseudotsuga menziesii), ponderosa pine (Pinus ponderosa), and trembling aspen (Populus tremuloides) in British Columbia. Details regarding the circumstances of these observations, such as distance to the nearest wetland or the degree of attachment to this site, were not included [41].

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This species is known to occur in association with the following Rangeland Cover Types (as classified by the Society for Range Management, SRM):

More info for the terms: fresh, marsh

SRM (RANGELAND)COVER TYPES [56]:

216 Montane meadows

217 Wetlands

422 Riparian

726 Cordgrass

806 Gulf Coast salt marsh

807 Gulf Coast fresh marsh

818 Florida salt marsh

819 Freshwater marsh and ponds

822 Slough

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

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SAF COVER TYPES [15]:

None

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

KUCHLER [29] PLANT ASSOCIATIONS:

K049 Tule marshes

K073 Northern cordgrass prairie

K078 Southern cordgrass prairie

K079 Palmetto prairie

K080 Marl everglades

K092 Everglades

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

ECOSYSTEMS [18]:

FRES37 Mountain meadows

FRES41 Wet grasslands

Systems

• Terrestrial
• Freshwater

The sora occupies a freshwater wetland habitat throughout its range; it also uses salt marshes while overwintering. The preferred habitat provides considerable cover for breeding soras, and consists mostly of freshwater wetlands with stands of cattail, sedges, and other tall wetland plants (Kaufman, 1996).

Comments: Primarily shallow freshwater emergent wetlands (e.g., marshes of cattail, sedge, blue-joint, or bulrush), less frequently in bogs, fens, wet meadows, and flooded fields, sometimes foraging on open mudflats adjacent to marshy habitat. Also occurs locally in swamps, along slough borders, and in mangroves. Can use very small marshes (e.g., 4 nests have been found in a half-acre marsh) (see Brewer et al. 1991). Nonbreeding: also in coastal salt marshes; roosts in cattails or other dense vegetation. In northern wetlands and midle-southern Atlantic coastal wetlands, wild rice provides habitat during migration (Fannucchi et al. 1986).

Nests about 15 cm above water level in marsh vegetation, often near open water. Nest is anchored to emergent plants or sometimes placed on top of a mound (Cogswell 1977). In Michigan, nests most often were over water 10-15 cm deep (see Brewer et al. 1991).

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

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

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

Arrives in northern breeding areas April-May, departs by September-October (Bent 1926). May make local migrations in Pacific states, generally extensive migrations elswhere. Migrants arrive in Costa Rica mostly in October, depart by late February or March (Stiles and Skutch 1989). Migration flights are mostly at night (Cogswell 1977).

Diet consists mainly of seeds, insects and snails. Seeds are obtained from sedges (Carex spp.), grasses (Calamagrostis spp., Bromus spp., Scoacloa spp., Poa spp., etc) or other wetland plants. Snails and insects are picked from ground surface, or by probing soft mud and vegetation with its bill.

(Kaufman, 1996)

Soras eat a wide range of foods. Animals that are commonly reported as sora food items include snails (Gastropoda), crustaceans (Crustacea), spiders (Araneae), and insects (Insecta), mainly beetles (Coleoptera), grasshoppers (Orthoptera), flies (Diptera), and dragonflies (Odonata) [25,39,40,53]. Soras often eat the seeds of plants, such as smartweeds, bulrushes, sedges, and barnyard grasses [2,25,39,40,53]. Seeds of annual wildrice (Zizania aquatica) and rice cutgrass are eaten by soras in the eastern United States [39,40]. A literature review lists crowngrass (Paspalum spp.) and rice (Oryza sativa) as relatively important food sources for soras in the Southeast. Plants comprising <5% of the sora's diet are also listed and include spikerushes (Eleocharis spp.), duckweeds (Lemnaceae), pondweeds (Potamogeton spp.), panicgrasses (Panicum spp.), cordgrasses (Spartina spp.), and saltgrass (Distichlis spicata) [39].

