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Effects of Management Practices on Wetland Birds:

Sora

Drawing by Patsy Renz: Sora

This report is one in a series of literature syntheses on North American wetland birds. The need for these reports was identified by the Prairie Pothole Joint Venture (PPJV), a part of the North American Waterfowl Management Plan. The PPJV adopted a goal to stabilize or increase populations of declining grassland- and wetland-associated wildlife species in the Prairie Pothole Region. To further that objective, it is essential to understand the habitat needs of birds other than waterfowl, and how management practices affect their habitats. The focus of these reports is on management of breeding habitat, particularly in the northern Great Plains.

This resource is based on the following source:

Zimmerman, A. L., B. E. Jamison, J. A. Dechant, D. H. Johnson, C. M. Goldade, J. O. Church, and B. R. Euliss.  2003.  Effects of management practices on wetland birds: Sora.  Northern Prairie Wildlife Research Center, Jamestown, ND.  31 pages.

This resource should be cited as:

Zimmerman, A. L., B. E. Jamison, J. A. Dechant, D. H. Johnson, C. M. Goldade, J. O. Church, and B. R. Euliss.  2003.  Effects of management practices on wetland birds: Sora.  Northern Prairie Wildlife Research Center, Jamestown, ND.  Northern Prairie Wildlife Research Center Online.  http://www.npwrc.usgs.gov/resource/literatr/wetbird/sora/sora.htm (Version 12MAY2003).


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Effects of Management Practices on Wetland Birds:

Sora

Amy L. Zimmerman, Brent E. Jamison, Jill A. Dechant, Douglas H. Johnson,
Christopher M. Goldade, James O. Church, and Betty R. Euliss

Series Coordinator: Douglas H. Johnson
Series Assistant Coordinator: Jill A. Dechant

Reviewer: Scott Melvin

Range Map: Jeff T. Price

Illustration: Patsy Renz

Funding: Prairie Pothole Joint Venture
U.S. Fish and Wildlife Service
U.S. Geological Survey


Organization and Features of this Species Account

Information on the habitat requirements and effects of habitat management on wetland birds were summarized from information in more than 500 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although the BBS may not capture the presence of elusive waterbird species, the BBS is a standardized survey and the range maps, in many cases, represent the most consistent information available on species' distributions. Although birds frequently are observed outside the breeding range indicated, the maps are intended to show areas where managers might concentrate their attention. It may be ineffectual to manage habitat at a site for a species that rarely occurs in an area. The species account begins with a brief capsule statement, which provides the fundamental components or keys to management for the species. A section on breeding range outlines the current breeding distribution of the species in North America, including areas that could not be mapped using BBS data. The suitable habitat section describes the breeding habitat and occasionally microhabitat characteristics of the species, especially those habitats that occur in the Great Plains. Details on habitat and microhabitat requirements often provide clues to how a species will respond to a particular management practice. A table near the end of the account complements the section on suitable habitat, and lists the specific habitat characteristics for the species by individual studies. The area requirements section provides details on territory and home range sizes, minimum area requirements, and the effects of patch size, edges, and other landscape and habitat features on abundance and productivity. It may be futile to manage a small block of suitable habitat for a species that has minimum area requirements that are larger than the area being managed. The section on brood parasitism summarizes information on intra- and interspecific parasitism, host responses to parasitism, and factors that influence parasitism, such as nest concealment and host density. The impact of management depends, in part, upon a species' nesting phenology and biology. The section on breeding-season phenology and site fidelity includes details on spring arrival and fall departure for migratory populations in the Great Plains, peak breeding periods, the tendency to renest after nest failure or success, and the propensity to return to a previous breeding site. The duration and timing of breeding varies among regions and years. Species' response to management summarizes the current knowledge and major findings in the literature on the effects of different management practices on the species. The section on management recommendations complements the previous section and summarizes recommendations for habitat management provided in the literature. The literature cited contains references to published and unpublished literature on the management effects and habitat requirements of the species. This section is not meant to be a complete bibliography; a searchable, annotated bibliography of published and unpublished papers dealing with habitat needs of wetland birds and their responses to habitat management is posted on the main page under the section Searchable Bibliography.


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Sora
(Porzana carolina)
GIF - Sora range map.
Figure.  Probability of occurrence (number of years detected/number of years route was run) of Soras in the United States and southern Canada, based on Breeding Bird Survey data, 1973-1996. Map courtesy of Jeff T. Price.

Key to management is maintaining seasonal or semipermanent wetlands with water depths of 0-92 cm and with moderately dense stands of emergent vegetation interspersed with floating or submerged residual vegetation or mudflats.

Breeding Range:


Soras breed from the Yukon through the southern Northwest Territories, southeast to Nova Scotia, and south to southern New Mexico, central Texas, northern Iowa, and Delaware (National Geographic Society 1999). Breeding distribution is disjunct and localized throughout the range (See figure for the relative densities of Sora in the United States and southern Canada, based on Breeding Bird Survey data.)

Suitable habitat:


Soras breed in fresh through brackish seasonal or semipermanent wetlands with shallow (<20 cm) or intermediate (20-45 cm) water depths and with extensive stands of emergent vegetation interspersed with floating or submerged residual vegetation or mudflats (Walkinshaw 1940; Billard 1948; Stewart and Kantrud 1965; Baird 1974; Stewart 1975; Tacha 1975; Krapu and Green 1978; Weber 1978; Johnsgard 1979, 1980; Griese et al. 1980; Faanes 1981, 1982; Greenlaw and Miller 1982; Weber et al. 1982; Kantrud and Stewart 1984; Zimmerman 1984; Peterson and Cooper 1987; Gibbs et al. 1991; Melvin and Gibbs 1994, 1996; Faanes and Lingle 1995). Soras also breed in permanent wetlands, fens, wet meadows, alkali wetlands, stock ponds, dugouts, restored wetlands, salt marshes, and in emergent vegetation along the banks of streams, rivers, or lakes (Walkinshaw 1940; Boeker 1954; Parmelee et al. 1970; Stewart 1975; Weber 1978; Faanes 1981, 1982; Weber et al. 1982; Kantrud and Stewart 1984; Delphey 1991; Svedarsky 1992; Hartman 1994; Melvin and Gibbs 1994, 1996; Schreiber 1994; Faanes and Lingle 1995; Helzer 1996; Fallon 1997; Schuster 1998; Lariviere and LePage 2000; Shutler et al. 2000; Dault 2001).

Soras inhabit wetlands with water levels ranging from 0 to 92 cm deep (Mousley 1937; Walkinshaw 1940; Billard 1948; Berger 1951; Chapman 1952; Pospichal 1952, Tanner 1953; Pospichal and Marshall 1954; Tanner and Hendrickson 1954; Horak 1964; Andrews 1973; Baird 1974; Tacha 1975; Griese et al. 1980; Johnsgard 1980; Sayre and Rundle 1984; Zimmerman 1984; Johnson and Dinsmore 1986; Manci and Rusch 1988, 1989; Svedarsky 1992; Crowley 1994; Melvin and Gibbs 1994, 1996). In areas with water >20 cm deep, abundant floating residual or submerged vegetation allows movement over water (Pospichal 1952, Johnson and Dinsmore 1985, Melvin and Gibbs 1996, Vogel 1999). Soras generally avoid areas that lack standing water (Johnson 1984, Johnson and Dinsmore 1986). In Iowa, the mean water depth within Sora territories was significantly lower (38.4 cm at 957 sites within 71 Sora territories) than water depths at random sites (44.1 cm at 420 random sites) (Johnson and Dinsmore 1986).

Soras occupy wetlands primarily composed of emergent vegetation interspersed with patches of open water (Stewart and Kantrud 1965, Gibbs et al. 1991, Crowley 1994, Naugle 1997, Shutler et al. 2000, Dault 2001, Fairbairn and Dinsmore 2001, Naugle et al. 2001). Soras avoid wetlands with large expanses of open water (Weber 1978). In South Dakota, presence of Soras in semipermanent wetlands was positively related to the percent of wetland area that was vegetated and to the number of emergent plant species composing >10% of the vegetated wetland area (Naugle 1997, Naugle et al. 2001). In another South Dakota study, presence of Soras was positively related to the presence of wetlands with central expanses of open water composing >5% of the wetland area and surrounded by a peripheral band of emergent vegetation averaging ≥1.8 m in width (Weber 1978). Presence of Soras was negatively related to the presence of wetlands with >95% open water cover. In Iowa, the presence of Soras was positively related to percent emergent vegetation cover in the wetland, water depth in the emergent-vegetation zone, and to the number of plant species in the wet-meadow and emergent-vegetation zones; presence was negatively related to the proportion of the emergent-vegetation zone composed of robust-stemmed emergent vegetation (e.g., cattail [Typha spp.], bulrush [Schoenoplectus spp.]) (Dault 2001). In Iowa, Sora density was positively related to the amount of open water interspersed within stands of emergent vegetation (Fairbairn and Dinsmore 2001). In Massachusetts, Sora presence was positively related to the interspersion of emergent vegetation and open water (Crowley 1994).

