The Audubon Society of Omaha is pleased that the U.S. Fish and Wildlife Service has provided this opportunity to present additional comments on classification of the belted Piping Plover as a threatened species.
After reading the federal register, it was evident that important information needed to evaluate the status of the Plover was not considered in this public notice. Relevant documents include notes on the historic breeding distribution of birds in Nebraska, changes in breeding habitat and specifics on identification of the subspecies resident on the northern Great Plains.
First of all we would like to provide a perspective on the recorded breeding distribution of this species in Nebraska. Observations of Piping Plovers during the past 180 years show that nesting has occurred on the four major river systems, a saline lake in southeast Nebraska and in association with groundwater wetlands in the Sandhills.
The first known observation on the Missouri River was during the Lewis and Clark Expedition in 1804-05. The Piping Plover was identified as being a species that frequent drift (or sandbars) on the river as far north as the mouth of the Little Sioux (Swenk 1935). Several additional records document breeding in 1866 in Dakota County (Moser 1942), while during the 1940's nesting was also recorded near Omaha at two cutoff lakes, Lake Manawa (Stiles 1940) and Carter Lake (Moser 1940, Moser and Haecker 1941). During the early sixties birds occurred at DeSoto NWR (CNRC R.G. Cortelyou, 1966). Recent Nebraska Game and Parks Commission surveys show nesting occurrence only along sandbars of the Missouri National Recreation River in northeast Nebraska, with only two additional breeding sites along the southern portion of the river in Iowa. One site is at the settling ponds of the power plant south of Council Bluffs (Wilson and Padelford 1983) and at similar ponds at a power plant near Sioux City (Iowa Conservation Commission, unpublished records, B. Wilson, pers. comm).
There are few documented records for nesting but those available do indicate the range that Piping Plover once had along the Missouri. The observations by Lewis and Clark indicate a species occurrence in suitable habitat present along the Missouri River adjacent to the present day boundary of Nebraska. The habitat available was first quantified by land surveys during the 1890's by Corps of Engineer personnel who prepared detailed maps of landscape features (Missouri River Commission 1892-95). The illustrations show the common occurrence and large extent of sandbars. Some of which were up to several miles in length. Cutoff lakes also were shown to have sand beaches. The large amount of sand substrate available for nesting prior to the 1940's would have provided excellent habitat for use by Piping Plover.
Decades ago, breeding activity was noted along the river in Cass (Heinemann 1944), Platte (Shoemaker 1941), Dawson (Wycoff 1960), and Lincoln (Audubon Field Notes 3:244, 1949). Counties that indicate this species was breeder along this portion of the river. More recent observations add Hall (CNRC L.A. Peterson, 1958; Lingle and Hay 1982) and Keith (CNRC S. Stephens and R. Brooks, 1967) Counties to the known area of distribution. Records that have been collected in association with Least Tern surveys during the past few years provide a perspective on the current known distribution. Nesting has been documented by personal field efforts, Game Commission surveys, as well as in association with activities at the Morman Island Crane Meadows. Plover distribution along the Platte River in the eighties occurs along the eastern two-thirds of the river with birds also breeding on the shoreline of Lake McConaughy (American Birds 32:1180; Rosche and Johnsgard 1984). More typical nesting sites used include mid-channel sandbars as well as sandpits adjacent to the river.
On the Loup River system, the first record for nesting was on the South Loup near Dannebrog, Howard County at the turn of the century (Anderson 1900). There were no additional records until recently when nesting was found on river sandbars along the river and dredged sand piles at the mouth of the Loup irrigation canal in Nance County (Molhoff 1983). Nesting was probably continuous during the period between these dates.
Nesting birds common along the Niobrara east of Springfield in 1902 (Ducey 1983) as well as observations made in the past few years confirm nesting of the plover during the historic period as well as currently. The Niobrara has suitable habitat only along the approximately lower 100 miles with the sandbars that are present today providing important undisturbed breeding sites. Nesting birds are recorded each year by Game Commission personnel. This river has been relatively unchanged as a haven for breeding waterbirds like the Plover.
The Piping Plover has also been found to occur away from rivers. At the turn of the century nesting was noted at Trout Lake in the sandhills of Cherry County (Moser 1942). Around 1920 nesting was once again recorded in this region with a set of eggs being collected in Garden County (Maryott 1922). During the 1920's nesting activity was observed at Capital Beach near Lincoln (Pickwell 1925). The nests were placed on sand left by dredging operations. There has been no recent efforts made to determine if Piping Plover still occur in association with the alkali flats or sand beaches of lakes in the Sandhills. The Capital Beach area is now predominantly a residential development.
