Newly Opened Saline Wetland Tract Attracts Wildbirds

A recently opened tract of saline wetlands north of Lincoln has been an exciting place to visit for area birders.

Marsh Wren Community Wetlands "just opened in July and most birders weren't aware of it until September when I told Esa Jarvi about it and that's when he started promoting it on NEBirds," said Shari Schwartz, of Lincoln who has visited the area a few times.

"A mixture of available habitat is a factor that explains the extended list of species," Schwartz said. "A walk along the path leads past saline habitats with narrow-leaf cattails that host good marsh sparrows, wooded edges that attract accipiters and sparrows that utilize brush, seedy prairie patches for grassland sparrows, and a pond for ducks that has shallow edges bordered with cattails that houses rails and bitterns. There's even a bald eagle nest that hopefully will be active this spring."

"It's fun to explore a place that is somewhat yet undiscovered," said Schwartz. "The unit was so new and untrammeled, there wasn't a single scrap of litter in the new gravel parking lot. That was a memorable moment in my life!"

"It's really awesome it was protected because you can see housing has already gone in on the east border of the property," said Schwartz. "One concern I noticed was the source of the emergent springs is at the base of a hill where there's a private corn field that you can guarantee is depositing all kinds of pesticide and fertilizer into the ground water there. The Lower Platte South NRD (LPSNRD) co-manages it so you'd think they'd care about that but there's likely nothing they can do about that adjacent private property."

Management goals for the area include, said Tom Malmstrom, saline wetlands coordinator for the NRD:

• Restore a source of saline ground water to the historical basins.
  
• Manipulate the surface water hydrology providing multiple benefits for migratory avian species, halophytes, fresh water and saline water dependent non migratory species.
  
• Utilize the restored wetlands for the benefits of threatened and endangered species.
  

Site work included fence construction, sediment removal, drainage channel stabilization structures and sediment traps, designation of vegetation management zones, embankment repair, placement of water control structures, and installation of a wetland enhancement berm.

Site restoration work was recently completed, with funding for the site work and engineering provided by the LPSNRD and a 2012 Nebraska Environmental Trust grant to the City of Lincoln, and funds from the eastern saline wetlands project, said Malmstrom. Other support was provided through the Saline Wetlands Conservation Partnership, which consist of the City of Lincoln, LPSNRD, Nebraska Game and Parks Commission, and Pheasants Forever.

The eastern portion of the tract comprising 80 acres was purchased in 2009, said Mamlstrom. An addition of 50 acres on the western extent of the property was purchased in 2012. The Lower Platte South NRD is the area owner. The eastern extent of the area was used for years as a hunting club.

Particularly notable features of the site includes: saline wetland habitat, freshwater pond, two spring seeps, the confluence of Little Salt Creek and Salt Creek which forms the southern boundary, a small woodland area where bald eagle nests occur. In addition to a foot path and overlook, there is a roadway that can be hiked. The area parking lot is on Alvo Road, eastward from Northwest 40th Street.

This is a tally of the species that have been observed at the area from near the end of September through the first week of November, 2017. More than 35 checklists have been submitted to ebirds, enough to make the site a birding hotspot. The number of species seen during a particular visit have ranged from eight to 53, as well as 46 and 47. The ebird "species list was initially compiled during a time frame for the peak intersection of breeding marsh birds and migrating sparrows making for a hefty total right out of the gate," said Schwartz.

Figure showing management work done at the wetland area.

1. Greater White-fronted Goose
   
2. Canada Goose
   
3. Wood Duck
   
4. American Wigeon
   
5. Mallard
   
6. Blue-winged Teal
   
7. Northern Shoveler
   
8. Northern Pintail
   
9. Green-winged Teal
   
10. Ring-necked Pheasant
    
11. Wild Turkey
    
12. Northern Bobwhite
    
13. Pied-billed Grebe
    
14. Double-crested Cormorant
    
15. American Bittern
    
16. Great Blue Heron
    
17. Great Egret
    
18. Green Heron
    
19. Turkey Vulture
    
20. Bald Eagle
    
21. Northern Harrier
    
22. Sharp-shinned Hawk
    
23. Cooper's Hawk
    
24. Red-tailed Hawk
    
25. Rough-legged Hawk
    
26. American Kestrel
    
27. Merlin
    
28. Virginia Rail
    
29. Sora
    
30. American Coot
    
31. Killdeer
    
32. Spotted Sandpiper
    
33. Lesser Yellowlegs
    
34. Wilson's Snipe
    
35. Franklin's Gull
    
36. Ring-billed Gull
    
37. Herring Gull
    
38. Eurasian Collared-Dove
    
39. Mourning Dove
    
40. Great Horned Owl
    
41. Belted Kingfisher
    
42. Red-headed Woodpecker
    
43. Red-bellied Woodpecker
    
44. Downy Woodpecker
    
45. Hairy Woodpecker
    
46. Northern Flicker
    
47. Blue Jay
    
48. American Crow
    
49. Horned Lark
    

    Aerial view showing property boundary of the wetland area.

50. Barn Swallow
    
51. Black-capped Chickadee
    
52. White-breasted Nuthatch
    
53. House Wren
    
54. Sedge Wren
    
55. Marsh Wren
    
56. Ruby-crowned Kinglet
    
57. Eastern Bluebird
    
58. American Robin
    
59. Gray Catbird
    
60. European Starling
    
61. Orange-crowned Warbler
    
62. Nashville Warbler
    
63. Yellow-rumped Warbler
    
64. Palm Warbler
    
65. Common Yellowthroat
    
66. Spotted Towhee
    
67. American Tree Sparrow
    
68. Chipping Sparrow
    
69. Clay-colored Sparrow
    
70. Field Sparrow
    
71. Vesper Sparrow
    
72. Lark Sparrow
    
73. Savannah Sparrow
    
74. Grasshopper Sparrow
    
75. Henslow's Sparrow
    
76. Le Conte's Sparrow
    
77. Nelson's Sparrow
    
78. Fox Sparrow
    
79. Song Sparrow
    
80. Lincoln's Sparrow
    
81. Swamp Sparrow
    
82. White-throated Sparrow
    
83. Harris's Sparrow
    
84. White-crowned Sparrow
    
85. Dark-eyed Junco
    
86. Dickcissel
    
87. Red-winged Blackbird
    
88. Eastern Meadowlark
    
89. Western Meadowlark
    
90. Yellow-Headed Blackbird
    
91. Common Grackle
    
92. Brown-headed Cowbird
    
93. House Finch
    
94. Pine Siskin
    
95. American Goldfinch
    

There will certainly be more species observed as birders continue their visits. Especially valuable will be details on species present during the breeding season.