Nesting occurs in a variety of robust (e.g., cattail) or fine (e.g., sedges [Carex spp.]) emergent plant species in shallow (<20 cm) or intermediate (20-45 cm) water (Chapman 1952; Tanner 1953; Tanner and Hendrickson 1956; Horak 1964; Andrews 1973; Lowther 1977; Johnsgard 1979, 1980; Manci and Rusch 1988, 1989; Svedarsky 1992; Melvin and Gibbs 1996). Dominant plants at nest sites include cattail, bulrush (Schoenoplectus spp. or Scirpus spp.), sedge, and less frequently, bur-reed (Sparganium spp.), cordgrass (Spartina spp.), common reed (Phragmites australis), spikerush (Eleocharis sp.), sweetflag (Acorus calamus), reed canary grass (Phalarus arundinacea), rush (Juncus spp.), arrowhead (Sagittaria spp.), marsh smartweed (Polygonum amphibium), hairy whitetop (Cardaria pubescens), sprangletop (Scholochloa festucacea), bluejoint (Calamagrostis canadensis), water plantain (Alisma sp.), woolgrass (Scirpus cyperinus), tall mannagrass (Glyceria grandis), or other grasses (Allen 1934; Mousley 1937; Walkinshaw 1940; Billard 1948; Berger 1951; Pospichal 1952; Tanner 1953; Pospichal and Marshall 1954; Tanner and Hendrickson 1956; Barger 1958; Lindmeier 1960; Bent 1963; Horak 1964; Kaufmann 1971, 1989; Baird 1974; Glahn 1974; Stewart 1975; Lowther 1977; Beule 1979; Knapton 1979; Greenlaw and Miller 1982; Svedarsky 1992; Melvin and Gibbs 1994, 1996). Water depth at nest sites ranges from 2 to 58 cm (Mousley 1937; Walkinshaw 1940; Billard 1948; Berger 1951; Chapman 1952; Pospichal 1952; Tanner 1953; Pospichal and Marshall 1954; Tanner and Hendrickson 1956; Horak 1964; Andrews 1973; Tacha 1975; Griese 1977; Griese et al. 1980; Johnsgard 1979, 1980; Zimmerman 1984; Svedarsky 1992; Melvin and Gibbs 1996). Vegetation height at nest sites varies widely (Horak 1964, Zimmerman 1977) and appears not to be a critical component of Sora habitat as long as some overhead cover is available (Johnson 1984, Johnson and Dinsmore 1986). Nest sites typically are placed near (<15 m) the border between two vegetation types or near patches of open water (Walkinshaw 1940; Pospichal 1952; Pospichal and Marshall 1954; Andrews 1973; Glahn 1974; Melvin and Gibbs 1994, 1996).

A typical nest is a loosely woven basket of emergent vegetation that is either placed on the surface of the water or is suspended 5-30 cm above the surface of the water from stems of emergent vegetation (Gillette 1897, Mousley 1937, Nicol 1938, Walkinshaw 1940, Billard 1948, Berger 1951, Pospichal 1952, Pospichal and Marshall 1954, Bent 1963, Odom 1977, Svedarsky 1992, Melvin and Gibbs 1996). Nests commonly have an overhead canopy of emergent vegetation that provides concealment and a ramp of emergent vegetation that leads up to the nest from the surface of the water (Gillette 1897; Nicol 1938; Billard 1948; Pospichal 1952; Tanner 1953; Tanner and Hendrickson 1956; Horak 1964; Greenlaw and Miller 1982; Melvin and Gibbs 1994, 1996). Soras commonly construct multiple, inactive nests near active nests that serve as feeding and resting platforms (Pospichal 1952, Melvin and Gibbs 1996).

Soras may nest in association with Virginia Rails (Rallus limicola), King Rails (Rallus elegans), Wilson's Phalaropes (Phalaropus tricolor), Marsh Wrens (Cistothorus palustris), Swamp Sparrows (Melospiza georgiana), Red-winged Blackbirds (Agelaius phoeniceus), and Yellow-headed Blackbirds (Xanthocephalus xanthocephalus) (Walkinshaw 1940, Billard 1948, Berger 1951, Pospichal 1952, Pospichal and Marshall 1954, Glahn 1974, Johnson 1984, Melvin and Gibbs 1996).

Postbreeding and migratory movements:
During brood rearing, Soras may forage in wetland edges of the breeding wetland, as well as in upland fields, including rowcrops (Johnson 1984, Johnson and Dinsmore 1985, Melvin and Gibbs 1996). During postbreeding (typically July or August), Soras often disperse from breeding wetlands and either forage in adjacent upland habitat or gather on large wetlands prior to fall migration (Pospichal 1952, Pospichal and Marshall 1954, Smith 1955, Johnson 1984, Johnson and Dinsmore 1985). In Iowa, postbreeding Soras were found 1.5 to 4.8 km away from the breeding wetland (Johnson 1984). Concentrations of birds on large wetlands prior to fall migration may be related to declining water levels in breeding wetlands (Smith 1955, Griese 1977). Stands of cultivated or wild rice (Zizania palustris) are important habitats for brooding, postbreeding, and migrating Soras in Arkansas, Michigan, Minnesota, and South Dakota (Walkinshaw 1940, Chapman 1952, Meanley 1960, Odom 1977, Fannucchi 1983, Fannucchi et al. 1986, Melvin and Gibbs 1996).

During migration, Soras use moist-soil impoundments, permanent fresh or brackish wetlands, or oxbow lakes along rivers (Odom 1977; Rundle and Fredrickson 1981; Rundle and Sayre 1983; Sayre and Rundle 1984; Melvin and Gibbs 1994,1996; Vogel 1999). Favored migratory stop-over sites have shallow water (<15 cm), tall (>30 cm) and dense (>30 contacts using the point intercept method) emergent vegetation, stands of cultivated or wild rice, or areas of flooded annual grasses and forbs (Meanley 1960, Rundle and Fredrickson 1981; Rundle and Sayre 1983; Sayre and Rundle 1984; Melvin and Gibbs 1994, 1996, Vogel 1999). In Missouri, Soras preferred moist-soil impoundments characterized by water depths of 5-15 cm, mean vegetation height of 43 cm, and mixed stands of beggartick (Bidens spp.), late-flowering thoroughwort (Eupatorium serotinum), broomsedge bluestem (Andropogon virginicus), sedge (Carex spp., Cyperus spp.), rush, knotweed (Polygonum spp.), and annual grasses (Panicum sp., Echinochloa spp., Digitaria sp.) (Rundle and Fredrickson 1981, Rundle and Sayre 1983, Sayre and Rundle 1984). Vogel (1999) found that migrating Soras in Missouri used perennial vegetation in the spring and annual vegetation in the fall. The habitat change was likely related to diet differences between spring and fall. Invertebrates were important in spring, whereas seeds of annual grasses and knotweeds were important in fall. Migrants in Illinois used coal surface-mined wetlands with stands of common reed and deep water (0.3 to >1.2 m deep) (Horstman et al. 1998). A table near the end of the account lists the specific habitat characteristics for Soras by study.

Area requirements:


Soras occupy both small (<1 ha) and large (>20 ha; no upper limit given) wetlands (Krapu and Green 1978; Brown and Dinsmore 1986; Gibbs et al. 1991; Daub 1993; Prescott et al. 1995; Melvin and Gibbs 1994, 1996). In Iowa, frequency of occurrence of Soras was 100% in wetlands 11-20 ha in size, 50% in wetlands >20 ha in size, and 17-25% in the three smallest wetland size classes (<1, 1-4.9, and 5-10.9 ha) (Brown and Dinsmore 1986). Brood-rearing ranges of eight Soras in Iowa averaged 0.19 ha; five individual male ranges averaged 0.17 ha, and three individual female ranges averaged 0.22 ha (Johnson 1984, Johnson and Dinsmore 1985). Brood-rearing ranges generally were bounded by upland and open water.

Brood parasitism:
Virginia Rails occasionally lay eggs in Sora nests and vice versa (Miller 1928, Allen 1934, Tanner and Hendrickson 1956, Melvin and Gibbs 1994). Intraspecific brood parasitism in Soras also may occur (Sorenson 1995).

Breeding-season phenology and site fidelity:


Soras arrive on the breeding grounds from mid-March to early June and depart from late July to early December (Gillette 1897; Gibbs 1899; Cooke 1914; Allen 1934; Walkinshaw 1940; Billard 1948; Pospichal 1952; Tanner 1953; Pospichal and Marshall 1954; Tanner and Hendrickson 1956; Barger 1958; Lindmeier 1960; Bent 1963; Parmelee et al. 1970; Kaufmann 1971, 1989; Andrews 1973; Baird 1974; Tacha 1975; Griese 1977; Knapton 1979; Griese et al. 1980; Johnsgard 1980; Faanes 1981; Fannucchi 1983; Fannucchi et al. 1986; Janssen 1987; Svedarsky 1992; Melvin and Gibbs 1994, 1996; Kent and Dinsmore 1996; Vogel 1999). In North Dakota, the breeding season extends from late May to mid-August and peaks from early June to late July (Stewart 1975). In Iowa and Michigan, nesting occurs from mid-May to late June and peaks in mid-May (Walkinshaw 1940, Tanner 1953, Tanner and Hendrickson 1956). Although little evidence exists, Soras may renest after the failure of an initial nest (Allen 1934, Billard 1948, Pospichal 1952, Lindmeier 1960). Soras may raise two broods per season (Pospichal 1952; Tanner 1953; Pospichal and Marshall 1954; Lowther 1977; Melvin and Gibbs 1994, 1996). Little is known about mate or breeding-site fidelity. In Iowa, 44 Soras (adult and juvenile) were banded, but none was recaptured in successive years (Tanner 1953).

