At Baltimore's new baseball stadium, the Orioles won't be 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. Naturalists 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 can become more than an aesthetic nuisance. 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 stadium.
Bruce Hoffman, executive director of the stadium authority, admitted to being mildly concerned about the pigeon question.
"I don't want the old train station or the stadium to get covered with pigeon debris," he said. But, he said, "to date, I have not seen any sign that they're around."
Most pigeons will be scared off by the crowds, he said. After games, he said, cleaning crews will quickly scour the stands of food scraps. No food, no birds, he reasoned.
Mr. Barber agreed that quick cleaning would help, although he recommended other measures as well -- including the relocation of any pigeon eggs laid in stadium nests.
If pigeons do flock to the stadium, what can be done?
Stadium Authority officials said they have looked at buying devices that emit an ultrasonic pigeon distress call that's supposed to terrify pigeons, but that humans can't hear. Mr. Hoffman said the authority might, for example, buy 10 of the $400 devices and scatter them around the structure.
"Very ineffective. Birds get used to it," said Heidi Hughes, president of Wild Bird Co. of Rockville.
Poisons are out, Mr. Barber said, because they can kill other animals.
A widely sold glue that turns ledges into flypaper for pigeons is inhumane, Ms. Hughes said, since the stuck birds suffer until they starve or freeze.
Ms. Hughes suggested that stadium officials purchase commercially made mats with steel spikes and place them on the beams and pipes, preventing pigeons from landing.
Spikes? The job would be enormous, Mr. Hoffman said. "You can't imagine how many ledges there are beneath that sunroof," he said.
Dr. Michael Cranfield, veterinarian at the Baltimore Zoo, said the zoo uses spikes to discourage roosting in some locations.
Zoo workers also trap pigeons, which are then relocated or fed to predators, including falcons.
Dr. Cranfield said the raccoons and wild foxes that hang around Druid Hill Park and the zoo probably won't show up at the stadium. "There's not enough green area for them to survive down there," he said.
Rats and mice, which for centuries have noshed on human cuisine, probably will be attracted to the new stadium despite the best efforts of the cleanup crews. But Mr. Hoffman said exterminators have been baiting traps for these animals since demolition on the project began. "This was a terrible rodent site when we took it over," he said.
Gulls may also hunt for scraps at the stadium. But these shorebirds prefer a waterfront nesting site.
Predators are also expected. "Oftentimes at Memorial Stadium, I have seen common nighthawks, and swallows and bats feeding on the insects around the lights," Mr. Barber said.
Like its predecessor, the new stadium probably will attract a few bats -- perhaps the Big Brown Bat or the Little Brown Bat, the two most common species in this area, said Tom Valega, head of the American Bat Conservation Society in Rockville.
Mr. Valega said bats are generally harmless and are ravenous eaters of insect pests.
Fans who spot a bat in the upper deck lights, he said, "should sit there and admire it and watch its aerial acrobatics. It's amazing."
Fauna at Camden Yards
Some of the animals likely to be attracted to Oriole Park at Camden Yards include:
* Pigeon or Rock Dove (Columba livia): This hardy scavenger originally nested on cliff ledges in Europe and Asia. Transplanted to the United States, it now thrives on buildings and bridges in central cities in the lower 48 states and southern Canada. The birds make a guttural cooing sound. Females lay two white eggs in nests lined with sticks and other debris. Efforts to eradicate the bird, often considered a pest, have met with widespread failure.
* Big Brown Bat (Eptesicus fuscus): A copper-colored animal commonly found in Maryland and throughout the lower 48 states. This hardy animal, which can tolerate extreme cold, is one of the few to spend the winter in northern cities and often nests in buildings. These bats are believed to be among those spotted feeding on insects attracted to the lights of night games at Memorial Stadium. (Bats themselves navigate by echolocation, similar to sonar, and don't need lights.) Bat specialists say these creatures are generally harmless, despite the fear they sometimes inspire.
* House mice (Mus musculus): Found around the world, this rodent is active at any hour, breeds throughout the year, and is a good climber and swimmer. It builds a nest wherever there is a small, protected space. It eats human food scraps as well as paste, glue, soap and other household items. People build better mousetraps because this furry little creature can spoil food and help spread certain diseases.