This area is an addition to other saline wetlands protected and which occur mostly northward of Lincoln.

"There are approximately 4,309 acres of Nebraska’s eastern saline wetlands remaining," Malmstrom said. "To date, approximately 1,590 acres of these wetlands are protected through conservation partner ownership and are open to the public."

Analysis of Winter Long-eared Owl Pellets

The Long-eared owl (Asio otus) is a permanent resident of Nebraska, but is seldom seen due to its nocturnal habits. Days are spent roosting in dense wooded cover with the Owls venturing out at night to hunt. Typically, for roosting and nesting Long-eared owls select woodlands adjacent to open grassy fields in which they hunt (Getz 1961). Although dispersed during the breeding season, these Owls often form wintering groups which utilize communal roosts.

With a large number of birds using an area continuously for a short period, or with a small number of owls using an area for an extended period, regurgitated pellets containing prey remains are concentrated at one location. The remains in the pellets provide a representative sample of prey consumed by the owls. Pellets were collected at two different sites utilized by wintering Long-eared Owls near Lincoln, Lancaster County, Nebraska.

Site 1 was located on private land southwest of Lincoln. Sixteen Long-eared Owls had been observed at this site during the 1980 Lincoln Christmas Bird Count (Cindy Cochran pers. comm.). On 13 February 1981 site 1 was visited to assess the roost habitat and to collect pellets. Six to 8 Long-eared Owls were flushed when they were approached to within 3 meters (m). The Owls were hesitant to fly when disturbed. This delay in flight provided an opportunity to note that a Short-eared Owl (A. flammeus) was also in the roost area. The group of Owls flew only a short distance to the east and landed back in the shelterbelt.

The roost of these Owls was a shelterbelt planted to Eastern Red Cedar (Juniperus virginianus). The two hectare (ha) shelterbelt is oriented east to west and is 50 m wide and 400 m long. It is comprised of 12 rows of planted cedars with an average diameter at breast height of 25 to 30 centimeters. Vegetation noted around the shelterbelt is deciduous trees such as Cottonwood (Populus deltoides), and a pasture consisting primarily of a cool season grass, Smooth Brome (Bromus inermis), and scattered cedar trees.

Site 2 was located 18 kilometers northwest of Lincoln at Branched Oak Wildlife Management Area. A pair of Long-eared Owls had been recorded as year-round residents in the area (Richard Manning pers. comm.). The apparent nesting and roost site is located within a 1 ha planted cedar grove 10 to 15 rows wide and 20 to 25 trees deep. The branches of the trees within the grove are dead to height of about 1.7 to 2.5 m which makes access and movement within the grove difficult. Immediately surrounding the wooded area is a planting of Smooth Sumac (Rhus glabra), several Ponderosa Pine (Pinus ponderosa), poplars (Populus sp.), brushy plants including Wild Plum (Prunus sp.) and Rose (Rosa sp.), and large areas of brome. East of the grove is another brushy area, 75-100 m long, comprised of typical plant species invading a grassland. The grove is located within 150 m of Branched Oak Lake.

Pellet Analysis

Pellets were collected from site 1 on 13 February 1981 and site 2 on 14 March 1981. All pellet material observed, including complete pellets and weathered incomplete pellets and other debris, was collected. The pellets were then carefully picked apart and the contents identified. Mammal remains were identified with the aid of a cranium key (Glass 1951) and by comparison with representative skulls in the mammal collection at the University of Nebraska-Omaha (UNO). Bird remains were identified by skull remnants and by complete or partially complete bills. Each individual cranium/skull and pair of dentary bones were considered as one occurrence of the prey animal. The dentary bones were paired with a similar species skull and were not counted twice. Remaining skulls without corresponding dentary bones and paired dentary bones were each considered as an occurrence of the prey animal.

Prey item biomass was determined by utilizing an average body weight for the species recorded. Average body weights from mammals are from Schwartz (1981). Specific avian masses are from Amadon (1943) and other sources. Representative weight for a group of birds, i.e. Fringillidae, is from Marti (1974).

Results and Discussion

A total of 465 pellets and 236 incomplete pellets or debris pieces were collected from the two locations. Pellet contents included at least 10 mammal and 3 bird species (Table 1). Voles, genus Microtus, were the most common prey item that occurred and comprised almost half of the total biomass consumed (Table 2).

Table 1. Vertebrate remains in Long-eared Owl pellets from two sites near Lincoln, Lancaster County, Nebraska
	Prey Items				Total Biomass
	Number		Percent		Grams		Percent
Species	Site 1	Site 2	Site 1	Site 2	Site 1	Site 2	Site 1	Site 2
Least Shrew (Cryptotis parva)	6	10	2.2	2.5	21	35	T	T
Short-tailed Shrew (Blarina brevicauda)	-	17	-	4.3	-	357	-	3
White-footed/Deer Mouse (Peromyscus spp.) (a)	83	76	29.9	19.2	1,577	1,444	21	12
Meadow Vole (Microtus pennsylvanicus)	65	167	23.4	42.2	2,730	7,014	36	56
Prairie Vole (Microtus ochrogaster)	43	26	15.5	6.6	1,655	1,001	22	8
Vole spp. (Meadow or Prairie, #2 upper cheek tooth missing, so not determinate)	-	11	-	2.8	-	456	-	4
Harvest Mouse (Rethrodontomys spp.) (b)	75	67	27.0	16.9	1,425	737	19	6
House Mouse (Mus musculus)	4	-	1.4	-	84	-	1	-
Eastern Cottontail (Sylvilagus floridanus)	-	1	-	0.2	-	750*	-	1
House Sparrow (Passer domesticus)	-	4	-	1.0	-	100	-	T
Red-winged Blackbird (Agelaius phoeniceus)	-	5	-	1.3	-	275	-	2
Cardinal (Cardinalis cardinalis)	1	-	0.3	-	44	-	1	-
Unidentified Passeriformes (c)	1	4	0.3	1.0	30	120	T	1
Unidentified Fringillidae (c)	-	8	-	2.0	-	240	-	2
	278	396	100.0	100.0	7,566	12,529	100	100
(a) Either White-footed (P. leucopus) or Deer (P. maniculatus) Mouse, extreme fragmentation prohibits specific identification. (b) Probably Western (R. megalotus) as Plains (R. montanus) Harvest Mouse is locally uncommon. Skulls greatly fragmented. (c) Identified by bill remains only. * Average mass x .75 = consumed biomass (Grear and Gilstrap 1970). T Trace amounts of less than 1%.

