Magpies threatened by West Nile virus

In the world of the birds and the bees, we're in the throes of the mating season for many creatures out there.

Take a walk along the American River, for instance, and you'll find signs of that old, familiar hankering at every turn. There'll be mallards in pairs, splashing and flirting around puddles. You don't have to look far to find goose couples flying off to who-knows-where to do you-know-what.

More demonstrably, the wild turkey is acting out its equivalent of a singles bar pickup routine – large, colorful males puffing out their tail feathers to attract that coy female that can't help but look.

The yellow-billed magpie is at it, too. Only for this bird – monogamous, handsome, handy around the home and found only in Central California – reproducing may be a race against time.

Since 2004, when West Nile virus swept into California via infected mosquitoes, the large black and white bird with the iridescent blue wings and distinctive yellow bill has been the hardest hit of all. They've been in the news mostly because they have been dropping dead in droves.

Some observers are even talking about the possibility that the yellow-billed magpie could become extinct if the trend doesn't change.

"I'd say this is listing level. It means it's threatened or endangered," said Shawn Smallwood, a self-employed ecologist from Davis.

He renewed his study from the mid-1990s, done from a vehicle driven along a 126-mile route in the Central Valley, and found the number of magpies had declined 89 percent since West Nile.

"If this trend continues, we will not have yellow-billed magpies within three or four years," he said.

Bird-watchers from throughout North America know about the yellow-billed.

"A lot of birders have life lists where they want to see all the birds in North America, so they have to come here to see this one," said John Sterling, president of the 5,550-member Central Valley Bird Club.

The bird was once so plentiful and prolific in the area that almond farmers considered them a nuisance and offered bounties to have them killed.

West Nile virus is doing more than anyone with a shotgun ever could.

"The magpies in our area suffered significant losses," said David Brown, district manager of the Sacramento-Yolo Mosquito and Vector Control District. "Based on the research we've seen, magpies – when they are infected – won't recover. We haven't found any magpies yet that have developed an antibody response. That's the body's response to a viral infection. It certainly suggests the potential could be there (for extinction)."

Sterling is not convinced the yellow-billed will die off altogether.

Scott Crosbie, a 29-year-old doctoral student in ornithology at the University of California, Davis, went to a meeting about the magpie's plight in 2004, soon after the birds started dying.

"We didn't really have any answers. That's what fueled my current Ph.D. project," said Crosbie, who in early 2007 began counting magpies in designated areas four times a year.

"I was always interested in magpies, even as a kid. They're beautiful birds, and I just find them fascinating to watch," he said. "They're found nowhere else in the world, and they have not been well studied. "There is still a lot we need to learn about them."

Some things Crosbie admires about magpies: They hide, or cache, hundred of acorns and other seeds and can remember their locations; and with little more than sticks and mud, they are accomplished home builders known for their domed nests.

"They are incredibly agile and are very good at building these huge, elaborate nests," Crosbie said. "One researcher counted 1,500 sticks in a magpie nest."

It's too soon to know precisely how to respond to help the magpie. But scores of volunteers are pitching in to make observations and report dead magpies they find to Magpie Monitors, a program run by Holly Ernest, a wildlife veterinary professor at UC Davis and director of the Wildlife Genetics Laboratory.

"For reasons unknown to us, they are susceptible to West Nile virus," said Ernest, who said 82 percent of dead magpies reported to Magpie Monitors have been found to have the virus.

Ernest said she got the idea to monitor the magpies while riding her bike to work four years ago and wondering what would happen when West Nile virus landed in California after sweeping east to west across the country.

"It's a very striking bird with long, flowing feathers that remind me of a wedding dress in a way – very elegant," she said.

More than 300 citizen volunteers have reported magpie deaths to the program at www.magpiemonitor.org. The Web site describes several opportunities for volunteers and provides detailed information about the species.

Though Brown was not aware of magpies with antibodies, Ernest said one magpie so far has been found to produce West Nile antibodies, meaning the bird was able to survive the virus. It's the sole source of good news for the fate of the species.

"You can call it a glimmer of hope," the professor said.

According to Smallwood's study, which includes scores of birds besides the yellow-billed magpie, the scrub jay seems to be thriving despite taking an early hit from West Nile. His counts also suggest that the ubiquitous American crow had been holding strong until this year, when its numbers dipped significantly.

One less common bird victimized by the virus is the loggerhead shrike, which Smallwood describes as "a small songbird that thinks it's a hawk. It's the only songbird I'm aware of that kills other birds and mammals," he said.

The white-tailed kite, recognizable by its penchant for hovering, or "kiting," high above its prey in fields, also has declined since West Nile came to California.

The yellow-billed magpie is still visible in the area. A search early Saturday found them in and around trees adjacent to the American River bike trail and in at least two parks in midtown and downtown Sacramento.

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