The sora (''Porzana carolina'') is a small waterbird of the rail family
Rallidae
The rails, or Rallidae, are a large cosmopolitan family of small- to medium-sized, ground-living birds. The family exhibits considerable diversity and includes the crakes, coots, and gallinules. Many species are associated with wetlands, althou ...
, sometimes also referred to as the sora rail or sora crake, that occurs throughout much of North America. The genus name ''Porzana'' is derived from
Venetian terms for small rails, and the specific ''carolina'' refers to the
Carolina Colony
Province of Carolina was a province of England (1663–1707) and Great Britain (1707–1712) that existed in North America and the Caribbean from 1663 until partitioned into North and South on January 24, 1712. It is part of present-day Alabama ...
. The common name "Sora" is probably taken from a Native American language.
Adult soras are long, with dark-marked brown upperparts, a blue-grey face and underparts, and black and white barring on the flanks. They have a short thick yellow bill, with black markings on the face at the base of the bill and on the throat. Sexes are similar, but young soras lack the black facial markings and have a whitish face and buff breast. They weigh about .
The sora's breeding habitat is
marsh
A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found a ...
es throughout much of
North America. They nest in a well-concealed location in dense vegetation. The female usually lays 10 to 12
egg
An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...
s, sometimes as many as 18, in a cup built from marsh vegetation. The eggs do not all hatch together. Both parents
incubate and feed the young, who leave the nest soon after they hatch and are able to fly within a month.
They
migrate to the southern
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
and northern
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
. Sora is a very rare vagrant to western
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
, where it can be confused with
spotted crake
The spotted crake (''Porzana porzana'') is a small waterbird of the family Rallidae. The scientific name is derived from Venetian terms for small rails.
The spotted crake's breeding habitat is marshes and sedge beds across temperate Europe into ...
. However, the latter species always has spotting on the breast. a streaked crown stripe, and a different wing pattern.
Soras forage while walking or swimming. They are
omnivores, eating
seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...
s,
insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...
s and
snail
A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class G ...
s. Although soras are more often heard than seen, they are sometimes seen walking near open water. They are fairly common, despite a decrease in suitable habitat in recent times. The call is a slow whistled ''ker-whee'', or a descending whinny. The use of call broadcasts greatly increases the chances of hearing a sora. Call broadcasts can also increase the chances of seeing a sora, as they will often investigate the source of the call.
Taxonomy
The sora was
formally described by the Swedish naturalist
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...
in 1758 in the
tenth edition of his ''
Systema Naturae''. He placed it with the rails in the
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
''
Rallus
''Rallus'' is a genus of wetland birds of the rail family. Sometimes, the genera ''Lewinia'' and ''Gallirallus'' are included in it. Six of the species are found in the Americas, and the three species found in Eurasia, Africa and Madagascar ar ...
'' and coined the
binomial name ''Rallus carolinus''. Linnaeus based his description on the "little American water hen" that
George Edwards had described and illustrated in 1750 from a specimen collected near the Hudson Bay. Linnaeus also cited
Mark Catesby
Mark Catesby (24 March 1683 – 23 December 1749) was an English naturalist who studied the flora and fauna of the New World. Between 1729 and 1747 Catesby published his ''Natural History of Carolina, Florida and the Bahama Islands'', the fi ...
who had described the "soree" in his ''The Natural History of Carolina, Florida and the Bahama Islands''. The sora is now placed in the genus ''
Porzana
''Porzana'' is a genus of birds in the crake and rail family, Rallidae. Its scientific name is derived from Venetian terms for small rails. The spotted crake (''P. porzana'') is the type species.
Taxonomy
The genus ''Porzana'' was erected by t ...
'' that was erected in 1816 by the French ornithologist
Louis-Pierre Vieillot.
The genus name is derived from
Venetian terms for small rails, the specific epithet refers to the
Carolina Colony
Province of Carolina was a province of England (1663–1707) and Great Britain (1707–1712) that existed in North America and the Caribbean from 1663 until partitioned into North and South on January 24, 1712. It is part of present-day Alabama ...
. The common name "Sora" is probably taken from a Native American language.
The species in
monotypic
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...
: no
subspecies are recognised.