Pellets collected from site 2, Branched Oak Lake, contained 4 species not recorded at site 1. These were the Short-tailed Shrew (Blarina brevicauda), Eastern Cottontail (Sylvilagus floridanus), House Sparrow (Passer domesticus), and Red-winged Blackbird (Agelaius phoeniceus). Pellets from the cedar shelterbelt/pasture area of site 1 contained the House Mouse (Mus musculus) and Northern Cardinal (Cardinalis cardinalis) which were not recorded from the lake site. The average mass of a prey item was 29.8 grams. This weight most closely approximates the mass of the small rodents which were the most frequently consumed prey items found in the pellets. (Tables 1 through 3 provide a complete analysis of prey composition and frequency).

Table 2. Combined contents of Long-eared Owl pellets from two sites near Lincoln.
Prey Group	Prey Items		Biomass
	Number	Percent	Grams	Percent
Least Shrew (Cryptotis parva)	16	2.4	56	0.3
Short-tailed Shrew (Blarina brevicauda)	17	2.5	357	1.8
White-footed/Deer Mouse (Peromyscus spp.)	159	23.6	3,021	15.0
Voles (Microtus spp.)	312	46.3	12,856	64.0
Harvest Mouse (Reithrodontomys spp.)	142	21.1	2,162	10.8
House Mouse (Mus musculus)	4	0.6	84	0.4
Eastern Cottontail (Sylvilagus floridanus)	1	0.1	750	3.7
Birds	23	3.4	809	4.0
	674	100.0	20,095	100.0

Table 3. Number of prey items (i.e., individual animals) recorded per pellet analyzed, from Long-eared Owls from two sites near Lincoln.
Items per Pellet	Number of Pellets			Percent
	Site 1	Site 2	Total
0	0	43	43	9.3
1	156	186	342	73.5
2	37	28	65	14.0
3	5	3	8	1.7
4	2	4	6	1.3
5	0	1	1	0.2
	200	265	465	100.0

A comparison of the pellet contents of Long-eared Owls from several states is given in Table 4. Data from Michigan (Geis 1952), Minnesota (Christenson and Fuller 1975), Indiana (Kirkpatrick and Conway 1947), Illinois (Cahn and Kemp 1930, Birkenholtz 1958) and Ohio (Randle and Austing 1952) are given for comparative purposes. Although results obviously vary from location to location, an interesting difference of the Nebraska data presented is the relatively high , combined percentage of White-footed/Deer Mouse spp. and Harvest Mouse spp. Only Illinois had a higher percent composition of White-footed/Deer Mouse spp. Harvest Mice occurrence in Nebraska was almost 20 percentage points higher, in relation to total prey consumed, than values for the two other sites where they were recorded. The percentage of total avian prey items is notably consistent around 2-3% for all of the studies cited.

Table 4. A comparison of contents of Long-eared Owl pellets from six states, in percentage of prey items.
Prey Group	Michigan	Minnesota	Indiana	Illinois* A	Illinois* B	Ohio*	Nebraska*
Least Shrew (Cryptotis parva)	-	-	7.6	-	20.8	10.4	2.4
Short-tailed Shrew (Blarina brevicauda)	1.4	4.4	1.0	3.5	-	10.2	2.5
White-footed/Deer Mouse (Peromyscus spp.)	10.0	7.7	10.3	40.7	13.1	5.3	23.5
Voles (Microtus spp.)	84.3	81.3	75.9	29.2	47.8	62.9	46.3
Harvest Mouse (Reithrodontomys spp.)	-	2.2	-	-	-	0.5	21.2
House Mouse (Mus musculus)	-	-	-	23.0	11.1	3.2	.6
Birds	2.6	3.3	2.8	2.7	1.5	3.3	3.4
Other	1.7	1.1	2.4	0.9	5.7	4.2	0.1
	100.0	100.0	100.0	100.0	100.0	100.0	100.0
* Pellets were collected from wintering birds A Cahn and Kemp 1930; B Birkenholtz 1958.

Other variations in pellet contents represent many possible environmental differences. This could include differences in individual owl prey selection, prey type occurrence and density, and the physical characteristics of the hunting territory. Additional factors could include the presence of competing predatory birds and mammals which might affect the Owls behavior or possibly affect prey composition in the diet.

The results of this study indicate that Long-eared Owls appear to be indiscriminate feeders that prey on a diverse group of suitably sized animals that are available in the area of the roost.

Literature Cited:

Amadon, D. 1943. Bird weights and egg weights. Auk 60: 221-234.

Birkenholtz , D. 1958. Notes on a wintering flock of long-eared owls. Illinois Academy of Science Transactions 51: 83-86.

Cahn, A.R. and J.R. Kemp, 1930. On the food of certain owls in east-central Illinois. Auk 47: 323-328.

Christenson, G. and M.R. Fuller. 1975. Food habits of two long-eared owl families in east-central Minnesota. Loon 47: 58-61.

Geis, A.D. 1952. Winter food habits of a pair of long-eared owls. Jack-Pine Warbler 30: 93.

Getz, L.L. 1961.Hunting areas of the long-eared owl. Wilson Bulletin 73: 79-82.

Glass, B.P. 1951. A key to the skulls of North American mammals. Oklahoma University. Stillwater, Oklahoma. 53 pp.

Greer, J.K. and R.L. Gilstrap. 1970. Vertebrate remains in barn owl pellets. Bulletin of the Oklahoma Ornithological Society 3: 25-29.

Kirkpatrick, C.M. and C.H. Conaway. 1947. The winter food of some Indiana owls. American Midland Naturalist 38: 755-766.

Marti, C.D. 1974. Feeding ecology of four sympatric owls. Condor 76: 45-61.

Randle, W. and R. Austing. 1952. Ecological notes on long-eared and saw-whet owls in southwestern Ohio. Ecology 33: 422-426.

Schwartz, C.W. and E.R. Schwartz. 1981. The wild mammals of Missouri. University of Missouri Press, Columbia. 356 pp.

Jim Ducey and John Kirby. September 1983. An analysis of winter long-eared owl pellets from Lancaster County, Nebraska. Nebraska Bird Review 51(3): 79-82.

Biological Features of Saline Wetlands in Lancaster County, Nebraska

1987. Biological features of saline wetlands in Lancaster County, Nebraska. Transactions of the Nebraska Academy of Sciences 15: 5-14.

