Baltimore's birds attract other fans

THE BALTIMORE SUN

The Baltimore Ravens are just one win away from the Super Bowl, and Maryland's sports bars and office water coolers are suddenly awash in Ravens experts.

And come spring, those scholars of sport will molt their purple plumage, don orange, and become authorities on Russell Street's other birds, the Orioles.

But none can top Kevin E. Omland's credentials when it comes to Baltimore ornithological expertise. Omland, an evolutionary biologist hired in October by the University of Maryland, Baltimore County, studies ravens and orioles exclusively - the lower-case variety, that is. The sort with feathers.

Omland has discovered evidence that ravens in California are genetically distinct from those everywhere else. One of their distinctions is their fondness for Dumpster-diving.

And his genetic examination of oriole species throughout the New World has helped to buttress the Baltimore oriole's recently regained status as a distinct species. And he has traced the birds' ancestry to Mexico.

Omland has never seen the Ravens play, and he's only been to Oriole Park once. But his absence from Baltimore stadiums is not really his fault. He's from Vermont. "I grew up a Red Sox fan," he says.

He's not a big football fan, either. But he promises to do better. "I'll watch the playoffs," he says.

UMBC acquired Omland from the Smithsonian Institution's National Zoo for the 2000-2001 college season. Omland held a Smithsonian fellowship in molecular evolution.

"This department [at UMBC] has very strong researchers in molecular and cell biology," he says. "I can help them bring an evolutionary perspective to cell biology, and they can help me be more current in cell biology and apply it to evolution and behavior."

Coming to the land of upper-case Ravens and Orioles was just a coincidence. "It makes it easier for people to relate to the research we do," he says. And just maybe it will make it easier to find grant money to support his work.

Omland, 37, has admired ravens since his boyhood in Vermont, when he watched them fly high over the Green Mountains in their aerobatic courtship displays.

"They roll upside down, fall and pull out. I think they're great birds, wonderful birds to see," he says.

The species is found throughout most of the Northern Hemisphere, including the Appalachian summits, with no differences in appearance across their range.

Like their gridiron counterparts, the ravens' fortunes are improving. It could be their intelligence, or fewer potshots from people. But somehow their numbers have grown 1,000 percent in the past 30 years.

Omland and others wanted to know more. For example, whether there are genetic differences between Old World and New World ravens?

With bits of feathers, blood and tissue gathered from 72 far-flung ravens, (Omland will stoop to scoop roadkill for science) he and a team of colleagues from the U.S. Geological Survey and other institutions began to extract and sequence their DNA.

They used mitochondrial DNA, from the cell's energy factories, because it is believed to mutate or evolve much more rapidly than DNA in the cell's nucleus.

That makes it ideal for measuring the relatively brief times since closely related species began to evolve separately.

Omland and his colleagues reported in the Proceedings of the Royal Society of London, that - with one surprise exception - ravens from Maine to Murmansk, Russia, are a throroughly mixed genetic lot. They were not geographically distinct.

The exceptions were 28 ravens from California. They looked identical to the northern ravens, but their DNA was 4 percent different.

Mitochondrial DNA is believed to mutate at a steady rate of about 2 percent every million years. If so, the California ravens would seem to have split off from their northern cousins two million years ago.

Perhaps Ice Age glaciers eliminated ravens from much of the Northern Hemisphere, isolating one group in a refuge centered on California, Omland suggests.

Then, as the climate warmed, ravens from Asia may have recolonized the north.

"A scenario like this would be consistent with the pattern we found," Omland says. But it doesn't explain why the California ravens have remained genetically distinct.

Any barriers that kept the northern ravens and their genes out of California during the Ice Ages would seem to be long gone.

"Like all fun science," Omland says, the ravens research "raises more questions than it answers."

It could be the California birds are uniquely adapted to a desert habitat. All of their DNA came from birds sampled in the Mohave Desert, but further studies are needed to find the true limits of their range.

Or, it could be their adaptability. Most ravens are aloof birds of the wilderness. Those in California, however, are happy around people, and especially drawn to their garbage and roadkill.

No parallel to football players there. But what about Omland's orioles?

Much like their baseball namesakes, Baltimore orioles have suffered of late. Their statistics are in decline, and for a time they were all but lost amid confusion over just who they really were.

In 1973, the American Ornithologists' Union noted that the Baltimore oriole, an Eastern bird, and the Bullock's oriole, found in the West, were interbreeding where their ranges meet in the Great Plains. So the AOU decided to lump the two species into one. They called it the northern oriole.

In 1995, however, after considering additional criteria such as plumage and behavior, the authorities reversed themselves and split the birds into two species again.

Omland's genetic studies have since shown differences of 4 percent in their DNA, suggesting they, like the ravens, had evolved separately for perhaps two million years.

When he compared the Baltimore and Bullock's orioles' DNA to samples from all 25 species in the Americas, they proved to be more closely related to two Mexican species than to each other - just .5 percent different.

Both species probably split off from their Mexican forebears a few hundred thousand years ago.

"That had never been suspected," Omland says. "The fact that they can get together and interbreed on the Great Plains is really pretty surprising."

It turned out, after sequencing DNA from 45 oriole species and subspecies found in the Americas, that all of them trace their ancestry back to 10 species in Mexico - evidently the birthplace of the entire clan.

Omland plans more detailed studies of Baltimore orioles and their Mexican kin. "We're trying to home in on whether they separated maybe as recently as the most recent glaciation," perhaps as little as 10,000 years ago, he says.

It may even be possible to reconstruct the appearance of the original orioles, based on the characteristics of those whose genetics place them at the "root" of the orioles' family tree.

Now, if the football Ravens could only overrun California, and the baseball Orioles could reconstruct a winning team, all of bird-dom would rejoice.

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