[
]
Description
Adult soras are long, with dark-marked brown upperparts, a blue-grey face and underparts, and black and white barring on the flanks. They have a short thick yellow bill, with black markings on the face at the base of the bill and on the throat. Sexes are similar, but young soras lack the black facial markings and have a whitish face and buff breast. They weigh about and have a wingspan of 35–40 cm. Soras have two common calls: a loud, squeaking "whinny" that decelerates and descends in pitch, often used to advertise territories; and a softer, ascending "ker-wee" or "sor-ah".[Cornell Lab of Ornithology. 2022]
Sora: Sounds
In: All about birds: Bird guide. Ithaca, NY: Cornell University, Cornell Lab of Ornithology The latter call is sometimes presented as a possible origin for the species' common name.
Distribution and habitat
The sora is common across North America, naturally occurring in 49 US states (the exception being Hawaii), all 10 Canadian provinces and 2 Canadian territories. Outside of US/Canada, the species is found throughout Central America, the Caribbean, and northern South America. The species has been recorded as a vagrant
Vagrancy is the condition of homelessness without regular employment or income. Vagrants (also known as bums, vagabonds, rogues, tramps or drifters) usually live in poverty and support themselves by begging, scavenging, petty theft, temporar ...
in Iceland
Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
, Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It i ...
, Portugal
Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...
, and at Lake Titicaca
Lake Titicaca (; es, Lago Titicaca ; qu, Titiqaqa Qucha) is a large freshwater lake in the Andes mountains on the border of Bolivia and Peru. It is often called the highest navigable lake in the world. By volume of water and by surface area, i ...
.
Soras occur throughout most of North America.[ Soras breed from Nova Scotia northwest 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 Caribbean, northern portions of South America, including Ecuador, Colombia, 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.][Cornell Lab of Ornithology. 2003]
Sora
In: All about birds: Bird guide. Ithaca, NY: Cornell University, Cornell Lab of Ornithology
The size of an individual Sora's home range varies. Sora brood-rearing home ranges in northwestern Iowa averaged .[ In Arizona, sora home range size varied from in the early breeding season to over in the postbreeding season. These seasonal differences in sora home range size were not significant (p>0.05).][
Densities vary from to 12 soras/acre in Colorado ][ to 0.47 pair/ha in Indiana.][ An average of 1.3 soras/ha responded to calls across sites in Colorado.][ A similar density of soras was found in southeastern Wisconsin.][ In Iowa, average density over 2 years and several marsh habitats was 1.3 pairs/ha.][
≥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 ][ and were significantly (p<0.05) positively related to area of wetlands in Saskatchewan.][ In Maine, soras used 10% of wetlands, 40% to 50% of wetlands from in size, and 20% of wetlands larger than .][ In western New York, soras were significantly (p=0.007) more abundant in marshes from in size than in smaller (< ) or larger () marshes. In addition, sora nests were detected more often in the marshes.][
Soras are commonly reported in plant communities dominated by ]cattails
''Typha'' is a genus of about 30 species of monocotyledonous flowering plants in the family Typhaceae. These plants have a variety of common names, in British English as bulrush or reedmace, in American English as reed, cattail, or punks, in ...
(''Typha'' spp.),[Lor, Socheata Krystyne. 2000. Population status and breeding ecology of marsh birds in western New York. Ithaca, NY: Cornell University, Department of Natural Resources. Thesis][ ]sedges
The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus ''Carex'' wit ...
(''Carex'' spp.),[ ]bulrushes
Bulrush is a vernacular name for several large wetland graminoid, grass-like plants
*Sedge family (Cyperaceae):
**''Cyperus''
**''Scirpus''
**''Blysmus''
**''Bolboschoenus''
**''Scirpoides''
**''Isolepis''
**''Schoenoplectus''
**''Trichophorum''
...
(''Scirpus'' spp.),[ smartweeds (''Polygonum'' spp.),][ rushes (''Juncus'' spp.),][ rice cutgrass (''Leersia oryzoides''),][ and barnyard grasses (''Echinochloa'' spp.).][Rundle, William Dean. 1980. Management, habitat selection, and feeding ecology of migrant rails and shorebirds. Columbia, MO: University of Missouri. Thesis][
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.][ In Arizona, habitat edges were closer to sora heavy use areas than random sites.][
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.][
Outside of wetlands, soras are most often reported in cultivated areas during migration or in the postbreeding period. For instance, a sora was observed from marshland in a cultivated field in Iowa in the middle of August. A male sora was observed less than from a large wetland in a soybean (''Glycine max'') field in northwestern Iowa during the postbreeding period.][ From early June to mid-July, soras were observed on farms in Saskatchewan sown mainly with wheat (''Triticum aestivum'').][
Soras have also been reported in flooded wooded areas.][Gibbs, James P.; Longcore, Jerry G.; McAuley, Daniel G.; Ringelman, James K. 1991. Use of wetland habitats by selected non-game water birds in Maine. Fish and Wildlife Research No. 9. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service] 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".[ 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.][ 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.][ Soras were observed at low abundances on a site with ]douglas-fir
The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three va ...