The natural history of saline wetland areas near Lincoln, Lancaster County, was evaluated. Most remaining salt marshes occur on saline soils along Little Salt Creek. Numerous plant species of saline soils occur that are limited to this part of the State. The avifauna is diverse, with 67 species recorded during the breeding season, 47 of them breeding. Because wetlands are limited in distribution in Nebraska, key biological elements, potential threats to the areas, and management considerations are discussed.

Introduction

Salt marshes occur in eastern Nebraska only near Lincoln, on lowlands in the Salt Creek Basin. They are very limited compared to other plant community types in Nebraska, and have been considered an endangered habitat (Kaul, 1975). A few small salt marshes are found here and there in the Sandhills and North Platte River Valley.

The Lancaster County salt marshes were once extensive on lowlands along the creeks, but changes in land use through the decades have drastically reduced them. The remaining sites are so limited that additional disturbances could destroy entirely a representative plant community.

There is need for an active conservation effort to identify, evaluate, and protect the remaining salt marshes. Conservation of these sites would protect:

1. unique salt-marsh plant communities that are the result of prehistoric conditions on the Great Plains.

2. salt-marsh vegetation important in ecological research.

3. wetland habitat used by an impressive variety of native wildlife, especially birds.

4. natural lands and the value they have for environmental education and outdoor recreation.

5. native prairie land.

The saline wetlands result from groundwater seeping to the surface from the Dakota Formation (Shirk, 1924). The salt was initially formed millions of years earlier when a vast inland sea covered central North America. White alkaline deposits can often be found on the ground in some of these wetlands.

I have compiled information on these areas to identify their biological features that should be conserved.

Methods

I determined the location of some wetlands from references listing areas visited by bird watchers, and I found other sites by using U.S. Geological Survey topographic maps. I also used aerial photographs to assess the extent of marshland along Little Salt Creek. I made nearly 60 visits since 1980 to evaluate the avifauna in the North 27th Street area, and I visited the over sites periodically from 1984 through 1986.

Other biologists provided information from their field work, including persons from the University of Nebraska-Lincoln, the University of Chicago, the Nebraska Game and Parks Commission, and bird watchers from the Wachiska Audubon Society. Popular articles also have information on the history of saline marshes near Lincoln (Cunningham, 1985; Ducey, 1985, 1987).

Soils

The saline soils belong to the Salmo Series of deep, poorly drained bottomland soils of low permeability (Soil Conservation Service, 1980). They formed on silty alluvium that is slightly to moderately affected with soluble salts. This soil type commonly occurs near creeks, intermittent lakes, and marshes, and is usually only briefly flooded (Table I). Salt-marsh soils in general are highly saline and have a high water-holding capacity (Ungar, 1969).

Three soils are classified in the Salmo Series:

1. Salmo silt loam, Sa, is a nearly level, poorly drained soil of bottomlands, and is occasionally flooded. Shallow depressions and meandering drains are common.

2. Salmo silty-clay loam, Sb, is channeled with ~2% slope. It is a nearly level, poorly drained soil found frequently on bottomlands. Shallow depressions and meandering drains are common. Prairie cordgrass is the commonest plant, but overgrazed areas are invaded by inland saltgrass.

3. Salmo silty-clay loam, Sc, ~2% slope. It is located on poorly drained bottomland that is occasionally flooded.

Table I. Characteristics of Salmo Series soils in Lancaster County.
				Flooding		Salinity
Soil Type	Range Type	Acres	Percent	Duration	Months	Mmhos/cm
Sa	Saline lowland	900	0.2	Brief	Mar-Oct	4-16
Sb	Saline subirrigated	2,300	0.4	Brief	Mar-Oct	4-16
Sc	Saline subirrigated	2,480	0.5	Brief	Mar-Oct	4-16

Salt-Marsh Vegetation

Although there have been no complete botanical surveys, herbarium specimens, literature notes, and field observations document most plant species of the saline soils. Several species are abundant, but others occur in just few of the wetlands. The growing conditions are so variable that the flora varies from site to site. Table II lists representative species in the sites.

A variety of terrestrial and aquatic plant communities have been identified at some of these saline wetlands (Ungar, 1969), and their distribution, as well as that of other habitats typical of southeastern Nebraska, is summarized in Table III for most of the salt-marsh areas visited. (Scientific names of plants are given in Table II.)

Subtle differences in topography, soils, and drainage influence the vegetation and create, in some places, many different plant associations in small areas. The most important factor affecting plant occurrence and distribution in the salt marshes is the osmotic concentration of the soil solution (Ungar, 1969). A reduction in soil salinity results in an increase in cover or species numbers, but not necessarily both. Sea blite is the most salt-tolerant species, and is usually the first to invade barren salt flats; where salinity is reduced along the border of saline areas, numerous prairie species invade (Ungar, 1969).

Because the distribution of salt-marsh plants (halophytes) fluctuates with precipitation and temperature within and among the sites (Shirk, 1924), an extensive area of saline soils is needed to ensure that suitable habitat remains somewhere.