Species response to management:
Little is known about the effects of burning, mowing, or grazing on Soras. Kantrud and Stewart (1984) suggested that occasional burning or grazing were required to maintain wetland vegetation in the best condition for many avian species, including rail species. Overgrazing of wetland vegetation by livestock during dry periods, however, may eliminate emergent vegetation needed for breeding (Marshall 1952). Naugle et al. (2001) found that the presence of Soras in wetlands was negatively related to the intensity of grazing along wetland shorelines, presumably due to the reduction of emergent vegetation. Boyer and Devitt (1961) suggested fencing wetlands where appropriate to exclude livestock.

Although Soras may forage in cropland, agricultural areas are generally considered to be of little value to Soras (Rundle and Sayre 1983). In Colorado, irrigation practices that result in mid-summer drying of wetlands caused premature concentrations and movements of Soras in July and early August (Griese 1977, Griese et al. 1980). Harvesting of wild rice results in excessive disturbance to Soras (Fannucchi 1983, Fannucchi et al. 1986). Leaving unharvested areas in wild rice beds may be one way to mitigate this disturbance (Fannucchi 1983).

Conversion of wetlands to cranberry (Vaccinium macrocarpon) beds may negatively affect Soras because commercial cranberry production requires scraping away native vegetation and soils, ditching, diking, and depositing sand (to provide drainage for cranberry beds) (Jorgensen and Nauman 1993). Extensive road systems also are built to provide access for maintenance of cranberry beds. In Wisconsin, Soras occupied natural habitat within 100 m of cranberry beds, but avoided the cranberry beds themselves (Jorgensen and Nauman 1993).

Restored wetlands can provide important nesting habitat for Soras (Delphey 1991, Svedarsky 1992, VanRees-Siewert 1993, Hartman 1994, Schreiber 1994, VanRees-Siewert and Dinsmore 1996, Fallon 1997, Schuster 1998, Dault 2001). Restored wetlands were previously drained and tilled for agricultural uses (Delphey 1991, VanRees-Siewert 1993, Hartman 1994, Schreiber 1994, VanRees-Siewert and Dinsmore 1996, Schuster 1998, Dault 2001). In Iowa, Soras nested in one 2-yr-old restored wetland and were present in wetlands restored for 1-4 yr; the study did not examine restored wetlands older than 4 yr (VanRees-Siewert 1993, VanRees-Siewert and Dinsmore 1996). Dault (2001) found that Soras nested in natural wetlands and wetlands that had been restored for 4 to 6 yr prior to the study, but no Soras were found in wetlands that had been restored 8 to 12 yr prior to the study. The study did not examine restored wetlands older than 12 yr. In Iowa, the frequency of occurrence of Soras was greater in natural wetlands than in restored wetlands (Schreiber 1994, Schuster 1998).

The effects of most pesticides and contaminants on Soras are poorly studied. Thirteen months after 0.22 kg/ha dichlorodiphenyltrichloroethane (DDT) was experimentally applied to a 1.62-ha wetland, DDT residue from the fat of one Sora was 4.4 parts per million (ppm); the study specifically examined the process of bioaccumulation and did not present information on toxicity levels for Soras (Meeks 1968). Following application of glyphosate (N-[phosphonomethyl] glycine; trade name Rodeo*) herbicide to control cattails in North Dakota wetlands, Soras were more abundant in five control wetlands than in 12 treatment wetlands for two years post-treatment; Soras were not monitored beyond 2 yr post-treatment (Linz et al. 1997). Sora abundance was positively correlated with hectares of live vegetation (Linz et al. 1997). In North Dakota, two Soras were found dead in a wetland that was sprayed with toxaphene (chlorinated camphene, 67-69% chlorine) and oil at a rate of 2.3 kg/ha, but dead birds were not necropsied to determine the cause of death (Hanson 1952). Hanowski et al. (1997) studied the effects of mosquito (Culicidae) control treatments on avian density in wetlands in Minnesota. In each of three years, methoprene (isopropyl[2E,4E,7S]-11-methoxy-3.7.11-trimethyl-2,4-dodecadienoate; trade name Altosid*) was aerially applied to wetlands at a rate of 1.0-1.8 kg/ha. No differences in Sora densities were detected between control and treatment wetlands 2 yr prior to treatment and during the first year of treatment. In the second year of treatment, Sora densities were 77% higher in control wetlands than in treatment wetlands. In the third year of treatment, densities were >2.5 times higher in treatment wetlands than in control wetlands. The author suggested that the inconsistent results might have been due to annual variation in Sora abundance. In Wyoming, researchers found one Sora that showed toxic signs (specific characteristics of sick birds not given) after an irrigated wet meadow was sprayed with fenthion (dimethylO-[4-[methylthio]-M-tolyl]phosphorothioate) at a rate of 47 g/ha to control mosquitoes (DeWeese et al. 1983). Mercury levels in 45% of 11 tissue samples taken from the breast muscle of Soras in Georgia had mercury levels >0.5 ppm, the allowable limit for human consumption (Odom 1975). Mercury contamination originated from industrial sources along rivers. Mercury levels in breast muscle tissue ranged from 0.11 to 2.39 ppm and averaged 0.9 ppm. Of 13 liver samples, 69% had mercury levels >0.5 ppm. One liver contained 12.08 ppm mercury, 24 times the maximum allowable limit for human consumption (Odom 1975). Historically, lead shot has been found in the gizzards of Soras in Maryland and Missouri, and lead concentrations of up to 127 ppm have been found in bones of Soras (Artmann and Martin 1975, Stendell et al. 1980).

Soras often collide with utility wires or towers when flying low at night during migration and are susceptible to collisions with automobiles (Nauman 1927; Tordoff and Mengel 1956; Barger 1958; Kemper et al. 1966; Avery and Clement 1972; Andrews 1973; Crawford 1974; Thompson 1978; Knapton 1979; Malcolm 1982; Dinsmore et al. 1983, 1987; Hoving and Sealy 1987; Melvin and Gibbs 1996). Soras also have been found entangled in barbed wire fences, likely the result of flight collisions (Knapton 1979, Knight et al. 1980, Wolfe 1993).

Effects of purple loosestrife (Lythrum salicaria) invasion of wetlands on breeding Soras is unknown. No Soras were detected in purple loosestrife habitats in Massachusetts and Michigan, but they did occur in other emergent vegetation types within the same study areas (Crowley 1994, Whitt et al. 1999).

* References to chemical trade names does not imply endorsement of commercial products by the Federal Government.

Management Recommendations:

The management recommendations that follow are based on Soras' habitat requirements and may apply to the community of wetland bird species as a whole. Wetland loss and degradation should be avoided (Odom 1977; Weller 1978; Brown and Dinsmore 1986; Daub 1993; VanRees-Siewert 1993; Melvin and Gibbs 1994, 1996; Faanes and Lingle 1995; Naugle et al. 2001). The long-term protection of wetlands can be achieved through conservation easements and purchases of wetland basins (Holliman 1977, Odom 1977, VanRees-Siewert 1993, VanRees-Siewert and Dinsmore 1996, Weller 1999, Dault 2001). The ideal management strategy for waterbirds is to maintain wetland complexes (Kantrud and Stewart 1984, Brown and Dinsmore 1986, Fredrickson and Reid 1986, Daub 1993, Weller 1999, Dault 2001, Naugle et al. 2001). Because of variation in water levels over seasons or years, wetland complexes are more likely to have at least some wetlands in a water and plant regime favorable to a particular species, thus ensuring diverse species' representation in a geographical area (Pospichal and Marshall 1954, Weller 1999). Dynamic and ephemeral habitats, such as mudflats, sandbars, and meadows subject to flooding, also should be protected, because they provide foraging habitat for Soras (Weller 1999).

Soras prefer breeding in seasonal and semipermanent wetlands with shallow or intermediate water levels, diverse stands of both robust (e.g., cattail, bulrush) and fine (e.g., sedges) emergent vegetation interspersed with submerged vegetation within the wetland interior, and stands of seed-producing annuals (e.g., knotweed [Polygonum]) around the wetland edge (Melvin and Gibbs 1994, 1996). In wetlands with water control structures, conducting gradual drawdowns will encourage the growth of diverse stands of robust and fine emergent vegetation as well as seed-producing annuals (Johnson and Dinsmore 1986; Melvin and Gibbs 1994, 1996). Where possible, maintain water levels at a depth that maximizes the edge between moist-soil sites and shallow marsh (Johnson and Dinsmore 1986). Irregular or sloping bottoms within wetlands or impoundments also increases water-level diversity and vegetation-open water edge (Melvin and Gibbs 1994, 1996). Discourage the development of the following two cover types (Stewart and Kantrud 1971): cover type 3 (centrally located expanse of open water surrounded by a peripheral band of emergent vegetation), and cover type 4 (largely devoid of any kind of emergent cover); they provide little suitable emergent habitat (Johnson 1984). Generally, avian productivity and diversity are maximized in hemi-marsh situations (50:50 vegetation cover to water ratio), and these are optimal habitats for maximizing density of breeding rails. Griese (1977) suggested wetlands specifically managed for rails contain >60% robust emergent vegetation interspersed with small (not defined) openings or mudflats. Prevent extensive lodging of emergent vegetation stands with residual stems because this can impede Sora movement (Johnson 1984, Linz et al. 1997). Wetlands with dense stands of emergent vegetation that impede movement should be burned, disced, mowed, or plowed to set back succession and, if within a managed impoundment, should be reflooded to stimulate production of invertebrates (Johnson 1984, Kantrud and Stewart 1984).

