TAMPA — Mary Keith peered through her binoculars. A rapid, high-pitched squeak — "wee-see, wee-see, wee-see" — had caught her attention.
She and fellow bird-watcher Mary Pfaffko were sure it was a black-and-white warbler.
"It sounds like shoes on a gym floor," Pfaffko said.
Sure enough, they caught a glimpse of the little bird as it flitted through the trees Saturday morning. Pfaffko, 32, pulled out her notebook and added another hash to the tally, the count that will be compiled with international numbers collected during the Audubon Society's 110th annual Christmas Bird Count.
This citizen-collected data provides insight on species trends. In Tampa, for example, the number of mallards has remained steady, but fewer blue-winged teals and northern shovelers have been spotted in the past decade.
Keith, 62, said the greatest local losses have been in wetland and grassland species. Development is to blame, she said, because it's decimating the birds' habitat. She likes to take people bird-watching so they'll care.
"They see the birds, and then they're interested in saving the wetlands, the park and the trees," she said.
But not all population gains among birds are for good reasons. At Lettuce Lake Park near Tampa, a group led by Keith spotted a lot of limpkins, a brown crane-like bird that got its name from what seems to be a limp when it walks.
Limpkins eat apple snails, and the local population boom is due to a recent increase in an invasive type of apple snail in the park, Keith said.
"They're usually much harder to find," she said.
The two Marys started counting birds at 5:30 a.m. Keith started with two pairs of gloves to keep warm. They had to get going early, she explained, to hear the owls.
Later in the morning, she shed one pair and met up with more local bird lovers. The group split up: Some searched Tampa lakes for ducks, and George Kaye, 66, of Tampa, joined Keith and Pfaffko along Lettuce Lake's boardwalks.
He wasn't as quick as Keith, who has a lifetime of bird watching behind her. ("My parents were botanists," she explained. "I grew up in the woods.") But Kaye was the first to spot an osprey eating a fish on a branch of a towering cypress tree.
"Mmmm, good," he said, holding up his binoculars. "Tasty fish."
The three quietly walked along the boardwalk, calling out bird names to Pfaffko whenever they saw or heard a bird.
Turkey vulture. Wood stork. Carolina wren.
A family walked up from behind, braving the cold with their two young boys.
"Do you see that bird?" the dad asked.
It was a white ibis.
Keith is used to the common white ibis. But she usually sees more egrets and herons along the water in Lettuce Lake Park. They might be farther back in the trees, out of view, because of the high water level, she said.
"They don't always cooperate," Kaye said.
And the birds don't always follow what birding books say about them.
One time, Keith saw an owl catch a fish that was so big it had trouble dragging the fish out of the water.
"Owls aren't supposed to go fishing," she said. "But that bird never read the book. It didn't know."
Jessica Vander Velde can be reached at email@example.com or (813) 661-2443.