Table II. Representative flora noted at saline wetlands near Lincoln, Lancaster County. Additional species would be expected with a more comprehensive survey.
	Locality
PLANT SPECIES Common Name and Scientific Name	Airport Flats	Capitol Beach	R.R. Yards	Lagoon Park	North 40th	North 27th	North L. Salt
Alkali bluegrass. Poa juncifolia Scribn.	—	—	—	—	X	—	—
Alleghany monkey-flower. Mimulus ringers L.	—	—	—	X	—	—	—
Annual iva. Iva ciliata Willd.	—	X	X	—	X	X	—
Bearded sprangletop. Leptochloafascicularis (Lam.) Gray	—	—	—	X	—	—	—
Bluestem. Andropogon spp.	—	—	—	—	—	X	X
Blue grama. Bouteloua gracilis (H.B.K.) Griffiths	—	—	—	X	—	—	X
Buffalo grass. Buchloe dactyloides (Nutt.) Engelm.	—	—	—	X	—	—	—
Cattail. Typha spp.	—	X	—	X	X	X	X
Common reed. Phragmites australis (Cov.) Trin.	—	—	X	—	—	—	—
Cottonwood. Populus sp.	—	—	—	—	X	X	—
Ditchgrass. Ruppia marifima L.	—	—	—	—	—	X	—
Elm. Ulmus sp.	—	—	—	—	—	X	—
Fern flatsedge. Cyperus filiculmis Vahl	—	—	—	—	—	—	X
Gayfeather. Liatris sp.	—	—	—	—	—	—	X
Goldenrod. Solidago spp.	—	—	—	—	—	X	—
Hackberry. Celtis occidentalis L.	—	—	—	—	—	X	—
Large alfalfa dodder. Cuscuta indecora Chois.	—	—	—	X	—	—	—
Ludwigia. Ludwigia peploides (H.B.K.) Raven	—	—	—	X	—	—	—
Plains bluegrass. Poa arida Vasey	—	—	—	—	—	X	—
Prairie cordgrass. Spanina pectinata Link	—	—	—	—	X	—	X
Prairie cupgrass. Eriochloa contracta Hitchc	—	—	—	X	—	—	—
Prickly pear. Opuntia sp.	—	—	—	X	—	—	—
Redroot Cyperus. Cyperus erythrorhizas Muhl	—	—	—	X	—	—	—
Redscale. Atriplex rosea L.	X	X	—	X	—	—	—
Sago pondweed. Potamogeton pectinatus L.	—	—	—	—	—	X	—
Salt grass. Distichlis spicata L.	X	X	—	X	X	X	X
Saltmarsh aster. Aster subulatus var. ligulatus Shinners	—	—	—	—	—	X	—
Saltwort. Salicornia rubra L.	X	X	—	—	X	X	X
Sea blite. Suaeda depressa (Purch) Wats.	X	X	—	X	X	—	—
Sedge. Carex spp.	—	X	—	X	X	X	X
Sideoats grama. Bouteloua curtipendula (Michx.) Torr.	—	—	—	—	—	—	X
Seaside heliotrope. Heliotropium curassavicum L.	—	—	—	X	—	—	—
Seaside saltgrass. Distichlis spicata (L.) Greene	X	X	X	X	X	X	X
Slender flatsedge. Cyperus ferruginescens Boeckl.	—	—	—	X	—	—	—
Spearscale. Atriplex spp.	X	X	—	—	—	X	—
Spikesedge. Eleocharis spp.	X	—	—	—	X	X	X
Swamp milkweed. Asclepias incarnata L.	—	—	—	X	—	—	—
Switchgrass. Panicum virgatum L.	—	—	—	—	—	—	X
Texas dropseed. Sporobolus texanus Vasey	—	—	—	—	—	X	—
Tooth-cup. Ammannia coccinea R.H.B.	—	—	—	X	—	—	—
Westem snowberry. Symphoricarpos albus L. Blake	—	—	X	—	—	X	—
Westem wheatgrass. Agropyron smithii Rydb.	—	—	—	X	—	—	—
Willow. Salix spp.	X	X	—	—	X	—	—
Yerba-de-tajo. Ecliota alba (L.) Hassk.	—	—	—	X	—	—	—

 

Table III. Summary of habitat types of saline wetlands near Lincoln, Lancaster, County.
	Locality
Habitat Type	Airport Flats	Capitol Beach	R.R. Yards	Lagoon Park	North 40th	North 27th	North L. Salt
Alkaline Meadow	X	—	X	X	—	X	X
Cattail Marsh	—	X	—	X	X	X	X
Cordgrass Meadow	—	—	—	—	X	—	X
Lowland Woods	X	X	—	—	—	X	X
Mud Flats	X	—	—	—	X	X	X
Native Prairie	—	—	—	X	—	X	X
Open Water-Lake	—	X	—	X	X	X	X
Riparian Woods	—	—	—	—	—	X	—
Sedge Marsh	—	—	—	—	—	X	—
Shrubland	—	—	—	—	—	X	—
Weedy Lowland	—	—	—	—	—	X	—

Diatoms

Diatoms specific to saline environments are known from these salt marshes. Elmore (1921) collected five species near Little Salt Greek at the now-vanished settlement of Arbor: Synedra fasciculata, Navicula crucicula, Entomoneis alata, Nitzschia hungarica, and N. acicularis.

Avifauna

Bird enthusiasts have been keeping records of salt-marsh bird life for nearly 100 years (Hunter, 1900, and about 30 other references in publications of the Nebraska Ornithologists' Union). The open water, marshes, meadows, prairie, and woods provide habitat for a large and diverse avifauna. More than 230 breeding and migrating species have been recorded in the last 90 years (Ducey, 1985). Nomenclature used here is from American Ornithologists' Union (1983), and scientific names are given in Table IV.

Perhaps the most interesting part of the avifauna is the diversity of non-breeding shore and water birds. Historic observations of migratory species include white-faced ibis, snowy egret, lesser golden plover, Hudsonian godwit, black-bellied plover, snowy plover, mountain plover, red knot, and long-billed curlew. Recent records include sightings of the black rail, king rail, black-necked stilt, and black-legged kittiwake (Ducey, unpublished manuscript).

Notable breeding birds recorded in the early 1900's included snowy egret (Eiche, 1901), piping plover (Pickwell, 1925), and scissor-tailed flycatcher (Dawson, unpublished notes). Potential breeders were least tern and sedge wren.

Among the 67 species noted in recent years are some of very limited breeding occurrence in the State (Table IV): least bittern, common moorhen, king rail, and great-tailed grackle. Waterfowl, shore birds, and icterids are the largest groups.

The habitat diversity of the saline wetlands is apparent in the breeding avifauna. Each area has certain vegetative communities needed by particular species. At the North Little Salt site, the wetland meadows are used by bobolinks. Federation Marsh, with its bordering woodlands, has five species not noted elsewhere: green-backed heron, green-winged teal, northern rough-winged swallow, marsh wren, and northern cardinal. A limited amount of prairie at the North Little Salt and North 40th Street sites is used by the grasshopper sparrow.

Breeding species at Capitol Beach that have not been found breeding in the other sites are northern shoveler, ruddy duck, king rail, Virginia rail, rock dove, tree swallow, and blue grosbeak (Table IV). The rock dove indicates the proximity of the area to the urban nesting sites that these birds use.

