Rainfall to blame for decline in Arctic peregrines

Rain, crucial to sustaining life on Earth, is proving deadly for young peregrine falcons in Canada's Arctic.

A University of Alberta study recently published in Oecologia shows that an increase in the frequency of heavy rain brought on by warmer summer temperatures is posing a threat not seenin this species since before pesticides such as DDT were banned from use in Canada in 1970.

The study is among the first to directly link rainfall to survival of wild birds in Canada.

A nest-box experiment at the heart of the study, co-written by U of A researcher Alastair Franke and Alexandre Anctil of the Universit? du Qu?bec, has provided "unequivocal evidence" that gradual changes in Arctic temperature and precipitation are responsible for a long-term decline in reproduction for the peregrine, a top predator in the Arctic.

The change in rainfall patterns in recent years has had a big influence on the overall decline in reproductive success over the last three decades, Franke said.

Paired with historical weather data and measures of breeding success dating back to 1980, the researchers also conducted a nest-box experiment from 2008 to 2010 in a dense population of peregrines breeding near Rankin Inlet in Nunavut on the shores of the Hudson Bay. Falcon nests were monitored using motion-sensitive cameras, and images confirmed that more than one-third of the chick deaths recorded were indeed caused by rain, whether they were raised in nest boxes or on natural ledges.

"The nestlings died from hypothermia and in some cases from drowning in their flooded nests. Without constant parental care, they are most vulnerable to cold and wet conditions in the first three weeks of life."

Over the past 30 years, scientists have been surprised to discover an ongoing decline, even when pesticide residues were known to be too low to cause reproductive failure.

"We knew DDT was no longer an issue and based on field observations, we wondered whether changes in climate were responsible for high mortality in recent years," Franke said.

Besides deaths attributed to rainfall, the study also revealed additional fallout for chicks: starvation.

"We were surprised to find that a considerable number of nestlings raised in nest boxes later died of starvation despite having been spared from the direct effects of rain."

Believing that storms may also be the culprit in reducing the abundance of prey for peregrines, Franke has launched a food supplementation study to explore the possible link.

Grim as the study's findings are, "they have improved our understanding of the direct effects of long-term changes in weather patterns and have identified the potential importance of indirect effects," Franke said.

The work also shows that wildlife can be sensitive to many different environmental pressures and that ongoing vigilance and monitoring is critical, he noted.

The study was funded by ArcticNet, the U of A's Canadian Circumpolar Institute, the Nunavut Wildlife Management Board and Department of Environment, the Natural Sciences and Engineering Research Council of Canada, the Fonds de recherche Nature et technologies Qu?bec and a W. Garfield Weston Award.

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In South Dakota, some blame Corps for flood threat (AP)

FORT PIERRE, S.D. – Sitting atop a 6-foot wall of white sandbags hastily stacked to protect his home from the rising Missouri River, 82-year-old Helmet Reuer doesn't buy the official explanation that heavy rains caused a sudden flood threat.

Along with his neighbors in an upscale section of Fort Pierre, Reuer thinks the U.S. Army Corps of Engineers blew it, waiting until too late to begin releasing water through the Missouri's six dams to give itself a cushion against potential flooding.

"It's human error," Reuer said as rising water neared his trim gray house.

Corps officials insist otherwise. They say they were in good shape to handle spring rain and melt from a massive Rocky Mountain snowpack until unexpectedly heavy rains of 8 inches or more fell last month in eastern Montana and Wyoming and western North Dakota and South Dakota.

"This is just a massive rain that fell in the exact wrong place at the exact wrong time," said Eric Stasch, operations manager at Oahe Dam, the huge structure that controls the Missouri's flow just above Fort Pierre and nearby Pierre, South Dakota's capital.

Crews have worked urgently all week to build up levee protections for the two cities, and say they expect to have 2 feet to spare. But Gov. Dennis Daugaard advised people in neighborhoods nearest the river to leave voluntarily in case levees don't hold, and hundreds have done so after a hectic week of moving possessions and adding sandbags around their houses.

They face weeks out of their homes until the river begins cresting in mid-June, with high water expected to linger for up to two months. The small town of Dakota Dunes, S.D., in the southeastern tip of the state, has also erected levees, as has Bismarck, N.D., though the situation is less serious there.

"I think they screwed up royally," former Gov. Mike Rounds said of the Corps, as he moved some possessions from the riverbank house he and his wife built and moved into after he left office in January. "I think they forgot their No. 1 mission, and that's flood protection."

People here were prepared for some higher flows, but many were startled when the Corps announced May 26 it needed to release water much faster than expected from the dams in Montana and the Dakotas.

Jody Farhat, chief of Missouri River Basin water management in the corps' Omaha District, said the agency made no mistakes and has managed releases in accordance with its manual. She said conditions on May 1 indicated peak releases at only a third of what they're now projected, and the reservoir system had full capacity to deal with flood control at the start of the runoff season. All that changed with the record rainfall in the upper basin and additional snow in the mountains, she said.

Farhat said heavy runoff from last year was released before the start of this year's runoff season, and discharges this spring were above normal even before the heavy rainfall upstream.

Corps officials declined a request for a one-one-one interview and provided some information by email, but in a teleconference Thursday, Farhat said the reservoirs had reached the desired levels before snowmelt was to begin.

"And what happened was we had this incredible rainfall event," Farhat said. "That was a rainfall event in May, and that was the game-changer in terms of system operations."

People who live in the flood-threatened areas say this wasn't supposed to happen.

The Missouri River dams were built to control periodic spring flooding and provide hydropower, irrigation and other benefits after Congress passed the Flood Control Act of 1944. Fort Peck Dam, in northeastern Montana, was already operating in 1940 and Oahe, a massive reservoir that runs from North Dakota to the dam near Pierre in central South Dakota, was completed in 1962. Big Bend, about 60 miles downstream from Oahe, was the last dam finished, in 1964.

This is not the first fight over Missouri River water management, but the dispute has more often been about too little water. A series of lawsuits was filed during a prolonged drought that started about a decade ago. Upstream states wanted more water left in the reservoirs to support a growing sport fishing industry, while states downstream wanted more water to support barge traffic on the free-flowing stretch from Sioux City, Iowa, to St. Louis.

The U.S. Supreme Court declined to consider the legal fight in 2006, leaving intact a federal appeals court ruling that said navigation trumps upstream recreation and other interests when the Corps of Engineers manages the river.

In Montana, officials in downstream communities said some people faulted the Corps for not releasing water earlier from Fort Peck Dam, the first in the series of water-control structures on the river.

But Roosevelt County Commissioner Gary MacDonald said he was reluctant to blame the federal agency.

"That's the sentiment here of why did they wait," MacDonald said. "There's no better person for the average John Doe to blame out there than the Corps. They're taking the brunt of it because they're controlling the flow."

Back in South Dakota, Daugaard also declined to criticize the Corps, saying he had seen "no evidence that they're working other than in good faith" to deal with the situation.

At Oahe Dam, the quickening pace of the water releases through rarely used gates — more than 100,000 cubic feet per second and building — makes for a foaming, thundering spray that brought spectators by the carload before it was closed for safety reasons. But many here have no time to appreciate the river's power.

"I'm tired and I'm sick," Mike Richardson said as he loaded household items into a trailer to move them from his Fort Pierre house to higher ground. "I'm better off than a lot of people, I know, but I still can't help but feel sorry for myself. ... Somebody really dropped the ball on this deal."

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