(''Pseudotsuga menziesii''), ponderosa pine
''Pinus ponderosa'', commonly known as the ponderosa pine, bull pine, blackjack pine, western yellow-pine, or filipinus pine is a very large pine tree species of variable habitat native to mountainous regions of western North America. It is the ...
(''Pinus ponderosa''), and trembling aspen (''Populus tremuloides'') in British Columbia.[Morgan, K. H.; Wetmore, S. P.; Smith, G. E. J.; Keller, R. A. 1989. Relationships between logging methods, habitat structure, and bird communities of the dry interior Douglas-fir, ponderosa pine forests of British Columbia. Technical Report Series No. 71. Delta, BC: Canadian Wildlife Service, Pacific and Yukon Region]
Soras use areas with a wide range of water depths. They are often observed in water less than deep,[ although the average water depth of sora heavy-use areas in Arizona was .][ In northwestern Iowa, average water depth in sora territories was , which was significantly (p<0.025) more shallow than water depths at random locations in the marsh.][ Sora nesting sites occurred in shallower water than random sites in western New York.][ Average water depths reported at nest sites range from for 4 sora nests in Colorado to nearly for sora nests in western New York.][ In areas of deep water, soras typically wade on mats of floating vegetation.][
Water level fluctuations may result in nest abandonment. For example, at a site in Colorado where water level increased more than , a sora nest with 7 eggs was abandoned.][ 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.][
Soras use areas with shallower water in fall than in spring.][Conway, Courtney J. 1990. Seasonal changes in movements and habitat use in three sympatric rails. Laramie, WY: University of Wyoming. Thesis][Reid, Frederic Arthur. 1989. Differential habitat use by waterbirds in a managed wetland complex. Columbia, MO: University of Missouri. Dissertation.] 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 [ and sora relative abundance in Saskatchewan.][ In western New York, sora nesting sites had a lower percentage of open water than random sites,][ and in Arizona soras used open water areas less than their availability.][
Sora nesting sites had larger percentage of emergent vegetation than random sites in marshes of western New York.][ Sora numbers in wetlands of northeastern North Dakota were significantly (p<0.05) positively correlated (r=0.45) with hectares of live emergent vegetation. In east and central Maine, wetlands used by soras had significantly (p=0.01) greater area of emergent vegetation than unused wetlands.][
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 ][ to 333 stems/m2 on sites in northeastern Missouri used during fall migration.][ 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.][ However, average stem density on sora territories was not significantly (p>0.05) different from random sites in northwestern Iowa.][
Height of emergent vegetation in sora habitat also varies. It ranged from in the spring after a winter disturbance in northwestern Iowa ][ to in areas heavily used by soras in Arizona.][ In marshes of western New York, average vegetation height at sora nesting sites was shorter than at random locations.][ 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.][
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.][ The availability of habitat in different seasons is another possible source of seasonal differences in sora habitat.][
Extent of woody vegetation surrounding South Dakota wetlands was not significantly (p=0.6) associated with sora occurrence. 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.][
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
Bulrush is a vernacular name for several large wetland graminoid, grass-like plants
*Sedge family (Cyperaceae):
**''Cyperus''
**''Scirpus''
**''Blysmus''
**''Bolboschoenus''
**''Scirpoides''
**''Isolepis''
**''Schoenoplectus''
**''Trichophorum''
...
and a mixed-shrub community were also used more than their availability, while saltcedar
The genus ''Tamarix'' (tamarisk, salt cedar, taray) is composed of about 50–60 species of flowering plants in the family Tamaricaceae, native to drier areas of Eurasia and Africa. The generic name originated in Latin and may refer to the Tam ...
(''Tamarix chinensis'') and arrowweed (''Pluchea sericea'') were avoided.[ A literature review notes sora avoidance of ]purple loosestrife
''Lythrum salicaria'' or purple loosestrifeFlora of NW Europe''Lythrum salicaria'' is a flowering plant belonging to the family Lythraceae. It should not be confused with other plants sharing the name loosestrife that are members of the family Pr ...
(''Lythrum salicaria'')-dominated sites. 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
''Laurus nobilis'' is an aromatic evergreen tree or large shrub with green, glabrous (smooth) leaves. It is in the flowering plant family Lauraceae. It is native to the Mediterranean region and is used as bay leaf for seasoning in cookin ...