In wetlands and impoundments with water-control structures, conduct complete drawdowns, if necessary, during the fall and winter, or prior to 15 April, and then reflood so that some water is available between 15 April and 1 August to provide migrant, breeding, and brood-rearing habitat for rails (Andrews 1973, Griese 1977, Rundle and Fredrickson 1981, Johnson 1984, Johnson and Dinsmore 1986). If possible, divide a wetland into several independently controlled units to allow for biennial drawdowns (Andrews 1973). This practice allows total drawdowns of some wetlands and the maintenance of standing water in others. Foraging habitat may be created by shallowly flooding areas of heterogeneous topography or by conducting partial drawdowns of more homogeneous human-created wetlands; both of these techniques concentrate invertebrate prey (Fredrickson and Reid 1986, Conway and Eddleman 1994, Conway 1995).

For fall migrants, manage for locally occurring grasses and knotweeds with high seed production that mature during Sora migration (Rundle and Sayre 1983). Discing followed by shallow (<15 cm) flooding reduces woody vegetation and stimulates the growth of robust annuals with high seed production (Fredrickson and Reid 1986). Fall flooding of robust emergents and perennials attracts migrating Soras and also decreases vigor of perennials, so that seed-producing annuals can become established in the spring to provide foraging habitat (Fredrickson and Reid 1986). Manage for short-stemmed plants in areas where robust emergent cover plants (e.g., cattail or bulrush) also are provided (Rundle and Sayre 1983). During spring, flood dead composites (Bidens spp., Eupatorium sp.) and grasses (Panicum sp., Echinochloa spp., Digitaria sp.) for cover (Rundle and Sayre 1983). Bulrush and sedge also should be provided as a source of food.

Wetland restoration efforts should focus on providing a diverse vegetative community that closely resembles that of natural wetlands (Dault 2001). To promote quick response of wetland vegetation, restore recently (<30 yr ago) drained wetlands or wetlands that were not effectively drained, such as those typically used for pasture or hayfields where there is less incentive to completely drain the area (Hemesath 1991, Hemesath and Dinsmore 1993). Active planting of wet-meadow species in restoration projects may be needed to attract wet-meadow nesting species such as rails and bitterns (VanRees-Siewert 1993, VanRees-Siewert and Dinsmore 1996, Dault 2001). Revegetation of restored wetlands varies with duration of drainage, past herbicide use and cropping system, effectiveness of drainage, and isolation; consider these factors when selecting restoration sites (VanRees-Siewert 1993, VanRees-Siewert and Dinsmore 1996). Dault (2001) suggested that >12 yr was needed to attain the full range of wetland bird species present on natural wetlands because species richness remained higher on natural than on restored wetlands 12 yr post-restoration. When feasible, restore wetlands within wetland complexes or those that are surrounded by numerous wetlands in the landscape (VanRees-Siewert 1993, VanRees-Siewert and Dinsmore 1996, Dault 2001). Restoring groups of wetlands of various types and sizes will provide habitat regardless of water conditions in a given year (Hemesath 1991, Hemesath and Dinsmore 1993, Dault 2001).

Avian mortality due to power line collisions can be avoided by placing utility wire lines several kilometers away from wetlands, waterfowl concentration areas, flyways, roosting areas, feeding areas, low passes, breeding areas, and especially paths between feeding and roosting or nesting areas (Thompson 1978, Malcolm 1982). Mortality due to fences can be prevented by reviewing fence construction plans and modifying plans for proposed management projects (i.e., replacing or removing dangerous fences) (Allen and Ramirez 1990). Fences placed through wetlands should be replaced or marked to make them conspicuous and to decrease the likelihood of bird/fence collisions.


Table.  Sora habitat characteristics.