Recent field research investigating the occurrence of Least Terns has meant additional information to assess the distribution range and data on populations of the Plover. The more numerous records of nesting for the past few years are a direct result of increased field activity with nesting being confirmed for counties within the breeding range. As for populations, the Game and Parks has information collected in 1983 that showed a population of over 130 pair on the 50 miles of the Missouri National Recreation River. At two sites upriver from Lewis and Clark Lake an additional 4 pair were noted. On the lower Platte River, numbers exceeded 25 pair in 1981 but fewer were recorded in 1982. Additional numbers from scattered Tern colony locations provide further basis for population estimates. The total population for Nebraska, when using a combined count, exceeds the range of 100-300 given in the federal notice. A comprehensive census would show a small total population of birds that can be easily threatened.
The nesting records available for the Piping Plover in Nebraska provide a historic perspective on the extent of breeding habitat that can be compared to the current known occurrence. Within the overall distribution range of the Plover, the sites suitable for breeding, both past and present, were even further limited by strict requirements needed for nesting. Only when a suitable combination of open sand, water, and no more than scattered vegetation conditions occur, do birds dig their scrapes and rear young successfully. If the proper habitat for breeding is lost, for example due to a complete loss of sandbars or as a result of vegetative encroachment, birds would be forced to move to a different site.
Without suitable habitat, breeding birds would no longer occur in areas where they were once present. It has been changes in habitat that have had the most severe effect on the distribution of Piping Plover in Nebraska.
This impact has been most pronounced on the Missouri River. As a result of the Missouri River Bank Stabilization and Navigation Act construction during the last half century, over 25,000 acres of sandbar and sandbeach habitat are known to have been destroyed. This includes 20,000 acres or 99% of what was once noted between Nebraska City and Sioux City (Hallberg et al. 1979). Oxbow lakes no longer have suitable habitat either. Many of these old channels have dried up or been cultivated. Lake Manawa and Carter Lake are two examples of what has happened to habitat around Omaha. Open areas are now covered with vegetation, housing, or other urban development. From the mouth of the Little Sioux River to Gavins Point Dam, 7,804 acres of sand were changed to other land use between 1956 and 1975 (Siouxland Interstate Metropolitan Planning Council 1978). This includes a decrease in the amount of overall sand habitat along the Missouri National Recreation River. Additional unrecorded acreage was lost for the portion of the river south of Nebraska City to the southern boundary of the state.
Sandbars along the entire eastern boundary of Nebraska have been virtually eliminated with the exception of those along the Missouri National Recreation River. What remained along the fifty mile stretch in 1980 was only 2,198 acres of terrestrial sandbar (Schmulbach et al. 1981) of which even a smaller amount would be appropriate for nesting. So from an approximate figure of at least 30,000 acres in the past less than 10% remains somewhat similar despite less than 100 years of landuse and development.
On the Platte, changes in channel characteristics have meant a loss of open sandbar habitat. The decrease in overall width of the river and vegetative encroachment on sandbars are problems caused by narrowing of the active channel and changes in the flow regime of the river.
There have been no recognized impacts on breeding habitat along the Niobrara and Loup River systems that have had a negative effect on breeding habitat. The Niobrara especially has excellent quality, relatively undisturbed sandbars supporting a good number of birds.
BENEFITS OF CLASSIFICATION
Habitat loss is the most severe long term influence on breeding bird populations. In order to conserve a species, breeding habitat must be maintained. Identification of sites that are recognized as having the habitat needed by Plovers can help maintain conditions suitable for breeding. We would suggest that the Fish and Wildlife Service designate as critical habitat, specific known nesting areas with a history of use by Piping Plover. Two examples are federal wildlife refuges and river stretches with sandbar habitat.
Planning considerations available through Endangered Species Act classification would insure that federal projects which may influence Plover would be evaluated prior to any activity. Several past projects have had profound negative impacts with planning underway on additional projects that could influence Plover habitat. These include the proposal for the increase in the pool level of Lewis and Clark Lake, the O'Neill Unit irrigation project on the Niobrara, and numerous plans for water diversion and dam structures on the Platte.
CURRENT BENEFICIAL MANAGEMENT
Despite the overall trend for declines in the extent of habitat available to this species, several current management efforts help protect and maintain habitat. At DeSoto NWR, there is plant control underway to maintain a large open sand area that was cleared of vegetation attract nesting Least Terns can be used by Piping Plover. The settling pond nesting area at the Iowa Power and Light power plant south of Council Bluffs has a protective easement. On the Platte, sandbar clearing efforts by the Platte River Whooping Crane Habitat Maintenance Trust have provided habitat for nesting Terns as well as Plover.
On the Missouri River, the Corps of Engineers is considering how general plans for reservoir operation can be established to modify flow releases from Gavins Point Dam and reduce the potential for inundation of downriver breeding activity. The prevention of flooding of nesting sites would be extremely beneficial for this portion of the river. Along the fifty miles below the dam, the cooccurrence of Piping Plover and Least Tern is unique in the Great Plains. There is no other site in this region with such a high combined density of both species.