TABLE IV. Species and location of breeding season occurrence of birds associated with Salt Creek wetlands. Species that have had nesting confirmed are marked with an asterisk (*). These are combined observations of J. Ducey (1980-83, 1985, 1986) for areas along Little Salt Creek, W. Garthright (1983-85) primarily for Capitol Beach and Federation Marsh, D. Showen at Lagoon Park (1984-86), and P. Johnsgard for [student surveys at] Lagoon Park and North 27th (1985-87).
	Location
Bird Species	Capitol Beach	Lagoon Park	North 40th	North 27th	North L. Salt
American coot. Fulica americana Gmelin	X*	X	—	X*	—
American goldfimch. Carduelis tristus (Linnaeus).	X*	X	X	X	—
American robin. Turdus migratorius Linnaeus	X*	X	X*	X*	X
Barn swallow. Hirundo rustica Linnaeus	—	—	X	X*	X
Bell's vireo. Vireo bellii Audubon	X*	—	—	X	—
Belted kingfisher. Ceryle alycon (Linnaeus)	—	X	—	X	—
Black-billed cuckoo. Coccyzus erythropthalmus (Wilson)	X*	—	—	—	—
Black-capped chickadee. Parus atricapillus Linnaeus	—	—	—	X	—
Blue grosbeak. Guiraca caerulea (Linnaeus)	X	—	—	—	—
Blue jay. Cyanocitta cristata (Linnaeus)	—	X	X	X	—
Blue-winged teal. Anas discors Linnaeus	X*	X*	—	X*	X
Bobolink. Dolichonyx oryzivorus (Linnaeus)	—	—	—	—	X
Brown thrasher. Toxostoma rufum (Linnaeus)	—	—	X	X*	X
Brown-headed cowbird. Molothrus ater (Boddaert)	X*	X	X	X*	X
Canada goose. Branta canadensis (Linnaeus)	—	X	—	X*	—
Common grackle. Quiscalus quiscula (Linnaeus)	—	X	X	X	X
Common moorhen. Gallinula chloropus (Linnaeus)	X*	—	—	X	—
Common yellowthroat. Geothlypis trichas (Linnaeus)	—	X	X	X	X
Dickcissel. Spiza americana (Gmelin)	X*	—	X	X	X
Downy woodpecker. Picoides pubescens (Linnaeus)	—	X	—	—	—
Eastern kingbird. Tyrannus tyrannus (Linnaeus)	X*	X	X	X*	X
Eastern meadowlark. Sturnella magna (Linnaeus)	—	—	—	X	—
European starling. Sturnus vulgaris Linnaeus	—	X	—	X*	—
Field sparrow. Spizella pusilla (Wilson)	—	—	—	X	—
Grasshopper sparrow. Ammodramus savannarum (Gmelin)	—	—	X	—	X
Gray catbird. Dumetella carolinensis (Linnaeus)	—	X	—	X*	—
Great horned owl. Bubo virginianus (Gmelin)	—	X	—	X*	—
Great-tailed grackle. Quiscalus mexicanus (Gmelin)	X*	X	X	X*	—
Green-backed heron. Butorides striatus (Linnaeus)	—	—	—	X	—
Green-winged teal. Anas crecca Linnaeus	—	—	—	X	—
House sparrow. Passer domesticus (Linnaeus)	X*	X*	—	X*	—
House wren. Troglodytes aedon Vieillot	—	—	—	X*	—
Killdeer. Charadrius vociferus Linnaeus	X*	X*	X*	X	X
King rail. Rallus elegans Audubon	X	—	—	—	—
Least bittern. Ixobrychus exilis (Gmelin)	X*	—	—	X*	—
Mallard. Anas platyrhynchos Linnaeus	X*	X*	—	X*	—
Marsh wren. Cistothorus palustris (Wilson)	—	—	—	X	—
Mourning dove. Zenaida macroura (Linnaeus)	X*	X*	—	X*	X*
Northern bobwhite. Colinus virginianus (Linnaeus)	—	—	—	X*	X
Northern cardinal. Cardinalis cardinalis (Linnaeus)	—	—	—	X	—
Northern flicker. Colaptes auratus (Linnaeus)	—	—	—	X*	X
Northern oriole. Icterus galbula (Linnaeus)	—	X	X	—	—
N. Rough-winged swallow. Stelgidopteryx serripennis (Audubon)	—	—	—	X*	—
Northern shoveler. Anas clypeata Linnaeus	X*	X	—	—	—
Orchard oriole. Icterus spurius (Linnaeus)	X*	X	—	X*	X
Pied-billed grebe. Podilymbus podiceps (Linnaeus)	X*	X	—	X*	—
Red-headed woodpecker. Melanerpes erythrocephalus (Linnaeus)	—	X	—	X*	—
Red-tailed hawk. Buteo jamaicensis (Gmelin)	—	X	—	X*	X
Red-winged blackbird. Agelaius phoeniceus (Linnaeus)	X*	X*	X	X*	X*
Ring-necked pheasant. Phasianus colchicus Linnaeus	—	X*	X	X	X
Rock dove. Columba livia Gmelin	X*	—	—	—	—
Rose-breasted grosbeak. Pheucticus ludovicianus (Linnaeus)	—	X	—	X	—
Ruddy duck. Oxyura jamaicensis (Gmelin)	X*	X	—	—	—
Sedge wren. Cistothorus platensis (Latham)	—	—	—	X	—
Song sparrow. Melospiza melodia (Wilson)	X*	—	X	X	—
Sora. Porzana carolina (Linnaeus)	—	X	—	X*	X
Spotted sandpiper. Actitis macularia (Linnaeus)	X*	—	X	—	—
Tree swallow. Tachycineta bicolor (Vieillot)	X*	—	—	—	—
Virginia rail. Rallus limicola Vieillot	X*	X	—	—	—
Warbling Vireo. Vireo gilvus (Vieillot)	X	—	—	X	—
Westem Kingbird. Tyrannus verticalis Say	X*	X	—	—	—
Westem Meadowlark. Sturnella neglecta Audubon	—	—	X	X	X
Willow Flycatcher. Empidonax traillii (Audubon)	—	—	X	X	—
Wood Duck. Aix sponsa (Linnaeus)	X	—	—	X*	—
Yellow Warbler. Dendroica petechia (Linnaeus)	X*	X	—	X	—
Yellow-billed Cuckoo. Coccyzas americanus (Linnaeus)	X*	X	—	X	—
Yellow-headed Blackbird. Xanthocephalus xanthocephalus (Bonaparte)	X*	—	—	X*	—
Number of species with: Confirmed nesting	30	7	2	29	3
Possible or probable nesting	4	28	18	24	18
Total	34	35	20	53	21

Invertebrates

Another notable biotic feature of the saline marshes is a mosquito, Aedes sollicitans (Walker), that has been collected in Nebraska only here (Lunt and Rapp, 1981). A beetle of very limited occurrence in Nebraska has been observed at the saline flat near the Lincoln airport (1987, B. Ratcliffe, personal communication).

Wetland Locations and Characteristics

Saline wetland soils are less than 1% of the land area in Lancaster County (Soil Conservation Service, 1980), but they have very diverse wildlife habitats. Relatively bare, open flats with true salt-marsh halophytes are extensive at some sites, but others have extensive growths of cattails and sedges. Cordgrass meadows survive on some lowland areas along creeks, and on the fragments of untilled upland there is woodland and prairie grassland.