Author(s) Location(s) Habitat(s) Studied* Species-specific Habitat Characteristics
Andrews 1973 Ohio Wetland Nested in a combination of crimsoneyed rosemallow (Hibiscus palustris) and bluejoint (Calamagrostis canadensis) and in a combination of sedge (Carex spp.) and bittersweet (Celastrus sp.); water depths at two nest sites were 7.6 cm and 15.2 cm, respectively; both nests were located along the border between emergent vegetation and open water
Baird 1974 Kansas Impoundment One nest was located in alkali bulrush (Scirpus maritimus) in water 2.5 cm deep; Soras were most frequently observed in alkali bulrush and in a mixture of cattail (Typha spp.) and alkali bulrush, and were observed in areas where water was 0-7.6 cm deep
Berger 1951 Michigan Wetland Occurred in an area dominated by broad-leaved cattail (Typha latifolia) and sedge interspersed with buttonbush (Cephalanthus occidentalis); water depth was 30 cm; nested in small, isolated clumps of sedge or in combinations of cattail and sedge; nests were 5-13 cm above water
Beule 1979 Wisconsin Wetland Of 27 nests, 12 were in cattail, 12 were in sedge, and three were in bur-reed (Sparganium eurycarpum); sedge habitat was selected more often than expected based on availability
Billard 1948 Connecticut Wetland Preferred wetlands with water depths of 2.5-25 cm and with muddy, unstable bottoms; occupied wetlands dominated by cattail with an understory of sedges and grasses (species not given); nests were constructed of cattail, grass, bur-reed, beaked sedge (Carex rostrata) or shallow sedge (Carex lurida); of 15 nests, six were in cattail, three were in bur-reed, two were in a mixture of sedges and cattail, two were in grass, one was in a clump of spiraea (Spiraea), and one was in a mixture of cattail, grass, and bur-reed; two nests were originally 13 and 20 cm above water (height above water for remaining nests was not given), but as a result of flooding, nests were built up to 48 cm above water
Boeker 1954 Colorado River, stream, wetland Occurred along the edge of the river in cattail and sedge, in wetlands vegetated by cattail and bulrush (Scirpus), and along meandering streams; bred in wetlands at elevations from 1800 to 2400 m
Boyer and Devitt 1961 Ontario Wetland One nest was located in a tuft of grass (species not given) 27 m from open water
Brown and Dinsmore 1986 Iowa Wetland Occurred in all wetland size classes examined (<1 ha, 1-4.9 ha, 5-10.9 ha, 11-20 ha, and >20 ha)
Chapman 1952 South Dakota Wetland Nested in sedges over water 15-20 cm deep
Crowley 1994 Massachusetts Wetland Presence was positively related to the area of cattail and to the interspersion of vegetation cover and open water; mean habitat characteristics at 34 locations were 20.4 cm water depth, 59.4% cattail, 26% fine-leaved emergents (e.g., sedges and grasses), 5.9% common reed (Phragmites australis), 3.8% scrub (not defined), 1.3% shrub, 0.9% Decodon, and 0.6% pickerelweed (Pontederia cordata)/arrowhead (Sagittaria)
Daub 1993 Manitoba Wetland Were present in all wetland size classes examined (<1 ha, 1-2.9 ha, 3-5.9 ha, and 6-20 ha)
Dault 2001 Iowa Wetland, wetland (restored) Nested in five of eight natural wetlands and two of eight wetlands restored 4 to 6 yr prior to the study; no nests were located in wetlands restored 6 to 12 yr prior to the study; the study did not examine restored wetlands older than 12 yr; occurrence was positively associated with the proportion of the wetland composed of emergent vegetation, water depth in the emergent vegetation zone, the number of dominant plant species in the wet-meadow and emergent vegetation zones, the total number of wetlands within 1500 m of the wetland center, and the area of seasonal and permanent wetlands within 1500 m of the wetland center; occurrence was negatively associated with proportion of the emergent vegetation zone composed of robust (e.g., cattail, bulrush) emergent vegetation and with the total area of temporary wetlands within 1500 m of the wetland center
Delphey 1991 Iowa Wetland, wetland (restored) Occurred in one of seven natural and one of 11 restored wetlands
Faanes 1981 Minnesota, Wisconsin Wet meadow, wetland Highest densities occurred in seasonal and semipermanent wetlands dominated by cattail, river bulrush (Schoenoplectus fluviatilis), and softstem bulrush (Schoenoplectus tabernaemontani); also used wetlands containing various species of waterlilies (Nymphaea spp.) and pickerelweed; nested in wet sedge meadows during periods of high water
Faanes 1982 North Dakota Wet meadow, wetland Associated with the dense emergent vegetation of semipermanent and permanent wetlands; pairs were infrequently encountered in wet meadows
Faanes and Lingle 1995 Nebraska River channel, wetland Occurred in dense (not defined) emergent vegetation at the periphery of wetlands or in wet sedge meadows within the river channel
Fairbairn and Dinsmore 2001 Iowa Wetland Density was positively associated with area of open water within the emergent vegetation zone
Gibbs et al. 1991 Maine Wetland Mean habitat values for occupied wetlands were 38% emergent vegetation, 27% floating or submerged vegetation, 20% open water, 12% ericaceous (Ericaceae, heath family) vegetation, 5% alder (Alnus), 3% timber, 13.7 ha wetland area, 3413 m of shoreline, 461 m to nearest wetland, 684 m to nearest road, 6.3 pH, and 39.3 Ás conductivity (percentages are individual means and do not add up to 100)
Gillette 1897 New York Wetland Nested in tall wetland grass (species not given), small bushes, or at the base of small saplings; nests in grass were typically 15-20 cm above water; nests were covered with a canopy of overhead vegetation
Glahn 1974 Colorado Wetland Nests were located in cattail and were <15 m from the interface between two vegetation cover types
Graetz et al. 1997 Wisconsin Wetland Were more common in cattail stands (5-19 individuals detected during 10 surveys) than in sedge stands (2-8 individuals), bulrush stands (2 individuals), or in stands of multiple plant species (1 individual)
Greenlaw and Miller 1982 New York Wetland Occupied areas where emergent vegetation was interspersed with open-water pools and with mudflats; nests were located in smooth cordgrass (Spartina alterniflora) or in combinations of smooth cordgrass and common reed, but were not located in areas of the wetland that were uniformly covered in smooth cordgrass; nests were placed on mud mounds and were covered with overhead vegetation
Griese et al. 1980 Colorado Impoundment, wet meadow, wetland Occupied wetlands, wet meadows associated with irrigated hayfields, and water storage impoundments; bred from 1120 to 3140 m in elevation; preferred wetlands dominated by cattail with shallow water (<15 cm deep) for breeding; water depth averaged 8.2 cm at 25 nests
Hartman 1994 Indiana Wetland, wetland (restored) Nested in natural and restored wetlands (numbers of nests not given)
Horak 1964 Iowa Wetland Of nine nests, four were located in hairy whitetop (Cardaria pubescens), two in cattail, two in sedges, and one in common reed; of nine nests, five were made of hairy whitetop, three of sedges, and one of cattail; vegetation coverage at nine nest sites averaged 45% hairy whitetop, 22% cattail, 22% sedges, and 11% phragmites; vegetation height at nine nests ranged from 46 cm (sedge) to 178 cm (common reed) and averaged 89 cm; water depth at nest sites ranged from 13 cm to 46 cm and averaged 28 cm; nests usually had a ramp of vegetation leading up to the nest rim
Johnsgard 1980 Nebraska Wetland Bred in wetlands with extensive stands of tall emergent vegetation; nests were built in water 22-30 cm deep and were well-concealed in cattails, bulrushes, or sedges
Johnson 1984, Johnson and Dinsmore 1985, Johnson and Dinsmore 1986 Iowa Wetland Occupied sites with standing water up to 92 cm deep; mean distances of 143 territory centers to the nearest physiographic features were 30 m to open water, 23.5 m to an interface between two vegetation cover types, 19.6 m to upland, and 18.3 m to a cattail stand; mean distance from the center of 143 territories to an interface between two vegetation cover types was significantly less (23.5 m) than 100 random points (38.2 m); breeding density was positively correlated with the ratio of shoreline length to wetland area; in the first year of the study, mean percent coverages of emergent vegetation for 223 occupied sites were 49% cattail, 30% bur-reed, 9% sedges, 7% miscellaneous, 4% river bulrush, and 1% hardstem bulrush (Schoenoplectus acutus); in the second year of study, mean percent coverages of emergent vegetation for 361 occupied sites were 52% cattail, 18% sedges, 13% bur-reed, 7% miscellaneous, 5% river bulrush, and 5% hardstem bulrush; mean vegetation measurements of 957 1-m² quadrats on 71 territories were 128 cm visual obstruction, 121.9 stems/m², 38.4 cm water depth, and a category 2.6 (scale of 0-4 representing increasing amounts) for the amount of floating or submersed residual vegetation; the mean water depth at 420 sites along 50 random transects was somewhat deeper (44.1 cm) than at 957 sites in 71 territories (38.4 cm); eight brood-rearing ranges (both sexes combined) averaged 0.19 ha; five male ranges averaged 0.17 ha and three female ranges averaged 0.22 ha; brood-rearing ranges generally were bounded by upland and open water; mean distance moved between locations for eight individuals was 44 m
Kantrud and Stewart 1984 North Dakota Wetland Highest density was in fens, followed by seasonal, semipermanent, temporary, and alkali wetlands
Kaufmann 1971 Iowa Wetland Of 211 nests, 129 were in robust vegetation (cattail, hairy sedge [Carex lacustris], river bulrush, softstem bulrush, bur-reed, common reed, and sweetflag [Acorus calamus]), 70 were in fine vegetation (tussock sedge [Carex tuckermani], other sedges, reed canary grass [Phalarus arundinacea], bluejoint, prairie cordgrass [Spartina pectinata], woolgrass [Scirpus cyperinus], American water plantain [Alisma plantago-aquatica], and grasses), and 12 were in stands of multiple plant species
Kaufmann 1989 Iowa, Minnesota Wetland Of 49 nests, 38 were in robust emergent vegetation (cattail) (other nest sites were not described); three captive pairs defended territories of 45-55 m²
Lowther 1977 Alberta Wetland Of 49 nests, 39 were in areas dominated by sedges, three in cattail, three in spikerush (Eleocharis sp.), two in tall mannagrass (Glyceria grandis), one in rush (Juncus sp.), and one in marsh smartweed (Polygonum amphibium)
Manci and Rusch 1988, 1989 Wisconsin Wetland Densities were highest in deep-water cattail (characterized by a mean water depth of 29 cm), but Soras also were present in shallow-water cattail (characterized by a mean water depth of 7-10 cm), dry cattail (characterized by a mean water depth of 3 cm), river bulrush (characterized by a mean water depth of 7-10 cm), and sedges (characterized by <7 cm water depth)
Melvin and Gibbs 1994, 1996 Rangewide Wetland Nested in freshwater seasonal or semipermanent wetlands in areas dominated by cattail, sedges, bur-reed (Sparganium spp.), or bulrushes (Schoenoplectus spp. or Scirpus spp.) interspersed with floating beds of submerged vegetation or mudflats; occasionally nested in salt marshes; commonly nested near (not defined) the border between two vegetation types or near the boundary between vegetation and open water; nests were loosely woven baskets of emergent vegetation that were either placed on the surface of the water or suspended 5-30 cm above the surface of the water from stems of emergent vegetation; rails usually constructed an overhead canopy of emergent vegetation and a ramp of emergent vegetation leading up to the nest rim from the water's surface; height of the nest rim above water ranged from 5 to 23 cm; mean water depths at nest sites ranged from 5 to 42 cm (number of nest sites not available); multiple inactive nests near active nests were constructed and served as feeding and resting platforms
Mousley 1937 Canada (province not given) Wetland One nest was located in live cattail; nest rim was 28 cm above water and the bottom of the nest was 15 cm above water; water depth at the nest site was >30 cm
Naugle 1997, Naugle et al. 2001 South Dakota Wetland Presence in semipermanent wetlands was positively related to percent of wetland area that was vegetated and to the number of emergent plant species composing >10% of the vegetated wetland area; presence was negatively associated with total semipermanent wetland area within 25.9 km² of the study wetland and with grazing intensity of wetland shorelines; presence in seasonal wetlands was positively related to percent of the wetland area that was vegetated
Nicol 1938 Not given Wetland Nests were basket-like structures constructed of dead leaves of cattail, bur-reed, and blue flag (Iris); a canopy of vegetation was created by bending vegetation over the nest; one nest was located in American water plantain
Pospichal 1952, Pospichal and Marshall 1954 Minnesota Wetland Nests were loosely woven baskets in emergent vegetation; cattail was the most common plant species used to construct nests; nest bases were either in contact with the surface of the water or extended slightly below the water's surface; rails often built a ramp of vegetation up to the nest rim; multiple inactive nests were constructed and served as resting and feeding platforms; mean nest measurements for 52 nests were 11.7 cm (range of 5-23 cm) height of nest rim above water, and 21.6 cm (range of 5-42 cm) water depth; of 78 nests (including multiple, inactive nests), 66 were located in cattail, six in woolgrass, three in softstem bulrush, two in tall mannagrass, and one in water plantain (Alisma); commonly nested near (not defined) open water or near an edge between vegetation cover types
Rundle and Fredrickson 1981 Missouri Impoundment Migrant rails preferred moist-soil impoundments with water depths ranging from 5 to 15 cm and mixed stands of beggartick (Bidens spp.), late-flowering thoroughwort (Eupatorium serotinum), and barnyard grass (Echinochloa muricata and E. crusgalli); water depths at 53 occupied sites ranged from 0 to 46 cm and averaged 12.7 cm
Sayre and Rundle 1984 Missouri Impoundment Water depths (during both spring and fall migration) ranged from 0 to 46 cm at 97 flush sites, and 64% of flush sites had <15 cm of water. During spring migration, mean vegetation height at 42 flush locations was 30 cm and mean water depth was 13.7 cm; 10 of 23 rails were flushed from water >15 cm deep, 10 were flushed from water 5-15 cm deep, and three were flushed from water <5 cm deep; 12 of 23 rails were flushed from vegetation taller than 30 cm and 11 were flushed from vegetation <30 cm tall; 16 of 23 rails were flushed from dense (>30 contacts with a point-intercept sampling rod) vegetation and seven were flushed from sparse (5-30 contacts) vegetation; plant species at flush sites consisted of beggartick and broomsedge bluestem (Andropogon virginicus), sedge (Carex spp., Cyperus spp.), and rush (Juncus spp.). During fall migration, water depth averaged 9.3 cm at 55 flush locations, and mean vegetation height was 43 cm; 15 of 21 rails were flushed from water 5-15 cm deep, five were flushed from water >15 cm deep, and one was flushed from water <5 cm deep; 16 rails were flushed from vegetation >30 cm tall and five were flushed from vegetation <30 cm tall; 18 rails were flushed from dense (>30 contacts with a point-intercept sampling rod) vegetation and three were flushed from sparse (5-30 contacts) vegetation; plant species at flush sites consisted of pure and mixed stands of beggartick, late-flowering thoroughwort, and annual grasses (Panicum sp., Echinochloa spp., Digitaria sp.).
Schreiber 1994 Iowa Wetland, wetland (restored) Frequency of occurrence was greater for natural wetlands than for 1-yr-old restored wetlands; nested in six of seven natural and two of seven 4-yr-old restored wetlands; did not nest in 1-yr-old restored wetlands (the study did not examine restored wetlands older than 4 yr)
Schuster 1998 Iowa Wetland, wetland (restored) Frequency of occurrence was greater for natural wetlands than for wetlands that were restored 1 to 7 yr prior to the study; nested more frequently at natural wetlands (the study did not examine restored wetlands older than 7 yr)
Shutler et al. 2000 Saskatchewan Cropland, dense nesting cover (idle seeded-native, idle seeded-tame), wet meadow, wetland Occupied wetlands and wetland margins in areas of conventional tillage (applications of herbicides and tillage [≥3 times per year] to control weeds), minimum-tillage (reduced tillage [<3 times per year] and direct seeding into previous year's crop stubble), and organic farming (cultivation and crop rotation), as well as untilled areas; presence was negatively affected by area of open water within the wetland
Stewart 1975 North Dakota Wetland Occurred in fens, seasonal wetlands, and fresh to subsaline semipermanent wetlands that contained dense stands of emergent vegetation; three nests were found in alkali bulrush (Scirpus maritimus), three in sprangletop (Scolochloa festucacea), two in a mixture of slough sedge (Carex atherodes) and tall mannagrass, and two in a mixture of slough sedge and common spikerush (Eleocharis palustris)
Stewart and Kantrud 1965 North Dakota Wetland Commonly occurred in seasonal wetlands with closed stands of emergent cover or clumps of emergent cover interspersed with open water and fresh through brackish semipermanent wetlands with closed stands of emergent cover
Svedarsky 1992 Minnesota Impoundment, wetland, wetland (restored) Nested in fens and restored wetlands; of eight nests, two were in bulrush, two in sedges, one in cattail, one in willow (Salix spp.), and one was in a mixed stand of sedges and grasses (species not given); nests typically were 30 cm above water that was 25 cm deep; nests were 5-10 m from the edge of the wetland
Tacha 1975 Kansas Wetland, wetland complex Occurred in areas dominated by alkali bulrush, cattail, softstem bulrush, prairie cordgrass, and saltgrass (Distichlis spicata) with water levels ranging from 0 to 5 cm deep
Tanner 1953, Tanner and Hendrickson 1954 Iowa Wetland Of 35 nests, 25 were in hairy sedge, four in river bulrush, three in hardstem bulrush, two in bur-reed, and one in cattail; water depth at 26 nests ranged from 12.7 to 50.8 cm and averaged 32.5 cm; water depth at six nests ranged from 33 to 58.4 cm and averaged 48 cm; all nests had a ramp of vegetation leading from the water surface to the rim of the nest; a canopy of vegetation usually was formed over the nest
VanRees-Siewert 1993, VanRees-Siewert and Dinsmore 1996 Iowa Wetland, wetland (restored) Nested in one 2-yr-old restored wetland and were present in wetlands restored for 1-4 yr (the study did not examine restored wetlands older than 4 yr)
Walkinshaw 1940 Alberta, Michigan, North Dakota Lake, wetland Nested in wetlands or along lake margins with 15-20 cm of water and an abundance of sedges; water depth around eight nests averaged 18 cm and the nests averaged 14.7 cm above the water; nests were constructed of and woven into sedges, rushes (species not given), or grasses (species not given), and occasionally cattail or softstem bulrush; one nest was found in a newly flooded area in a clump of giant sumpweed (Iva xanthifolia)
Weber 1978, Weber et al. 1982 South Dakota Stream, wetland Preferred wetlands dominated by cattail; occurred most frequently on semipermanent ponds, followed by seasonal ponds, permanent streams, intermittent streams, and stock ponds; presence was positively related to the presence of semipermanent wetlands, wetlands with central expanses of open water composing >5% of the wetland area and surrounded by a peripheral band of emergent vegetation cover averaging ≥1.8 m in width, and to the area of seasonal ponds within a 64-ha block surrounding the wetland; presence was negatively related to the presence of wetlands composed of >95% open-water cover
Zimmerman 1984 Kansas Wetland Mean water depth at 17 occupied sites was 11.7 cm; at 43 occupied sites, mean vegetation height averaged 65.7 cm and percent open water averaged 23.8%

