More than 34,600 American white pelicans - a near record - are nesting at Chase Lake National Wildlife Refuge, a breeding ground that has seen more pelican pullouts than successes in recent years. The population estimate is based on photos taken by the U.S. Fish and Wildlife Service during a May 31 flight over the nesting islands north of Medina.

The photos showed 17,302 pelican nests. Biologists estimate two adult pelicans per nest, putting Chase Lake's breeding age pelican population at 34,604 birds.

The refuge's pelican population last year was 9,425 nests, or 18,850 birds.

The big bounce in pelican numbers is because of the successful nesting seasons in the early 2000s, and chicks hatched in one or more of those years now have reached breeding age, said Tomi Buskness, Chase Lake project manager. Pelicans reach breeding age between 3 and 5 years, she said.

The refuge had a record high number of breeding adults in 2000 - 35,466, or 17,733 nests.

"We had high years after that, 2001 and 2002," Buskness said.

Pelican setbacks began in late May and early June 2004 when about 30,000 adults abandoned the refuge, leaving behind eggs and chicks. Biologists speculated that a coyote intrusion may have been the cause.

An estimated 18,850 adult pelicans pulled out last year after almost all of their chicks died following two bouts of cool, wet and windy weather that hit the chicks after the adults had stopped brooding them.

"They were on their own and pretty much defenseless," said Ken Torkelson, a USFWS spokesman in Bismarck.

The West Nile virus also appears to be a factor in chick deaths. Since 2002, biologists have blamed the virus for the deaths of thousands of young birds after mid-July at Chase Lake and other large colonies in adjacent states.

Everything appears normal this year, Buskness said.

"So far, everything is looking great. We're keeping our fingers crossed that we don't have the weather events,"Buskness said. "West Nile may also be a factor, but we won't know for the next couple of months."

Before the 2004 abandonment, nesting pelicans occupied two islands and a peninsula. Now they nest solely on the islands.

"They are in the same locations as last year, just more of them," Buskness said.

Observers from the U.S. Fish and Wildlife Service and the U.S. Geological Survey's Northern Prairie Wildlife Research Center, with support from the N.D. Game and Fish Department, will continue to monitor the colony.

"We have individual monitors out three or four times a week. We have video cameras out there too. Observation is done remotely. If we go out there, it's done in a way that's not disturbing to the pelicans," Buskness said.

Pelicans began returning to the 4,385-acre refuge in early April this year and continued to arrive through late May.

"We're very encouraged by the number of pelicans that have returned to Chase Lake National Wildlife Refuge," Torkelson said. "However, we have a long way to go before we can say we've had a successful nesting season."