Below is a listing of saline wetlands along Salt Creek and Little Salt Creek, including legal and general descriptions and comments on their biota and present condition.

1. Airport Flats

N 1/2 of the NW l/4 of Section 21, T10N, R6E.

Soils: Sa, Sb

The area is mostly saline meadow in what was once known as the Salt Basin, and is now known as Capitol Beach. Interstate Highway 80 separates this tract from lakeside property along Capitol Beach (Salt) Lake, and therefore the area has no ready access. Erosion could become a problem if repair of the berm on the east side of the Flats is not made. The runways of the Lincoln Airport are adjacent, and should prevent development of this area.

2. Capitol Beach (Salt Lake)

NE 1/2 of Section 21 and NW 1/4 of Section 22, T10N, R6E.

Soils: Sb and Sc to the east of the lake

This was the historic Salt Basin. A dam built in the 1890's increased the depth and extent of standing water (Barbour, 1895). Bird watchers have enjoyed visiting this spot for decades because of the unusual avifauna (Ducey, 1985). Small, marshy areas, including semi-permanent wetland basins, remain east of the lake along an intermittent stream that flows into Salt Creek. More than 30 species of birds have been noted during the breeding season, and nearly all are confirmed nesters. Eight are species not recorded at other salt-marsh localities: northern shoveler, ruddy duck, king rail, Virginia rail, black-billed cuckoo, western kingbird, tree swallow, and blue grosbeak. The king rail and common moorhen are especially notable.

Most of the Capitol Beach wetland has been destroyed by residential and industrial development. The remaining small areas are threatened by further industrial encroachment, and camping by transients and dumping of debris further degrade the value of the area for wildlife.

3. Burlington Northern Railroad Yards

N l/2 of Sections 28 and 29, T1ON, ROE.

Soil: Sc

This area, also on the west side of Lincoln, was an area where several saline plant communities once grew in soils of different salinity (Shirk, 1924). It has been mostly destroyed since then by development of railroad facilities such as switching yards and parking lots, and there is no valuable saline area remaining. Only very small, heavily disturbed areas remain. Salt grass and annual iva are still present in a few places, as are seablite, saltgrass, and spearscale.

Along Middle Creek in the southern half of section 27, to the south of the railroad yards, is a sizeable tract with wetland basins, salt flats, and lowland grassland with scattered trees. This area is being disrupted by construction of the K and L street extensions, and a park will be constructed in the remaining area.

4. Oak Lake

SW 1/4 of Section 14, T1ON, ROE.

Soils: non-saline

Formerly there were two lakes, but one was bisected by Interstate Highway 180, and now there are three. They contain some plants of saline waters, most notably ditch-grass.

5. Lagoon Park

SW 1/4 of Section 32, T11N, R7E.

Soils: Sb, Sc

The saline habitat is a weed-free saline meadow southeast of the west lake. Saltgrass is predominant, with many other unusual species more typical of western grasslands: rough dropseed, western wheatgrass, blue grama, and buffalo-grass. Cordgrass grows along the edge of the lake. Prickly-pear cactus occurs here, its only known occurrence in saline communities in the Lincoln area.

The permanent deep-water habitat has a good number of aquatic plant species, including Ludwigia peploides, which has been collected here and only at one other site in the State. Other species are redscale, seaside heliotrope, swamp milkweed, yerba-de-tajo, and numerous sedges. A cattail marsh is at the northern edge of the east lake.

Burning, which improves grasslands, was done by the Wachiska Audubon Society in 1987. The area will be developed as a city park when the adjacent city landfill is abandoned.

The best saline habitat is immediately adjacent to the city landfill. A fence separates the two areas, but trash blows into the meadow. A more serious threat would be earth-moving that will be needed to grade the surface of the landfill. Such activity would destroy the small saline meadow. Drainage from mounds of earth-covered trash could influence the growing conditions of the meadow. The Lincoln Parks and Recreation Department recognizes the value of this area and plans to designate the lagoon area for natural history uses.

Improvement of this area would provide an anchor site for additional protection efforts to the north and west along Little Salt Creek. Drainage work by the City of Lincoln has diverted the constant flow of water that once drained into the lake, and since then there has been greater fluctuation in water levels. The permanent results of this change in the water regime are uncertain.

6. North 40th Street

NW 1/4 of Section 32, T11N, R7E; NE l/4 and NE 1/4 of the NW l/4 of Section 31, and W 1/2 of SE 1/4 of Section 30.

Soils: Sb, Sc

The second area (Section 31) has an excellent example of cordgrass meadow. A small cattail marsh continues to the east, and joins with the first site given above. The meadow continues along the flats adjacent to the creek, but to the west it has been affected by agricultural plowing, which was unsuccessful, and the potential for re-establishment of cordgrass appears good. The property is also seriously disturbed by overgrazing. Some areas of the saline flats have an extensive growth of western wheatgrass, kochia, and wild barley.

The best example of saline flats occurs in Section 30. The flat land has open areas of mud and clumps of vegetation. The typical salt marsh indicator plants—saltwort, sea blite, spearscale, annual iva—grow among areas of alkali bluegrass. To the north is a growth of sedges that grades into a small cattail marsh. This site has fewer weeds than any other meadows visited, has the best remaining examples of salt-flat vegetation, is an excellent place to observe shorebirds, and appears to be the least disturbed of any of the meadows visited.

The area is threatened by erosion and periodic agricultural disturbance. Control of erosion, removal of cattle, and periodic burning would improve chances of survival of the plants. A threat to the north is a change in drainage. The flats are dissected by ditches formed by runoff, and erosion will continue to deepen them. This could change the soil-water characteristics, and an increase in runoff would drain the small, shallow basins that retain water. The landowner to the south closed a dike to reduce erosion on his property, causing the southern half of the area in Section 30 to be flooded through spring, but it is usually dry by early summer.

There are extensive saline flats directly to the west, across the railroad from the site described above, in the N 2/3 of the W 1/2 of Section 31, T11N, R6E. The soils there are Sa, Sb, and Sc. These open flats have been used for agriculture, especially for grazing cable, and a portion was plowed in 1985 for cropland.

7. North 27th Street

W l/2 of the SW 1/4 Section 19, T11N, R7E.

Soils: Sa, Sb, Sc

7a. Arbor Lake

On the east side of the road is an extensive area of saline meadow and an open, slightly vegetated mud flat. The meadow has alkali bluegrass, saltwort, sea blite, spearscale, and annual iva. Saltmarsh aster occurs here and at nearby saline sites, its only known locations in the State. Texas dropseed also is found here and nearby, some of the few sites it is known from in the State. Bearded sprangletop is common in the State but the population here has different floral characteristics that make the plants especially interesting (D. Sutherland, personal communication).