(''Kalmia'' spp.).[ 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 ][ 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'' is a genus of about 30 species of monocotyledonous flowering plants in the family Typhaceae. These plants have a variety of common names, in British English as bulrush or reedmace, in American English as reed, cattail, or punks, in ...
(''Typha'' spp.) survey areas than in sedge areas. 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.[ In addition, soras' use of glaucous cattail (''Typha × glauca''), broadfruit bur-reed (''Sparganium eurycarpum''), ]sedge
The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus '' Carex'' ...
, river bulrush (''Schoenoplectus fluviatilis''), and hardstem bulrush (''S. acutus var. acutus'') habitats in marshes of northwestern Iowa generally reflected availability of these habitats.[
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
''Persicaria amphibia'' ( syn. ''Polygonum amphibium'') is a species of flowering plant in the knotweed family known by several common names, including longroot smartweed, water knotweed, water smartweed, and amphibious bistort. It is native to ...
(''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.[ 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.][
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 ≤ , soras were more abundant than the closely related ]Virginia rail
The Virginia rail (''Rallus limicola'') is a small waterbird, of the family Rallidae.
These birds remain fairly common despite continuing loss of habitat, but are secretive by nature and more often heard than seen. They are also considered a ga ...
(''Rallus limicola''), while on warmer sites the sora to Virginia rail ratio declined.[
]
Migration
They migrate to the southern United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
, the Caribbean, and northern South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
. Sora is a very rare vagrant to western Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
, where it can be confused with spotted crake
The spotted crake (''Porzana porzana'') is a small waterbird of the family Rallidae. The scientific name is derived from Venetian terms for small rails.
The spotted crake's breeding habitat is marshes and sedge beds across temperate Europe into ...
. However, the latter species always has spotting on the breast. a streaked crown stripe, and a different wing pattern.
Soras forage while walking or swimming. They are omnivores, eating seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...
s, insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...
s and snail
A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class G ...
s. Although soras are more often heard than seen, they are sometimes seen walking near open water. They are fairly common, despite a decrease in suitable habitat in recent times. The call is a slow whistled ''ker-whee'', or a descending whinny. The use of call broadcasts greatly increases the chances of hearing a sora. Call broadcasts can also increase the chances of seeing a sora, as they will often investigate the source of the call.
Sora's 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. In southeast Missouri, soras were observed from 25 March to 6 May.[ Soras were first detected in April to early May in Colorado,][ Iowa, and Minnesota.][ In a summary of the first detections of soras in Minnesota, Manitoba, and Saskatchewan, all occurred in April.][
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.][ Although local movements may obscure migration occurring in July, most migration occurred in August and September in Colorado. In northern Ohio, sora abundance was increased in late August and September by migrating individuals.][ In southeastern Missouri, soras were observed from 5 September to 27 October.][ Soras have been observed in Manitoba and Saskatchewan as late as October.][
]
Behavior and ecology
Breeding
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.[ 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.][ Studies from northern Ohio,][ North Dakota, and Alberta ][ report nesting from May to July. In a review, sora nests with eggs were recorded from early May to early July in Indiana.][
The sora's breeding habitat is ]marsh
A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found a ...
es throughout much of North America. They nest in a well-concealed location in dense vegetation. The female usually lays 10 to 12 egg
An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...
s, sometimes as many as 18, in a cup built from marsh vegetation. The eggs do not all hatch together. Both parents incubate and feed the young, who leave the nest soon after they hatch and are able to fly within a month.
Sora females begin construction of saucer-shaped nests on the ground or on a platform over shallow water at the start of egg laying.[ ]Clutch size
__NOTOC__
A clutch of egg (biology), eggs is the group of eggs produced by birds, amphibians, or reptiles, often at a single time, particularly those laid in a nest.
In birds, destruction of a clutch by predators (or removal by humans, for exam ...
