STEVENSVILLE -- Dave Brinker could be humming that old Drifters tune, "Up on the Roof."
The ornithologist is on the roof of Thompson Creek Mall hard by U.S. 50 on Kent Island. Not humming, though -- counting least tern eggs and chicks. Overhead, the annoyed parents are wheeling and chittering, their family life temporarily disturbed.
"It's the closest thing to barren sand they can find," Mr. Brinker said as he and an assistant walked carefully along the white-graveled roof, looking at the rocks and under all the heating and air-conditioning compressors and ducts.
Close is right: the beige eggs speckled with black are hard to see among the rocks on the roof. So are the little chicks -- huddled in the gravel here and there, they're the same colors as the robins-egg size eggs they so recently left.
Mr. Brinker, the wetland nongame wildlife project manager for the Department of Natural Resources, and Christine Simoes spent most of yesterday counting birds on roofs in Talbot and Queen Anne's counties. The annual count is part of monitoring the state's least terns.
The tiny bird -- "smallest tern in the world," Mr. Brinker said with paternal pride -- is legally protected in Maryland and classified as a threatened species. It's also an amazingly adaptable little bird: faced with diminishing beach habitat, most of the state's least terns are making do with roofs on schools and malls and other businesses.
Maryland had 456 breeding pairs last year, and Mr. Brinker said he expects to count close to 500 breeding pairs this year.
He and Ms. Simoes counted 136 pairs yesterday morning at Thompson Creek Mall, their first stop in a long day of roof-walking on the Shore.
The state has two other large communities of the little water bird, Mr. Brinker said. One is at a school in Sparrows Point (125 pairs last year, and scheduled to be counted today). The other, on the northern end of Assateague Island, is responsible for the anticipated increase in least terns this year in Maryland.
"For the first time in 15 years, the northern end doesn't have a pair of red foxes," Mr. Brinker explained, characterizing the foxes as "egg vacuum cleaners." The terns lay their eggs directly in the sand, an easy snack for foxes and other animals.
But disease or storms or both hit pairs of foxes that had been residents of the northern end of the Assateague until last year, and the terns figured it out pretty quickly, he said. Now the island houses about 200 breeding pairs of least terns, many new arrivals from Delaware's tern population, he said.
Other sites where terns are nesting on roofs include several schools around the state, a Mercedes Benz building in Belcamp, a Knights Inn in Cambridge and a furniture building near Easton.
The annual count, being conducted this week, is one of several ways the state works to preserve the little bird, whose full name is Sterna antillarum. DNR also works closely with people under the roofs the birds favor, educating the human residents about the birds' habits and needs.
The birds eat fish -- "menhaden, any little fish," Mr. Brinker said -- from streams and tidal marsh areas, such as the one behind Thompson Creek Mall. They nest in colonies (although each pair stays with its own nest) from late April through August, with each nest having one to three eggs.
The state has established a Least Tern Conservation and Education Program to help educate students and others about the birds.
DNR also has put fencing around most of the roofs used by the birds. On a beach, the chicks will run if they're frightened. On a roof, this behavior can be fatal.
"In natural habitats, they stop running when they hit the water," Mr. Brinker explained. On a roof, they fall off. The low wire fences prevent that, he said.
He said the primary way to find least terns is a low flight -- about 100 feet above the roofline -- and look. But it's not possible to do that in densely populated areas, where the terns have congregated in recent years, so he and others in DNR rely on citizen reports.
"I know there's more out there, but I just don't know where," Mr. Brinker said. "We depend on people calling us, saying 'There's a bunch of white birds flying around.' "
The bird is protected under the federal Migratory Bird Treaty passed early in this century. Mr. Brinker said most schools and businesses are cooperative once they understand the importance of protecting their rooftop residents, even if it means rescheduling heating and cooling maintenance of rooftop compressors and vents.