* In an effort to standardize terminology among studies, various descriptors were used to denote the management or type of habitat. "Idle" used as a modifier (e.g., idle tallgrass) denotes undisturbed or unmanaged (e.g., not burned, mowed, or grazed) areas. "Idle" by itself denotes unmanaged areas in which the plant species were not mentioned. Examples of "idle" habitats include weedy or fallow areas (e.g., oldfields), fencerows, grassed waterways, terraces, ditches, and road rights-of-way. "Tame" denotes introduced plant species (e.g., smooth brome [Bromus inermis]) that are not native to North American prairies. "Hayland" refers to any habitat that was mowed, regardless of whether the resulting cut vegetation was removed. "Burned" includes habitats that were burned intentionally or accidentally or those burned by natural forces (e.g., lightning). In situations where there are two or more descriptors (e.g., idle tame hayland),the first descriptor modifies the following descriptors. For example, idle tame hayland is habitat that is usually mowed annually but happened to be undisturbed during the year of the study.


Literature Cited

Allen, A. A. 1934. The Virginia Rail and the Sora. Bird Lore 36:196-204.

Allen, G. T., and P. Ramirez. 1990. A review of bird deaths on barbed-wire fences. Wilson Bulletin 102:553-558.

Andrews, D. A. 1973. Habitat utilization by Sora, Virginia Rails and King Rails near southwestern Lake Erie. M.S. thesis. Ohio State University, Columbus, Ohio. 112 pages.

Artmann, J. W., and E. M. Martin. 1975. Incidence of ingested lead shot in Sora Rails. Journal of Wildlife Management 39:514-519.

Avery, M., and T. Clement. 1972. Bird mortality at four towers in eastern North Dakota--fall 1972. Prairie Naturalist 4:87-95.

Baird, K. E. 1974. A field study of the King, Sora and Virginia rails at Cheyenne Bottoms in west-central Kansas. M.S. thesis. Kansas State University, Manhattan, Kansas. 38 pages.

Barger, N. R. 1958. Sora Rail. Wisconsin Conservation Bulletin 23:35.

Bent, A. C. 1963. Life histories of North American marsh birds. Dover Publications, Inc., New York, New York. 392 pages.

Berger, A. J. 1951. Nesting density of Virginia and Sora rails in Michigan. Condor 53:202.

Beule, J. D. 1979. Control and management of cattails in southeastern Wisconsin wetlands. Wisconsin Department of Natural Resources, Madison, Wisconsin. Technical Bulletin No. 112. 39 pages.

Billard, R. S. 1948. An ecological study of the Virginia Rail and the Sora in some Connecticut swamps, 1947. M.S. thesis. Iowa State College, Ames, Iowa. 84 pages.

Boeker, H. M. 1954. A census of populations of the Wilson's Snipe and Sora Rail in the Yampa River Valley, Colorado. Condor 56:105-106.

Boyer, G. F., and O. E. Devitt. 1961. A significant increase in the birds of Luther Marsh, Ontario, following freshwater impoundment. Canadian Field-Naturalist 75:225-237.

Brown, M., and J. J. Dinsmore. 1986. Implications of marsh size and isolation for marsh bird management. Journal of Wildlife Management 50:392-397.

Chapman, H. F. 1952. The Sora Rail. South Dakota Bird Notes 4:48.

Cooke, W. W. 1914. Distribution and migration of North American rails and their allies. Bulletin of the U.S. Department of Agriculture. No. 128. 50 pages.

Crawford, R. L. 1974. Bird casualties at a Leon County, Florida TV tower: October 1966-September 1973. Bulletin of the Tall Timbers Research Station. No. 18. 27 pages.

