03 February 2010

Status of Snowy Plover Revealed by Threatened and Endangered Species Research

The status of the Snowy Plover - a species only recently discovered as nesting in Nebraska and the northern Plains - is better known due to research on two endangered bird species.

Ongoing studies of the endangered interior Least Terns and threatened Piping Plovers on the Missouri River and the Big Bend region of the central Platte River have only recently also documented nesting by the Snowy Plover.

A Snowy Plover nest was first noted in Nebraska on June 10th, 1998 on a sandbar at the west end of Lewis and Clark Lake, along the Missouri River, near Santee, Nebraska. It was denoted by Greg Pavelka, a Corps of Engineers project manager. This was a significant event, adding this plover to the list of breeding species, and the official date for the state's historic ornithology.

Years later, in 2008, researchers from Virginia Polytechnic Institute and State University (VPI) documented two snowy plover nests on the constructed sandbar complex at river mile 826.5 on Lewis and Clark Lake, according to Pavelka, program manager for the least tern and piping plover monitoring conducted by the Army Corps of Engineers.

Scientists from VPI have been studying the population dynamics of the Piping Plover on the Missouri National Recreation River since 2005.

During the 2009 season, the VPI researchers under the direction of Dr. James Fraser documented ten Snowy Plover nests, Pavelka said. "Eight of these nests were successful with at least one egg hatching, one nest was lost to weather and one nest was lost predation." The VPI researchers tracked 14 snowy plover chicks.

"It was certainly very exciting to see these guys breed on Lewis and Clark Lake," said Dr. Daniel Catlin, a Research Scientist with the Department of Fisheries and Wildlife Sciences at VTI, and whom just recently received his doctorate for studies on the population dynamics of the Piping Plover. "In years prior they had been periodic visitors, and I was waiting for the first eggs to drop on sand."

Constructed sandbar complex at the west end of Lewis and Clark Reservoir, Knox County Nebraska. Image courtesy of Greg Pavelka.

The "nest substrate for the snowies is similar to the piping plovers, but they do not line their nests on the Lewis and Clark sandbars," Catlin said. "They actually look like a mixture of a least tern nest and a piping plover nest. The eggs are a slightly different coloration than the plovers, and they only lay three whereas the pipers initially lay four. It is hard the first time that you see one to determine that it is, but they look just different enough that it raises questions."

Last summer at this constructed sandbar complex, the Least Tern had 93 successful nests, and the Piping Plover 56 successful nests, according to the Corps findings.

Construction on the sandbar complex was begun in 2006 and was completed in 2008. The complex was built as a part of the Corps' emergent sandbar habitat program to provide breeding habitat for least terns and piping plovers on the Missouri River. There is about 305 acres of sandbar habitat available at this complex that is suitable for nesting by the tern and plovers.

Central Platte

The Snowy Plover has been breeding along the central Platte River only since 2007.

"A pair of snowy plovers and a nest, however, was observed at the Dinan Tract site during weekly site surveys in 2008 and 2009; snowy plover chicks fledged at the Dinan Tract site during 2009," according to the report "Interior Least Tern and Piping Plover Monitoring and Research Report for the Central Platte River, Nebraska" just released by the Platte River Recovery Implementation Program office in Kearney. "Two snowy plover nests were also observed at the Dinan Tract site in 2007; one fledged young," according to David Baasch, the author of the report.

There has now been three breeding seasons with snowy plovers at this site, so "there seems to be a biased selection for this area," said Matthew Rabbe, a Fish and Wildlife Service biologist that has studied these birds. "The Dinan tract islands may stand out differently from other areas in that it has the largest number of islands managed in a relatively small section of the central Platte River."

Least Terns and Piping Plover also nest at this 200-acre tract, located on the Lillian Annette Rowe Audubon Sanctuary, on the Platte River south of Gibbon, and which was dedicated in 2007.

The area is a restoration project created and managed by the Partners for Fish and Wildlife Program.

North Dakota

"In 2007, snowy plovers were observed on both the sparsely vegetated shorelines of alkaline lakes and sandbars on the Missouri River system during regular surveys for piping plovers and least terns," according to a report prepared by Pavelka and biologists with the Fish and Wildlife Service. "Three 1-5 day old chicks were seen on the sandbar on the Missouri on July 13, but were not seen on the next three weekly visits. The crew concluded the chicks did not fledge."

Also in Dakota, there was one nesting documented at on the Missouri River below Garrison Dam and one on Lake Oahe, where "two chicks hatched from the nest and these two were documented as having fledged," Pavelka said. "The appearance of snowy plovers in the Dakotas corresponds with spring flooded conditions in Texas, Kansas, and Colorado, which precluded nesting in traditional areas. These birds may be displaced migrants that continued north to find appropriate nesting habitat," he said.

In 2007 and 2008, Snowy Plovers also nested in North Dakota at Long Lake NWR, said Catlin. They were not present in 2009.

There were no snowy plovers documented by the Corps in North Dakota in 2008 and 2009, according to Pavelka.

Irrigation Reservoirs Habitat

Nesting at this reservoir on the western Platte was first noted in 2000, when a small chick with a female was noted, according to records gathered by Nebraska bird watchers. In 2001, an adult female with three young was noted on the south beach in mid-August. Additional nesting occurred in subsequent years.

In 2004, nesting occurred also at Harlan County Reservoir, according to an account of the status of the Snowy Plover, as maintained by Ross Silcock. There have been no subsequent records for this locality.

The Snowy Plover is classified as having a "peripheral" breeding range in Nebraska, Silcock said, as its range on the Great Plains is generally from Kansas southward.

The extent of nesting in 2009 may indicate this species is making Nebraska an inclusive part of its regular breeding season range.

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