According to a literature review, soras eat more plant food in fall and winter (68%-69%) than in spring and summer (40%) [39]. Plant material such as hairy crabgrass (Digitaria sanguinalis), fall panicgrass (Panicum dichotomiflorum), and bristlegrass (Setaria spp.) occurred at substantially higher frequencies and in much larger volumes in sora esophagi collected in southeastern Missouri during fall migration than those collected in spring. In addition, animals comprised a larger volume of the spring diet than the fall diet. The volume of animal material in esophagi collected in spring was predominantly composed of adult beetles and snails from the Physidae family [53].

Diet consists mainly of seeds, insects and snails. Seeds are obtained from sedges (Carex spp.), grasses (Calamagrostis spp., Bromus spp., Scoacloa spp., Poa spp., etc) or other wetland plants. Snails and insects are picked from ground surface, or by probing soft mud and vegetation with its bill.

(Kaufman, 1996)

Comments: Eats mollusks, insects, seeds of marsh plants, duckweed (Terres 1980). Seeds, especially those of sedge and bulrush, may comprise the bulk of the diet. Often forages along edges (e.g., between vegetation types or along the edge of open water).

Sora eggs are eaten by several species including American minks (Mustela vison), skunks (Mephitidae), coyotes (Canis latrans), grackles (Quiscalus spp.), crows (Corvus spp.), and herons (Ardeidae) [2,14,36]. Predation of adult soras by American minks, coyotes and peregrine falcons (Falco peregrinus) has been reported [14,36,46].

More info for the terms: cover, fire severity, frequency, litter, marsh, peat, prescribed burn, severity, succession, swamp, wildfire

Very little information is available on the effects of fire on soras. The available information is limited in several respects including temporal and spatial scale. There is also a lack of information regarding the effects of various site and fire characteristics on soras' response to burning. In addition, as of 2006 there were no comparisons of sora demographic data from burned and unburned areas.

Soras may leave burned areas soon after fire. Within 4 days of a prescribed burn on the coastal prairie of Texas, a sora left the area, possibly due to unsuitable habitat [22]. Immediately after patchy prescribed burns in Florida, black rails were observed in unburned areas [31]. In addition, a review states that the lack of cover available after fire results in rails leaving burned areas [7].

Soras have been reported in recently burned areas. For instance, 2 soras were observed on the shoreline of a man-made pond in northern Florida within 5 months of a winter prescribed burn. Soras were not observed in the unburned portion of the shoreline [61]. On a Colorado site where 90% of the area had been burned under prescription in previous winters, a large number of rails, most likely Virginia rails and soras, was observed during spring migration in remaining and new (<12 inches (30 cm)) narrow-leaved cattail (Typha angustifolia) vegetation [23].

There is limited evidence that soras may not be greatly affected by fire. In a study on Matagorda Island, Texas, members of the Rallidae family did not exhibit significant (p>0.24) responses to winter or summer prescribed burns either 6 to 10 months or 18 to 22 months after fire [60]. In the Chenier Plain in southwestern Louisiana, winter prescribed burning in habitats of varying management history and salinity did not have substantial effects on soras. The following table shows the average number of soras detected per survey in each of the habitats in the 3 springs (April-June) following treatment [17]

Year

Burned

Unburned

Impounded Not impounded Impounded Not impounded Brackish Intermediate Brackish Saline Brackish Intermediate Brackish Saline 1996 0.1 0.0 0.1 0.2 0.0 0.0 0.1 0.1 1997 0.0 0.1 0.1 0.0 0.0 0.1 0.1 0.0 1998 0.0 0.1 0.2 0.0 0.1 0.2 0.1 0.1

Since emergent vegetation provides cover and food for soras, the response this vegetation has to fire is likely to have a large influence on the effect a fire will have on soras. Wetlands typically recover quickly after fire. A review summarizes a report of vegetation in a Florida freshwater marsh nearing complete recovery 6 months after prescribed burning [62]. Vegetation structure on a site in southwestern Louisiana returned to prefire conditions within 1 year of a winter prescribed burn [17]. In Glacier National Park, Montana, sedge meadows were mostly revegetated the year following the 1988 Red Bench Wildfire [63]. In South Dakota, screening cover 1 growing season after spring prescribed burns was not significantly (p>0.05) different from cover before the treatment [55]. On a burned shoreline in Florida, frequency of maidencane (Panicum hemitomon) and swamp smartweed (Polygonum hydropiperoides) was similar on burned and unburned sites the May following a winter prescribed burn. In addition, burning resulted in higher productivity of the wet-prairie vegetation [61].