Disturbance in this area appears to be limited to erosion, which is beginning to cut into the flats on the south end. The water-retention dike along the south property line has a hole, and the runoff and erosion rates have increased.

Shorebirds are numerous when standing water is present, especially during migration. Killdeer and red-winged blackbirds are the primary breeding species on the flats and limited emergent vegetation.

7b. Federation Marsh

On the west side of the road is a very diverse area of woodland, grassland, and wetland, but there is little saline wetland. The only example is saltgrass in a saline meadow; bluestem and cordgrass also occur. There is also open water and cattail-sedge marsh. Seaside heliotrope was collected at the edge of one basin, on bare mud during low water, the only record of this western species from eastern Nebraska.

Water is usually pumped from adjacent Little Salt Creek each year to raise water levels and improve conditions for hunting of waterfowl. This influx of freshwater may influence the salinity of the wetlands, reducing growth of salt-marsh plants, but the water attracts a large diversity of migratory and breeding birds.

Most of the flats along the creeks have been heavily disturbed, and apparently an attempt was made to cultivate the property early in the century, according to the landowner. As a result, the predominant plants are annuals, including ragweeds, sunflowers, thistles, and Japanese brome, but there are some native species where the ground is wet.

Another area of grassland occurs on upland on the eastern edge of the site. There are native plants, including bluestem, gayfeather, and wild rose. This prairie is very disturbed and would require extensive rejuvenation. There are two areas of successional grassland. The upland site on the western edge is predominantly rough dropseed and little and big bluestems. The shrubby western snowberry is invading the area. On low land along the creek the successional area is mostly Kentucky bluegrass and smooth brome. Woody plants include ash, locust, hackberry, elm, and snowberry.

Remnant riparian woodland occurs along the eastern and western edges of the site. The grove on the east side is almost entirely of elm, with a few cottonwoods along the edge of the basin. The woodland on the west side of the basin has thickets of American plum, ash, locust, mulberry, willows, snowberry, and juniper. They are very dense in places and provide extensive cover for wildlife. There is a replanted warm-season grassland west of the wetland area, in which big bluestem and Indiangrass are planted.

This site has the highest diversity of breeding birds, with 30 of its 50 recorded species known to nest there.

A potential threat to the area is erosion of the dike on the lower end of the east site. Burning would control weed growth along the creek and remove exotic species from the remnant upland prairie.

8. North Little Salt Creek

The lowland along Little Salt Creek north of Lincoln is still mostly native vegetation; it is used only for grazing because it is so wet and saline. The two sites listed here represent the most notable areas identified and visited; other saline areas can be expected elsewhere along the creek, where appropriate soils exist.

8a. First Street and Raymond Road

S 1/2 of the NW l/4 of Section 2, T11N, R6E.

Soils: Sa, Sb

This area is heavily grazed by the lessee, but there is excellent potential for rejuvenation of the wetland and native prairie on the nearby upland through reduction in grazing intensity. The habitat diversity is very good.

The lowland area includes lowland cordgrass meadow, small saline flats, limited cattail marshes, and two channels of Little Salt Creek. Saline plants noted on the bottomland include spearscale and saltwort.

On the upland in the southwest corner of this tract is a native prairie with big bluestem, little bluestem, blue grama, switchgrass, sideoats grama, and gayfeather. A small area where there was once a quarry has two ponds, and the excavation work has exposed Dakota sandstone. There is an oxbow lake to the west, along the creek.

8b. Little Salt Fork

T12N, R6E, middle 1/3 of W 1/2 of Section 34.

Soils: Sa, Sb

This area has several marsh habitats along two forks of Little Salt Creek, and is biologically rich. There are mud flats, emergent wetland, lowland meadow, and upland bluestem prairie. There are rolling hills of native prairie with wetlands between them. The increase in elevation creates a transition from barren ground and meadow along the creek to wetlands and upland prairie. Grazing has reduced the biotic diversity.

Acknowledgements

The habitat assessments for the North 27th Street, North 40th Street, and Lagoon Park areas were prepared with the assistance of David Sutherland of the University of Nebraska at Omaha. Robert Kaul of the University of Nebraska-Lincoln also helped by providing floristic information based upon his knowledge of saline wetlands. Bird records were contributed by William Garthright of Lincoln (for Capitol Beach and Federation Marsh), Paul Johnsgard of the University of Nebraska-Lincoln (for Lagoon Park and North 27th Street), and Don Showen of Lincoln (for Lagoon Park).

References

American Ornithologists' Union. 1983. Checklist of North American Birds, sixth ed.: 877 p.

Barbour, E.H. 1985. Lincoln Salt Lake and the occurrence of Strepsilas interpes. Auk, 12: 297.

Cunningham, D. 1985. Villains, miscreants and the salt of the earth. Nebraskaland, 63: 14-19, 45-47.

Ducey, J. 1985. Nebraska's salt basin: going, going, nearly gone. Nebraskaland, 63: 20-25.

Ducey, J. 1987. Frank H. Shoemaker: turn-of-the-century naturalist, Missouri Valley and Salt Lake. Nebraskaland, 65: 12-17, 45-46.

Eiche, A. 1901. Breeding of the snowy heron and swallow-tailed kite. Proceedings of the Nebraska Ornithologists' Union, 2: 96.

Elmore, C.J. 1921. The diatoms (Bacillarioideae) of Nebraska. University of Nebraska, University Studies, 21:22-215.

Kaul, R.B. 1975. Vegetation of Nebraska. Map, 1:1,000,000. Conservation and Survey Division, University of Nebraska.

Lunt, S.R., and W.F. Rapp, Jr. 1981. An annotated list of the mesquites of Nebraska. Mosquito News, 41: 701-706.

Hunter, J.S. 1900. The bird fauna of the salt basin, near Lincoln. Proceedings of the Nebraska Ornithologists' Union, 1: 18-21.

Pickwell, G. 1925. Some nesting habits of the belted piping plover. Auk, 42: 326-332.

Shirk, C.J. 1924. An ecological study of the vegetation of an inland saline area. Ph.D. dissertation, University of Nebraska-Lincoln: 126p.

Soil Conservation Service, 1980. Soil survey of Lancaster County, Nebraska. U.S. Department of Agriculture: 174 p.

Ungar, I.A., W. Hogan, and M. McClelland. 1969. Plant communities of saline soils at Lincoln, Nebraska. American Midland Naturalist, 82: 564-577.