Crowley, S. K. 1994. Habitat use and population monitoring of secretive waterbirds in Massachusetts. M.S. thesis. University of Massachusetts, Amherst, Massachusetts. 108 pages.

Daub, B. C. 1993. Effects of marsh area and characteristics on avian diversity and nesting success. M.S. thesis. University of Michigan, Ann Arbor, Michigan. 37 pages.

Dault, R. E. 2001. Long-term effects of wetland restoration on bird communities in the Prairie Pothole Region of northwestern Iowa. M.S. thesis. Iowa State University, Ames, Iowa. 107 pages.

Delphey, P. J. 1991. A comparison of the bird and aquatic macroinvertebrate communities between restored and 'natural' Iowa prairie wetlands. M.S. thesis. Iowa State University, Ames, Iowa. 85 pages.

DeWeese, L. R., C. Lowell, L. A. S. McEwen, and R. D. Deblinger. 1983. Effects on birds of fenthion aerial application for mosquito control. Journal of Economic Entomology 76:906-911.

Dinsmore, S., E. Munson, J. J. Dinsmore, and G. M. Nelson. 1987. Two television tower kills in Iowa. Iowa Bird Life 57:5-8.

Dinsmore, J. J., R. B. Renken, and J. P. Schaufenbuel. 1983. TV tower kill in central Iowa. Iowa Bird Life 53:91-92.

Faanes, C. A. 1981. Birds of the St. Croix River Valley: Minnesota and Wisconsin. U.S. Fish and Wildlife Service, Washington, D.C. North American Fauna 73. 196 pages.

Faanes, C. A. 1982. Avian use of Sheyenne Lake and associated habitats in central North Dakota. U.S. Fish and Wildlife Service, Resource Publication 144. 24 pages.

Faanes, C. A., and G. R. Lingle. 1995. Breeding birds of the Platte River Valley of Nebraska. Northern Prairie Wildlife Research Center Online. http://www.npwrc.usgs.gov/resource/distr/birds/platte/platte.htm (Version 02SEP99).

Fairbairn, S. E., and J. J. Dinsmore. 2001. Factors associated with occurrence and density of wetland birds in the Prairie Pothole Region of Iowa. Journal of the Iowa Academy of Science 108:8-14.

Fallon, F. W. 1997. Sora and Pied-billed Grebe nesting in Kent County, Maryland. Maryland Birdlife 53:83-84.

Fannucchi, W. A. 1983. Wildlife use of wild rice beds and the impact of rice harvesting on wildlife in east central Minnesota. M.S. thesis. University of Wisconsin, Stevens Point, Wisconsin. 79 pages.

Fannucchi, W. A., G. T. Fannucchi, and L. E. Nauman. 1986. Effects of harvesting wild rice, Zizania aquatica, on Sora Rails. Canadian Field-Naturalist 100:533-536.

Fredrickson, L. H., and F. A. Reid. 1986. Wetland and riparian habitats: a nongame management overview. Pages 59-96 in J. B. Hale, L. B. Best, and R. L. Clawson, editors. Management of nongame wildlife in the Midwest: a developing art. North Central Section Wildlife Society, Chelsea, Michigan.

Gibbs, J. P., J. R. Longcore, D. G. McAuley, and J. K. Ringelman. 1991. Use of wetland habitats by selected nongame birds in Maine. U.S. Fish and Wildlife Service, Fish and Wildlife Research Report No. 9. 57 pages.

Gibbs, M. 1899. The Sora. Oologist 16:151-153.

Gillette, D. C. 1897. Notes on the Virginia and Sora rails. Oologist 14:21-23.

Glahn, J. F. 1974. Study of breeding rails with recorded calls in north-central Colorado. Wilson Bulletin 86:206-214.

Greenlaw, J. S., and R. F. Miller. 1982. Breeding Soras on a Long Island salt marsh. Kingbird 32:78-84.

Griese, H. J. 1977. Status and habitat utilization of rails in Colorado. M.S. thesis. Colorado State University, Fort Collins, Colorado. 67 pages.

Griese, H. J., R. A. Ryder, and C. E. Braun. 1980. Spatial and temporal distribution of rails in Colorado. Wilson Bulletin 92:96-102.

Hanowski, J. M., G. J. Niemi, R. Lima, and R. R. Regal. 1997. Response of breeding birds to mosquito control treatments of wetlands. Wetlands 17:485-492.

Hanson, W. R. 1952. Effects of some herbicides and insecticides on biota of North Dakota marshes. Journal of Wildlife Management 16:299-308.

Hartman, M. R. 1994. Avian use of restored and natural wetlands in north-central Indiana. M.S. thesis. Purdue University, West Lafayette, Indiana. 98 pages.

Helzer, C. J. 1996. The effects of wet meadow fragmentation on grassland birds. M.S. thesis. University of Nebraska, Lincoln, Nebraska. 65 pages.

Hemesath, L. M. 1991. Species richness and nest productivity of marsh birds on restored prairie potholes in northern Iowa. M.S. thesis. Iowa State University, Ames, Iowa. 87 pages.

Hemesath, L. M., and J. J. Dinsmore. 1993. Factors affecting bird colonization of restored wetlands. Prairie Naturalist 25:1-11.

Holliman, D. C. 1977. Rails and gallinules. Pages 118-121 in G. C. Sanderson, editor. Management of migratory shore and upland game birds in North America. International Association of Fish and Wildlife Agencies, Washington, D.C.

Horak, G. J. 1964. A comparative study of Virginia and Sora rails with emphasis on foods. M.S. thesis. Iowa State University, Ames, Iowa. 73 pages.

Horstman, A. J., J. R. Nawrot, and A. Woolf. 1998. Mine-associated wetlands as avian habitat. Wetlands 18:298-304.

Hoving, E. J., and S. G. Sealy. 1987. Species and age composition of a sample of birds killed in fall 1979 at a Manitoba TV tower. Prairie Naturalist 19:129-133.

Janssen, R. B. 1987. Birds in Minnesota. University of Minnesota Press, Minneapolis, Minnesota. 352 pages.

Johnsgard, P. A. 1979. Birds of the Great Plains. University of Nebraska Press, Lincoln, Nebraska. 539 pages.

Johnsgard, P. A. 1980. A preliminary list of the birds of Nebraska and adjacent Plains states. University of Nebraska, Lincoln, Nebraska. 156 pages.

Johnson, R. R. 1984. Breeding habitat use and postbreeding movements by Soras and Virginia Rails. M.S. thesis. Iowa State University, Ames, Iowa. 52 pages.

Johnson, R. R., and J. J. Dinsmore. 1985. Brood-rearing and postbreeding habitat use by Virginia Rails and Soras. Wilson Bulletin 97:551-554.

Johnson, R. R., and J. J. Dinsmore. 1986. Habitat use by breeding Virginia Rails and Soras. Journal of Wildlife Management 50:387-392.

Jorgensen, E. E., and L. E. Nauman. 1993. Bird distribution in wetlands associated with commercial cranberry production. Passenger Pigeon 55:289-298.

Kantrud, H. A., and R. E. Stewart. 1984. Ecological distribution and crude density of breeding birds on prairie wetlands. Journal of Wildlife Management 48:426-437.

Kaufmann, G. W. 1971. Behavior and ecology of the Sora, Porzana carolina, and Virginia Rail, Rallus limicola. Ph.D. dissertation. University of Minnesota, Minneapolis, Minnesota. 114 pages.

Kaufmann, G. W. 1989. Breeding ecology of the Sora, Porzana carolina, and the Virginia Rail, Rallus limicola. Canadian Field-Naturalist 103:270-282.

Kemper, C. A., D. G. Raveling, and D. W. Warner. 1966. A comparison of the species composition of two TV tower killed samples from the same night of migration. Wilson Bulletin 78:26-30.

Kent, T. H., and J. J. Dinsmore. 1996. Birds in Iowa. Published by the authors, Iowa City and Ames, Iowa. 391 pages.

Knapton, R. W. 1979. Birds of the Gainsborough-Lyleton region. Saskatchewan Natural History Society Special Publication 10. 72 pages.

Knight, R. L., J. Skriletz, and D. C. Ryan. 1980. Four additional cases of bird mortality on barbed wire fences. Western Birds 11:202.

Krapu, G. L., and R. K. Green. 1978. Breeding bird populations of selected semipermanent wetlands in south-central North Dakota-1977. American Birds 32:110-112.

Lariviere, S., and M. Lepage. 2000. Effect of water-level increase on use by birds of a lakeshore fen in Quebec. Canadian Field-Naturalist 114:694-696.

Lindmeier, J. P. 1960. Plover, rail and godwit nesting on a study area in Mahnomen County, Minnesota. Flicker 32:5-9.

Linz, G. M., D. L. Bergman, D. C. Blixt, and C. McMuri. 1997. Response of American Coots and Soras to herbicide-induced vegetation changes in wetlands. Journal of Field Ornithology 68:450-457.

Lowther, J. K. 1977. Nesting biology of the Sora at Vermilion, Alberta. Canadian Field-Naturalist 91:63-67.

Malcolm, J. M. 1982. Bird collisions with a power transmission line and their relation to botulism at a Montana wetland. Wildlife Society Bulletin 10: 297-304.

