Nesting interior least terns and piping plovers are not having a good summer at Lake McConaughy.

Coyotes, roaming dogs and other predators are raiding nests, eating eggs and chicks, and sometimes adult birds, at the state's largest reservoir near Ogallala in western Nebraska.

And hordes of campers - thousands of them on holiday weekends - are encroaching on historic nesting grounds with RVs and all-terrain vehicles.

After years of drought, rising water levels are reducing beaches, so the birds, which nest in cuplike depressions in the sand, are pinched between the water and shoreline vegetation.

"It's been going on for several years and now it's become very bad," said Mary Bomberger Brown, program coordinator for the Tern and Plover Conservation Partnership founded in 1999 and based at the University of Nebraska-Lincoln.

Interior least terns are on the U.S. Fish and Wildlife Service's endangered species list.

Piping plovers are on the threatened species list, which means they're likely to become endangered in the foreseeable future.

Bomberger Brown said the group's main focus has been protecting tern and plover habitat along the lower Platte River downstream from Columbus, but it's become increasingly concerned about what's happening at Lake McConaughy.

"Memorial Day to Fourth of July was very hard on them," Bomberger Brown said. She believes very few, if any, young birds survived.

Lake McConaughy's white sand beaches are a magnet for campers, who park their RVs and camper trailers on the beach. They also drive golf carts and all-terrain vehicles on the beach, where least terns and plovers like to nest.

The people and vehicles create a hazard for young birds trying to get to the water to forage.

"Mix beer and people and put them behind the wheel, the birds do very badly," Bomberger Brown said.

Mark Peyton, senior biologist with the Central Nebraska Public Power and Irrigation District, which operates Lake McConaughy and Kingsley Dam for irrigation and hydroelectricity, agreed that nesting birds are not doing well.

But Peyton said predators - not people - are the biggest problem. Coyotes and dogs are the primary predators, but officials also are seeing evidence of damage from gulls, grackles and snakes.

As part of its federal license to operate Kingsley Dam, the Holdrege-based district is required to protect tern and plover habitat but also provide for recreation.

For the past nine years, Lake McConaughy has been one of the most important nesting areas in the Great Plains for piping plovers, according to Peyton. The lake is home to about 135 pair of plovers and 11 pair of least terns.

Fifteen years ago, the district started to monitor least tern and piping plover nests. It also put up enclosures to protect nesting grounds. Central takes the protection measures in consultation with the U.S. Fish and Wildlife Service and the Nebraska Game and Parks Commission, which leases the shoreline of the 20-mile-long lake at no cost.

"Last year we had a bunch of nests destroyed and we didn't know why," Peyton said.

After that, Central officials met with U.S. Fish and Wildlife and Game and Parks officials and started an aggressive monitoring program, visiting each nest once a day, seven days a week. By doing so, Peyton said, the visits may have put additional stress on the nesting birds.

"I think for the most part that people at the lake have respected our enclosures and don't deliberately try and kill the birds or destroy the nests," Peyton said.

But, he said, the monitoring and enclosure program may have actually led to an increase in predation.

"We probably trained predators to look for our enclosures," said Peyton, explaining that coyotes and dogs may be following the trail of workers to the enclosures, which are marked by posts and orange twine to alert drivers.

In other parts of the U.S. where the birds are protected, officials close a quarter mile of beach for every least tern and plover nest, Peyton said.

"If we had to do that at Lake McConaughy, we would have to close the beach completely," he said. "We do it in minimal fashion to allow for recreation and to protect the birds."

Lake McConaughy is almost 11 feet higher than last year at this time, and Peyton said the birds did better during drought years.

Then, he said, the lake level was very low and people were more spread out. Now the crowds have moved closer to historic nesting areas because the beaches are shrinking.

Martha Tacha, a biologist with the U.S. Fish and Wildlife Service office in Grand Island, said the situation at Lake McConaughy is serious.

"Whenever you have endangered or threatened species, losses are regrettable, whether it's predation or human disturbance or whatever," she said.

Tacha said Peyton and his staff are doing a good job by putting up the barriers to separate the birds from the people who visit the lake.

But Bomberger Brown would like to see federal laws that protect endangered and threatened species enforced and people held accountable if they destroy nests and kill birds. Criminal penalties include as much as a year in prison and a $100,000 fine.

Peyton plans to discuss Central's monitoring and enclosure plan for next year with Fish and Wildlife and Game and Parks officials to see if Central could do things differently to protect nesting areas.

Possibilities include adding one or two large protected areas, and reducing the frequency of checking on nests by employees.

"We won't make people happy, but we won't have to close the entire beach," Peyton said. "And we probably won't visit (each nest) every day."

Reach Algis J. Laukaitis at 473-7243 or alaukaitis@journalstar.com.