At Baltimore's new baseball stadium, the Orioles won't je the only birds. The bats won't all be Louisville Sluggers. And the wildlife won't be restricted to the $4 seats.

Naturalists say the new ballpark is likely to shelter a variety of urban fauna. It may be a home where some big brown bats roam, where a few nighthawks, sparrows, ring-billed gulls, crows, ravens, rats and house mice forage for bugs and pretzels.

Maryland Stadium Authority officials are confident they can keep these critters under control.

Naturalist( say some of the wildlife the ballpark may attract, such as the insect-eating bats, will be beneficial.

But some fear one animal may become a major headache: the urban-dwelling pigeon, also known as the rock dove.

An estimated 250,000 pigeons roost, nest and mess in downtown Baltimore, and bird specialists say a fair number may decide to relocate from their current haunts, such as badly splattered City Hall, to the gleaming sports palace at Camden Yards.

Pigeon byproduct is an aesthetic nuisance, but it can become more than that.

In large concentrations, one veterinarian said, it can spread bacterial diseases and cause nasty infections.

"There's no question that the new stadium will have far more pigeons than the old stadium does," said John Barber, USF&G;'s resident ornithologist. "The reason is the proximity to downtown, which has an enormous pigeon population. And also the architecture of the stadium."

Pigeons, he said, are likely to love the structure's numerous exposed steel girders and pipes, elaborate ironwork and concrete platforms.

Many of these ledges are located in roofed arcades, providing the birds with coveted shelter from predators.

Mr. Barber said the USF&G; building's pair of peregrine falcons, Blythe and Beauregard, have already begun snatching pigeons from the skies above the new