Manci, K. M., and D. H. Rusch. 1988. Indices to distribution and abundance of some inconspicuous waterbirds on Horicon Marsh. Journal of Field Ornithology 59:67-75.

Manci, K. M., and D. H. Rusch. 1989. Waterbird use of wetland habitats identified by infrared aerial photography. Pages 1045-1058 in R. R. Sharitz and J. W. Gibbons, editors. Freshwater wetlands and wildlife. Proceedings of a symposium held at Charleston, South Carolina, March 24-27, 1986. U.S. Department of Energy, Office of Scientific and Technical Information, Oak Ridge, Tennessee.

Marshall, W. H. 1952. Waterfowl of three prairie potholes. Flicker 24:60-68.

Meanley, B. 1960. Fall food of the Sora Rail in the Arkansas rice fields. Journal of Wildlife Management 24:339.

Meeks, R. L. 1968. The accumulation of 36C1 ring-labeled DDT in a freshwater marsh. Journal of Wildlife Management 32:376-398.

Melvin, S. M., and J. P. Gibbs. 1994. Sora. Pages 209-217 in T. C. Tacha and C. E. Braun, editors. Management of migratory shore and upland game birds in North America. International Association of Fish and Wildlife Agencies, Washington, D.C.

Melvin, S. M., and J. P. Gibbs. 1996. Sora (Porzana carolina). A. Poole and F. Gill, editors. The birds of North America, No. 250. The Academy of Natural Sciences, Philadelphia, Pennsylvania; The American Ornithologists' Union, Washington, D.C.

Miller, R. F. 1928. Virginia Rail lays in Sora's nest. Oologist 45:132.

Mousley, H. 1937. A study of a Virginia Rail and Sora Rail at their nests. Wilson Bulletin 49:80-84.

National Geographic Society. 1999. Field guide to the birds of North America, third edition. National Geographic Society, Washington, D.C. 480 pages.

Naugle, D. E. 1997. Habitat area requirements of prairie wetland birds in eastern South Dakota. Ph.D. dissertation. South Dakota State University, Brookings, South Dakota. 85 pages.

Naugle, D. E., R. R. Johnson, and K. F. Higgins. 2001. A landscape approach to conserving wetland bird habitat in the Prairie Pothole Region of eastern South Dakota. Wetlands 21:1-17.

Nauman, E. D. 1927. Notes on rails. Wilson Bulletin 39:217-219.

Nicol, A. C. 1938. A nest of the Sora Rail. Canadian Field-Naturalist 52: 55-57.

Odom, R. R. 1975. Mercury contamination in Georgia rails. Proceedings of the Annual Conference of the Southeastern Association of Game and Fish Commissioners 28:649-658.

Odom, R. R. 1977. Sora (Porzana carolina). Pages 57-65 in G. C. Sanderson, editor. Management of migratory shore and upland game birds in North America. International Association of Fish and Wildlife Agencies, Washington, D.C.

Parmelee, D. F., M. D. Schwilling, and H. A. Stephens. 1970. Gruiform birds of Cheyenne Bottoms. Kansas Ornithological Society Bulletin 21:25-27.

Peterson, T. L., and J. A. Cooper. 1987. Impacts of center pivot irrigation systems on birds in prairie wetlands. Journal of Wildlife Management 51:238-247.

Pospichal, L. B. 1952. A field study of Sora Rail (Porzana carolina) and Virginia Rail (Rallus limicola) populations in central Minnesota. M.S. thesis. University of Minnesota, St. Paul, Minnesota. 80 pages.

Pospichal, L. B., and W. H. Marshall. 1954. A field study of Sora Rail and Virginia Rail in central Minnesota. Flicker 26:2-32.

Prescott, D. R. C., A. J. Murphy, and E. Ewaschuk. 1995. An avian community approach to determining biodiversity values of NAWMP habitats in the aspen parkland of Alberta. NAWMP-012. Alberta NAWMP Centre, Edmonton, Alberta. 58 pages.

Rundle, W. D., and L. H. Fredrickson. 1981. Managing seasonally flooded impoundments for migrant rails and shorebirds. Wildlife Society Bulletin 9:80-87.

Rundle, W. D., and M. W. Sayre. 1983. Feeding ecology of migrant Soras in southeastern Missouri. Journal of Wildlife Management 47:1153-1159.

Sayre, M. W., and W. D. Rundle. 1984. Comparison of habitat use by migrant Soras and Virginia Rails. Journal of Wildlife Management 48:599-605.

Schreiber, J. A. 1994. Structure of breeding-bird communities on natural and restored Iowa wetlands. M.S. thesis. Iowa State University, Ames, Iowa. 85 pages.

Schuster, J. E. 1998. Avian community composition and diversity in natural and restored central Iowa wetlands. M.S. thesis. Iowa State University, Ames, Iowa. 74 pages.

Shutler, D., A. Mullie, and R. G. Clark. 2000. Bird communities of prairie uplands and wetlands in relation to farming practices in Saskatchewan. Conservation Biology 14:1441-1451.

Smith, A. B. 1955. Sora Rail populations in Alberta, 1953-54. Pages 59-62 in Investigations of woodcock, snipe, and rails in 1954. U.S. Fish and Wildlife Service, Science Report 28.

Sorenson, M. D. 1995. Evidence of conspecific nest parasitism and egg discrimination in the Sora. Condor 97:819-821.

Stendell, R. C., J. W. Artmann, and E. Martin. 1980. Lead residues in Sora Rails from Maryland. Journal of Wildlife Management 44:525-527.

Stewart, R. E. 1975. Breeding birds of North Dakota. Tri-College Center for Environmental Studies, Fargo, North Dakota. 295 pages.

Stewart, R. E., and H. A. Kantrud. 1965. Ecological studies of waterfowl populations in the prairie potholes of North Dakota. U.S. Fish and Wildlife Service, Bureau of Sport Fisheries and Wildlife. 1965 Progress Report. 14 pages.

Stewart, R. E., and H. A. Kantrud. 1971. Classification of natural ponds and lakes in the glaciated prairie region. Resource Publication 92. U.S. Fish and Wildlife Service, Bureau of Sport Fisheries and Wildlife. 57 pages.

Svedarsky, W. D. 1992. Biological inventory of a multi-purpose flood control impoundment in northwestern Minnesota and potentials for nongame and game bird management. Final Report. Northwest Agricultural Experiment Station, University of Minnesota, Crookston, Minnesota. 115 pages.

Tacha, R. W. 1975. A survey of rail populations in Kansas, with emphasis on Cheyenne Bottoms. M.S. thesis. Kansas State College, Fort Hays, Kansas. 54 pages.

Tanner, W. D. 1953. Ecology of the Virginia and King rails and the Sora in Clay County, Iowa. Ph. D. dissertation. Iowa State College, Ames, Iowa. 154 pages.

Tanner, W. D., and G. O. Hendrickson. 1954. Ecology of the Virginia Rail in Clay County, Iowa. Iowa Bird Life 24:65-70.

Thompson, L. S. 1978. Transmission line wire strikes: mitigation through engineering design and habitat modification. Pages 27-52 in M. L. Avery, editor. Impacts of transmission lines on birds in flight. Publication 78/48, U.S. Fish and Wildlife Service, Office of Biological Services, Washington, D.C.

Tordoff, H. B., and R. M. Mengel. 1956. Studies of birds killed in nocturnal migration. University of Kansas, Publication of the Museum of Natural History 10:1-44. Lawrence, Kansas.

VanRees-Siewert, K. L. 1993. The influence of wetland age on bird and aquatic macroinvertebrate use of restored Iowa wetlands. M.S. thesis. Iowa State University, Ames, Iowa. 96 pages.

VanRees-Siewert, K. L., and J. J. Dinsmore. 1996. Influence of wetland age on bird use of restored wetlands in Iowa. Wetlands 16:577-582.

Vogel, J. A. 1999. Migration chronology and habitat use of webless migratory game birds in lower Missouri River floodplain wetlands. M.S. thesis. University of Missouri, Columbia, Missouri. 79 pages.

Walkinshaw, L. H. 1940. Summer life of the Sora rail. Auk 57:153-168.

Weber, M. J. 1978. Non-game birds in relation to habitat variation on South Dakota wetlands. M.S. thesis. South Dakota State University, Brookings, South Dakota. 54 pages.

Weber, M. J., P. A. Vohs, Jr., and L. D. Flake. 1982. Use of prairie wetlands by selected bird species in South Dakota. Wilson Bulletin 94:550-554.

Weller, M. W. 1999. Wetland birds: habitat resources and conservation implications. Cambridge University Press, Cambridge, New York. 271 pages.

Whitt, M. B., H. H. Prince, and R. R. Cox, Jr. 1999. Avian use of purple loosestrife dominated habitat relative to other vegetation types in a Lake Huron wetland complex. Wilson Bulletin 111:105-114.

Wolfe, D. H. 1993. Sora impaled on barbed wire fence. Bulletin of the Oklahoma Ornithological Society 26:28-29.

Zimmerman, J. L. 1984. Distribution, habitat, and status of the Sora and Virginia Rail in eastern Kansas. Journal of Field Ornithology 55:38-47.

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