Somewhat longer recovery times have been reported. In cordgrass/crowngrass habitat on Matagorda Island, vegetation attributes recovered to prefire levels by 18 to 22 months after spring and fall prescribed burns [60]. After a wildfire in a Texas tidal flat, community structure did not recover for 16 months, vegetative cover did not met or exceed prefire cover for 19 months, and live and litter biomass had not reached prefire levels by postfire month 26 [33].

The response of marsh vegetation to fire is influenced by several factors including fire characteristics such as severity and season of burning, and site conditions such as salinity and hydrologic factors.

High-severity fires that burn into the organic layer are likely to result in long recovery times. Areas of sedge meadows of Glacier National Park where the peat had been completely consumed in the Red Bench Wildfire recovered more slowly than areas where rhizomes and roots had survived [63]. Rhizomatous plant species are likely to survive fires that do not burn deep into the organic ground layer, resulting in quick recovery of vegetation after fire [17,63]. A review summarizes the effect of fire severity on marshes, including references to severe fires consuming peat and resulting in long vegetation recovery times and the creation of open water [48].

Season of burn can affect the response of marsh vegetation to fire. There was no significant (p>0.05) difference in screening cover a growing season after spring prescribed burning in a narrow-leaved- and common cattail (Typha latifolia)-dominated wetland of South Dakota. However, sites that were burned in fall had significantly (p<0.05) less cover 1 growing season after fire than before the burn [55].

Site characteristics also influence vegetation response to fire. Results of a study on a marsh in Florida suggest that fire can have variable effects that are related to hydrology and nutrients [30]. Researchers investigating prescribed fires in southwest Louisiana note the probable influence of several site factors such as plant community composition before the burn, water depth, and salinity [17]. A review summarized the role of salinity and other preexisting site conditions on postfire succession in eastern marshes [62].

Fire ecology: According to a review, wetlands tend to burn during drought, and small wetlands and marshes can burn at frequencies similar to adjacent vegetation [11]. For information regarding presettlement FIRE REGIMES of marshes, peatlands, and swamps of the southeast see [16]. A review discusses succession in eastern marshes [62].

The following table provides fire return intervals for plant communities and ecosystems where sora is important. For further information, see the FEIS review of the dominant species listed below.

Community or ecosystem Dominant species Fire return interval range (years) bluestem-Sacahuista prairie Andropogon littoralis-Spartina spartinae <10 northern cordgrass prairie Distichlis spicata-Spartina spp. 1-3 [49] Everglades Mariscus jamaicensis <10 [43] mountain grasslands Pseudoroegneria spicata 3-40 (x=10) [3,4] tule marshes Scirpus and/or Typha spp. <35 southern cordgrass prairie Spartina alterniflora 1-3 [49]

More info for the terms: fire severity, frequency, severity

Soras may be more vulnerable to direct fire impacts than many birds. In addition to their terrestrial habits, adult sora are flightless for a period after breeding while they molt [2]. However, 2 prescribed fires in the coastal prairie of Texas during February and March did not result in any rail (Rallidae) mortality. Rails, including soras, were thought to have survived by seeking shelter under damp vegetation. The authors suggest burning later in the spring or in the summer, when amounts of standing water are reduced, could lead to a larger direct impact [22]. See the Research Paper by Grace and others [22] for details of this study. In addition to season, the scale of burning can also influence rail survival. Patchy prescribed burns in Florida in August left many 0.1- to 2-acre (0.04-0.8 ha) unburned areas, where black rails (Laterallus jamaicensis) were observed immediately after burning. In contrast, widespread prescribed fires that burned 90% of 2,400 acres (970 ha) in January resulted in direct bird mortality, possibly due to burning of the areas birds used for shelter. The authors strongly encourage the incorporation of wildlife escape areas into burning plans [31].