PIPING PLOVER IN NEBRASKA
The Piping Plover in Nebraska should be considered a unique part of our wildlife heritage with a special history of its own. The status of this species through the years confirms a decline in breeding range, with other known or potential negative influences A indicate the need for active conservation and management. Not only is there the inherent need to retain a viable population of Plover in Nebraska, but it is important to realize the natural resource value and aesthetic appreciation provided by Piping Plover and other native wildlife running along the sandbars and beaches of Nebraska and elsewhere. But also, here in our state there are two additional scientific facts about Piping Plover that need special recognition.
One is that specimens of the Piping Plover collected in the mid 1850's at the confluence of the Platte and Loup Rivers provided the skins used to describe the belted subspecies found on the Great Plains. The government sponsored Warren expedition collected a few birds with a distinctive black pectoral band completely across the upper chest that did not occur on birds of the east coast or Great Lakes region. The interior race was designated the Belted Piping Plover with ecological differences in the birds breeding environment contributing to the plumage differences. Almost 100 years later, at Carter Lake, just north of town, an Omaha birder made further observations that detailed the variation in markings between the three recognized subspecies of the Piping Plover (Moser 1942). The reference detailing these characteristics was not even mentioned in the federal notice.
Just recently, in 1983, field work on nesting activity along the Missouri National Recreation River, there were two records of eggs of the Least Tern being found in nests of the Piping Plover. Such an occurrence has never been previously recorded in the ornithological literature.
To conclude, the Audubon Society of Omaha strongly supports classification of the Piping Plover as a threatened species. The information available shows there has been a marked decline in suitable habitat that has had a direct effect on breeding distribution and success. Proper recognition of this part of our natural heritage, suitable management and active conservation measures are needed. Federal classification would implement action to help achieve these goals.
Literature cited and pertinent references
Anderson, G.P. 1900. The belted piping plover. Oologist 17: 156.
Bennett, E. 1983. Nineteen eighty-two Nebraska nesting survey. Nebraska Bird Review 51: 26-32.
Bennett, E.V. 1984. Nineteen eighty-three Nebraska nesting survey. Nebraska Bird Review 52: 47-50.
Ducey, J. 1981. Breeding of the least tern and piping plover on the lower Platte River, Nebraska. Nebraska Bird Review 49: 45-51.
Ducey, J. 1982. The 1982 least tern and piping plover breeding season on the lower Platte River, Nebraska. Nebraska Bird Review 50: 68-72.
Ducey, J. 1983. Notes on the birds of the lower Niobrara River in 1902 as recorded by Myron H. Swenk. Nebraska Bird Review 51: 37-44.
Hallberg, G.R., J.M. Harbaugh, and P.M. Witinok. 1979. Changes in the channel area of the Missouri River in Iowa. Iowa Geological Survey, Special Report Series Number 1. 32 pp.
Heinemann, L. 1944. Nesting of the piping plover and least tern in Cass County, Nebraska. Nebraska Bird Review 12: 9-10.
Lingle, G. and M. Hay. 1982. A checklist of the birds of Morman Island Crane Meadows. Nebraska Bird Review 50: 27-36.
Maryott, M. 1922. Unpublished collection records.
Missouri River Commission. 1892-95. Maps of the Missouri River from its mouth to Three Forks, Montana. Missouri River Commission. Index and 83 pp.
Molhoff, W. 1983. Piping plover and least terns. Nebraska Bird Review 51: 94.
Moser, R.A. 1940. The piping plover and least tern nesting in Omaha. Nebraska Bird Review 8: 92-94.
Moser, R.A. 1942. Should the belted piping plover be recognized as a valid race? Nebraska Bird Review 10: 31-37.
Moser, R.A. and F.W. Haecker. 1941. The belted piping plover returns to its nesting site in Omaha. Nebraska Bird Review 9: 14-15.
Pickwell, G. 1925. Some nesting habits of the belted piping plover. Auk 42: 326-332.
Rosche, R.C. and P.A. Johnsgard. 1984. Birds of the Lake McConaughy and the North Platte River valley, Oshkosh to Keystone. Nebraska Bird Review 52: 26-35.
Schmulbach, J.C., J.J. Schuckman, and E.A. Nelson. 1981. Aquatic habitat inventory of the Missouri River from Gavins Point Dam to Ponca State Park, NE. Corps of Engineers Job Completion Report Contract #DACW45-80-C-0155. 15 pp.
Shoemaker, F.H. 1941. Unpublished field records.
Siouxland Interstate Metropolitan Planning Council. 1978. Missouri River woodlands and wetlands study. 105 pp.
Stiles, B.F. 1940. Nesting of the piping plover in Iowa. Iowa Bird Life 10:48-49.
Swenk, M.H. 1935. A history of Nebraska ornithology. III. Period of the explorations of the early century (1804-1854). Nebraska Bird Review 3: 115-120.
Wilson, B.L. and L. and B. Padelford. 1983. Piping plovers nests in Pottawattamie County. Iowa Bird Life 53: 69-70.
Wycoff, R.S. 1960. The least tern. Nebraska Bird Review 38:39-42.
- CNRC stand for Cornell Nest Record Card.
- @ - circa, which indicates a general time period when a specific date is not presented.