s typically range from 8 to 13 eggs,[Mumford, Russell E.; Keller, Charles E. (1984). The birds of Indiana. Bloomington, IN: Indiana University Press ] although clutch sizes of up to 16 have been reported.[ Both parents incubate the eggs. Incubation lasts approximately 19 days, although a wide range of incubation periods has been reported in the literature.][ Eggs hatch over a span of 2 to 13 days.][ Nestlings are precocial and are capable of walking and swimming short distances (< ) by the end of their first day. Young soras are independent by about 4 weeks of age.][DeGraaf, Richard M.; Yamasaki, Mariko. 2001. New England wildlife: Habitat, natural history, and distribution. Hanover, NH: University Press of New England] Soras brood once per season.[ Some late broods may be second nesting attempts, but there is only one report in the literature of a second brood attempt after a successful nest.][ For information on breeding behavior of soras, see.][ For information on conspecific nest parasitism and egg discrimination in soras see.][
Sora nest success rates vary across locations and years. In the literature addressing sora apparent nest success, the proportions of successful nests varied from 0.61 in Michigan to 0.833 in Minnesota.][ In western New York, the nest success rate of 6 sora nests was 0.43, and the daily nest success rate was 0.97.][ 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).][ 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.][ During late summer, soras are flightless for a period during their post-nuptial molt.][
]
Food and feeding
Soras eat a wide range of foods. Animals that are commonly reported as sora food items include snails
A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastro ...
(Gastropoda), crustaceans
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean gro ...
(Crustacea), spiders
Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species di ...
(Araneae), and insects
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of j ...
(Insecta), mainly beetles (Coleoptera), grasshoppers (Orthoptera), flies
Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced m ...
(Diptera), and dragonflies
A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threa ...
(Odonata).[ Soras often eat the seeds of plants, such as smartweeds, ]bulrushes
Bulrush is a vernacular name for several large wetland graminoid, grass-like plants
*Sedge family (Cyperaceae):
**''Cyperus''
**''Scirpus''
**''Blysmus''
**''Bolboschoenus''
**''Scirpoides''
**''Isolepis''
**''Schoenoplectus''
**''Trichophorum''
...
, sedges
The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus ''Carex'' wit ...
, and barnyard grasses.[ Seeds of annual wildrice (''Zizania aquatica'') and rice cutgrass are eaten by soras in the eastern United States.][Martin, Alexander C.; Zim, Herbert S.; Nelson, Arnold L. (1951). American wildlife and plants. New York: McGraw-Hill Book Company, Inc.] A literature review lists crowngrass (''Paspalum'' spp.) and rice
Rice is the seed of the grass species '' Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera '' Zizania'' and '' Porteresia'', both wild and domesticat ...
(''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
Lemnoideae is a subfamily of flowering aquatic plants, known as duckweeds, water lentils, or water lenses. They float on or just beneath the surface of still or slow-moving bodies of fresh water and wetlands. Also known as bayroot, they arose ...
(Lemnaceae), pondweeds (''Potamogeton'' spp.), panicgrasses (''Panicum'' spp.), cordgrasses (''Spartina'' spp.), and saltgrass (''Distichlis spicata'').[
Soras eat more plant food in fall and winter (68%–69%) than in spring and summer (40%).][ 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
Physidae, common name the bladder snails, is a monophyletic taxonomic family of small air-breathing freshwater snails, aquatic pulmonate gastropod molluscs in the superfamily Lymnaeoidea .MolluscaBase eds. (2021). MolluscaBase. Physida ...
family.[
]
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.[ Likely causes of mortality are predation and human-caused sources such as road kill.][
Sora eggs are eaten by several species including American minks (''Neogale vison''), ]skunks
Skunks are mammals in the family Mephitidae. They are known for their ability to spray a liquid with a strong, unpleasant scent from their anal glands. Different species of skunk vary in appearance from black-and-white to brown, cream or ging ...
(Mephitidae), coyotes
The coyote (''Canis latrans'') is a species of canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecological nich ...
(''Canis latrans''), grackles (''Quiscalus'' spp.), crows
The Common Remotely Operated Weapon Station (CROWS) is a series of remote weapon stations used by the US military on its armored vehicles and ships. It allows weapon operators to engage targets without leaving the protection of their vehicle. ...
(''Corvus'' spp.), and herons
The herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera ''Botaurus'' and ''Ixobrychus ...
(Ardeidae).[Andrews, Douglas Alexander. 1973. Habitat utilization by sora, Virginia Rails, and King Rails near southwestern Lake Erie. Columbus, OH: Ohio State University. Thesis] Predation of adult soras by American minks, coyotes, and hawks and owls have been reported.[
]
References
External links
*
*
Sora Species Account
– Cornell Lab of Ornithology
– USGS Patuxent Bird Identification InfoCenter
*
{{Authority control
Porzana
Birds of Canada
Birds of North America
Native birds of the West Coast of the United States
Native birds of the Western United States
Birds of the Caribbean
Birds of Hispaniola
Birds of the Dominican Republic
Birds of Haiti
Birds described in 1758
Taxa named by Carl Linnaeus