Although there were no data directly investigating sora nest mortality due to fire as of 2006, literature reviews have used fire characteristics and life history of species to speculate on possible effects of fire on nesting success and bird populations [37,52]. Since soras nest on the ground, even low-severity fires could have negative impacts on eggs and nestlings. Young nestlings are less mobile than adults [28], which could limit their options when seeking shelter from fire. The possibility of sora renesting may reduce the direct effects of a fire on sora recruitment [37,52]. Nests impacted early enough in the breeding season could be compensated for by later nesting attempts. However, since soras typically rear only 1 brood per year (see Timing of Major Life History Events), fires in the mid- to late-breeding season may have a larger detrimental effect on sora recruitment. In addition to the timing and uniformity of the burn, other fire characteristics such as the fire severity and frequency are likely to influence the degree to which fire directly impacts sora reproduction [37].

Despite the lack of direct impact of fire on rails during prescribed fires in the coastal prairie of Texas, indirect mortality of Virginia rails and yellow rails (Coturnicops noveboracensis) due to fire-related predation was observed [22].

Migration: Soras' northern migration occurs in spring, primarily in April and May. For instance, in east-central Kansas significantly (p<0.05) more soras were detected from 24 April to 7 May than the 2-week periods before or after [64]. In southeast Missouri, soras were observed from 25 March to 6 May [54]. Soras were 1st detected in April to early May in Colorado [24], Iowa, and Minnesota [28]. In a summary of the 1st detections of soras in Minnesota, Manitoba, and Saskatchewan, all occurred in April [46].

Soras depart their breeding grounds as early as July and as late as October. Soras were observed returning to wintering grounds in Arizona as early as late July [8]. Although local movements may obscure migration occurring in July, most migration occurred in August and September in Colorado [23]. In northern Ohio, sora abundance was increased in late August and September by migrating individuals [2]. In southeastern Missouri, soras were observed from 5 September to 27 October [54]. Soras have been observed in Manitoba and Saskatchewan as late as October [46].

Nesting: Although sora nesting activities have been observed from late April through early August, the peak nesting period typically occurs from May to early July. In New York, nesting was initiated in late April [34]. A nest search and literature review study of soras in Colorado reports a clutch initiated in early August. However, mean clutch initiation dates occurred in May and June in regions across the state [12]. Studies from northern Ohio [2], North Dakota [59], and Alberta [36] report nesting from May to July. In a review, sora nests with eggs were recorded from early May to early July in Indiana [42].

Sora females begin construction of saucer-shaped nests on the ground or on a platform over shallow water at the start of egg laying [12,34]. According to literature reviews, clutch sizes typically range from 8 to 13 eggs [12,42], although clutch sizes of up to 16 have been reported [12,28,36]. Both parents incubate the eggs. Incubation lasts approximately 19 days, although a wide range of incubation periods has been reported in the literature [36]. Eggs hatch over a span of 2 to 13 days [28]. Nestlings are precocial and are capable of walking and swimming short distances (<3 feet (1 m)) by the end of their 1st day. Young soras are independent by about 4 weeks of age [12,26]. According to a literature review, soras brood once per season [12]. Some late broods may be 2nd nesting attempts, but there is only 1 report in the literature of a 2nd brood attempt after a successful nest [36]. For information on breeding behavior of soras, see [28]. For information on conspecific nest parasitism and egg discrimination in soras see [58].

Sora nest success rates vary across locations and years. In summaries of the literature addressing sora apparent nest success, reported proportions of successful nests varied from 0.61 in Michigan to 0.833 in Minnesota [2,9]. In western New York, the nest success rate of 6 sora nests was 0.43, and the daily nest success rate was 0.97 [34]. Using data from the Cornell Laboratory of Ornithology's nest record program, nesting success rate of soras in North America was estimated as 0.529 over a 28-day period (n=108) [9]. On a site in Alberta, 80.6% of eggs successfully hatched, while the following year only 59.6% of eggs hatched. The authors conclude that diminished water level interacting with predators and trampling by cattle resulted in decreased hatching success [36].

During late summer, soras are flightless for a period during their post-nuptial molt [2].

Home Range: Sora home range size varies. Sora brood-rearing home ranges in northwestern Iowa averaged 0.5 acre (0.19 ha) [26]. In Arizona, sora home range size varied from 1.5 acres (0.59 ha) in the early breeding season to over 2 acres (0.91) ha in the postbreeding season. These seasonal differences in sora home range size were not significant (p>0.05) [8].

Survival: Few data are available on the survival of soras. Radio-marked soras in Arizona had a nonbreeding survival probability of 0.308. The authors suggest the low survival rate may be due to increased mortality of radio-marked birds [9]. Likely causes of mortality are predation (see Predators) and human-caused sources such as road kill [2].

BREEDING: Home range size averaged 0.19 ha during brood-rearing (Johnson and Dinsmore 1985). NON-BREEDING: Roosts communally. Home range averaged 0.78 hectares in Arizona during winter (Conway 1990).

Comments: Leaves dense cover mostly in early morning and evening.

Nests are woven into a shallow basket from dead emergent wetland vegetation, and attached to stalks of dense, live vegetation. Nests are generally placed over or adjacent to water, occasionally occurring in dry environments such as willows or grassy habitat near water's edge. (Godfrey, 1986).

The average clutch size ranges from 10-12 (sometimes 6-18) brown, spotted eggs, occasionally laid in two layers to accommodate such large numbers in a relatively small nest. Incubation by both parents lasts from 18-20 days, and is initiated with the laying of the first few eggs (Kaufman, 1996).

Young hatch asynchronously due to incremental stages of incubation. Precocial downy young may be cared for by one parent, as the other parent incubates remaining eggs. Young soras leave the nest shortly after hatching, and mainly forage themselves, having been taught by a parent (Salt and Salt, 1976). At 21-25 days young soras fledge and gain independence from their parents' care.

(Kaufman, 1996)

Nests are woven into a shallow basket from dead emergent wetland vegetation, and attached to stalks of dense, live vegetation. Nests are generally placed over or adjacent to water, occasionally occurring in dry environments such as willows or grassy habitat near water's edge. (Godfrey, 1986).

The average clutch size ranges from 10-12 (sometimes 6-18) brown, spotted eggs, occasionally laid in two layers to accommodate such large numbers in a relatively small nest. Incubation by both parents lasts from 18-20 days, and is initiated with the laying of the first few eggs (Kaufman, 1996).

Young hatch asynchronously due to incremental stages of incubation. Precocial downy young may be cared for by one parent, as the other parent incubates remaining eggs. Young soras leave the nest shortly after hatching, and mainly forage themselves, having been taught by a parent (Salt and Salt, 1976). At 21-25 days young soras fledge and gain independence from their parents' care.

(Kaufman, 1996)

Clutch size is 6-18 (commonly 10-12). Incubation, by both sexes, lasts 18-20 days. In the upper Midwest, most hatch in late May or early June. Young are tended by both parents, leave nest within 1-2 days but may return at night for brooding. Cornell Nest Record Program data indicate a nest success rate of 0.53 (Conway et al. 1994). Females may lay eggs in the nests of conspecifics; females may be able to recognize eggs that are not their own (see Sorenson 1995, Condor 97:819-821).

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There are 4 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 4
Specimens with Barcodes: 5
Species With Barcodes: 1

Numbers have declined across the sora's range, coinciding with loss of wetland habitat, however the species is still abundant (Kaufman, 1996). The sora is an unprotected species, and is considered to be a migratory game bird (U. S. Fish and Wildlife Service, 2000), although it is not often hunted.

IUCN Red List of Threatened Species: least concern

US Migratory Bird Act: protected

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

Information on state-level protected status of animals in the United States is available at NatureServe, although recent changes in status may not be included.

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Justification

History

• 2008
  Least Concern
• 2004
  Least Concern

Numbers have declined across the sora's range, coinciding with loss of wetland habitat, however the species is still abundant (Kaufman, 1996). The sora is an unprotected species, and is considered to be a migratory game bird (U. S. Fish and Wildlife Service, 2000), although it is not often hunted.

US Migratory Bird Act: protected

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5B - Secure

United States

Rounded National Status Rank: N5B,N5N : N5B: Secure - Breeding, N5N: Secure - Nonbreeding

Rounded Global Status Rank: G5 - Secure

Comments: Harvest of wild and planted rice may result in nest destruction and excessive disturbance (Fannucchi et al. 1986).

There is a large amount of uncertainty regarding soras' response to fire, and much more data are need to make detailed recommendations. The data currently available suggest that low-severity fires, performed when soras are not present on a site and at frequencies that allow emergent vegetation to recover, will likely have the least negative impact on soras. Incorporation of escape areas into burning plans [31] will likely minimize direct impacts of fires on soras when they are present on a site. Patchy burns may have long-term benefits as well, given the possible preference of soras for edge habitats (see Effects of spatial arrangement/area). In addition to fire characteristics, site conditions that influence vegetation recovery, such as hydrology and species composition, may impact soras' response.

Sora populations in the United States have been declining. Breeding bird survey data show a 3.3% annual decline in sora populations from 1966 to 1991. Although populations in Canada were stable from 1982 to 1991, sora populations in the United States declined significantly (p<0.01) during the same period, at an average rate of 8.5% annually. Population declines in central North America were the most severe [9]. Reviews also note sora declines [12,50].

Use of playback calls has been shown to increase detection of soras [20,34,51]. Use of playback calls in developing monitoring programs for soras has been investigated by [21,35,38].

Grazing is likely to negatively impact sora habitat. In southeastern Oregon, sora did not occur on a site where grazing was recently (0-2 years) excluded, but did occur on a nearby site where grazing had been excluded for 30 years. Soras occurred after 3 years of no grazing on the previous site [13]. Management recommendations based on expert opinion suggest that sora be considered when developing a grazing plan, as grazing consistently has a negative impact on wetland habitats [65].

Management Requirements: Eddleman et al. (1988) provided the following information on managing waterfowl areas in a way that is compatible with the conservation of inland rails. Wetlands of the greatest importance to rallids (other than gallinules and coots) are shallower and have greater percentage cover by emergent vegetation than those typically managed for waterfowl. Dewatering in northern breeding areas should occur before April 15 to avoid disruption of rail nest initiation. Gradual dewatering (and presumably presence of topographic diversity) provides the maximum amount of favorable foraging area (edge between moist soil and marsh). Amount of nesting cover (emergent perennial vegetation) should be maximized. To provide rail habitat every year, different impoundments should be flooded in different years.

For autumn migration, shallow flooding should commence in late summer in middle latitudes (vs. late autumn or winter for waterfowl), and habitat should include various shallow water depths, robust cover, and short-stemmed seed-producing plants. Flooding too deeply and too early, and deep winter flooding, lead to loss of robust plant cover.

In spring, areas that have annual grasses and smartweeds should be shallowly flooded (< 15 cm), with some areas flooded to depth of up to 50 cm. Drawdowns are most favorable when they concentrate invertebrate prey. These conditions also provide excellent habitat for dabbling ducks such as blue-winged teal and northern shoveler. Land leveling, which reduces topographic diversity and favorable rail foraging habitat (edge) should be avoided.

Rice harvest should be managed in such a way as to minimize nest destruction and disturbance of soras (Eddleman et al. 1988).

The sora is considered a game bird under the Migratory bird treaty act (U.S. Fish and Wildlife Service, 2000) and may be hunted for food.

Viewing a sora in its natural habitat is a well won prize for an avid birder's effort.

The sora is considered a game bird under the Migratory bird treaty act (U.S. Fish and Wildlife Service, 2000) and may be hunted for food.

Viewing a sora in its natural habitat is a well won prize for an avid birder's effort.