VERONA – The Waldo-Hancock Bridge is for the birds – and two pairs of persistent ospreys aim to keep it that way.

The stubborn, feathered couples, which for several years have been living atop the twin towers on the bridge, have not taken kindly to state efforts to evict them.

For the past two weeks, the birds have been trying to build new nests on the towers despite the deterrents that crews from the Maine Department of Transportation have put up there in an effort to get them to move elsewhere.

The DOT is in the middle of a multiyear, $25 million rehabilitation project on the bridge. Most of the work so far has been on the supports underneath the bridge, well away from the osprey nests.

But for the next two years contractors will be working on the main cables and the suspender cables, which necessitated moving the birds for their safety as well as for the safety of the workers, according to Scott Rollins, DOT project manager for the bridge project.

“We don’t want them swooping down on the workers there,” Rollins said. “Someone could get hurt out there.”

The osprey is a large raptor also known as a fish hawk because of its main diet. It can weigh about 3 pounds and has a wingspan of 51/2 feet. A breeding pair mates for life and returns to the same nest area each year. Ospreys can live up to 25 years.

In February, DOT crews removed the established nests from the towers and relocated them on platforms atop 40-foot poles set along the shore of the Penobscot River near the bridge, hoping the birds would relocate to the new site.

Working with animal control officials with the U.S. Department of Agriculture, and with a permit from the state Department of Inland Fisheries and Wildlife, the DOT installed a plastic and stainless steel gadget called a “daddy longlegs” that spins in the wind near where the nests had been.

“We were hoping to deter them from rebuilding there,” Rollins said Wednesday. “But within the past week or so, they’re still trying to rebuild the nest up there.”

The DIF&W permit, which allows the DOT to move the ospreys, stipulates that once the birds establish a nest on the site and lay eggs, their nests cannot be moved.

“If they get to that point, we can’t touch them,” he said.

There are two pairs of ospreys trying to re-establish nests, one pair working on each tower, Rollins said.

The towers rise 200 feet above the Penobscot River.

DOT crews have climbed to the top of the towers and removed the sticks the ospreys have placed there, but the birds keep coming back.

“They’re being very persistent,” he said. “We’re hoping we can be more persistent than they are.”

Phil Roberts, DOT resident manager for the bridge project, and crew member Rick Gebert have been climbing to the top of the towers daily since the birds returned last week. On Wednesday, Roberts removed eight to 12 sticks from the west tower, a little less than on Tuesday, a little more than the day before.

On one trip, he said, they found that the birds had brought up some of the bailing twine from the hay used to mulch the area around the alternative nest poles the department had set up on the shore.

“At least they used something we put out for them,” he said.

Within a half-hour after Roberts and Gebert had descended from the tower Wednesday, the ospreys were back on the tower, apparently ready to start again.

The ospreys’ stubbornness is not surprising, according to biologist Lindsay Tudor of the DIF&W.

“Osprey can be very tenacious about where they want to nest,” Tudor said Wednesday. “It’s part of the whole pair-initiation process, working together to build a nest.

“And when they’ve found a nest where they’ve pulled off young, they become even more tenacious. They know it’s a successful site.”

If the department can put up a deterrent that will keep the osprey from establishing a nest, the birds eventually should move to another site, especially as they get closer to laying eggs, Tudor said. There’s no reason to think that an alternate site would not be successful, meaning that they would produce young.

Last year, a bridge project in Arrowsic relocated a pair of ospreys that adapted to their new home and had a successful year, she said.

Once the bridge project is completed, the ospreys would likely return to their preferred nesting site, she said.

DOT officials are trying to match the birds’ determination and will be back on the towers today to try to rig a chicken wire tent over the nesting site.

“It should keep the birds off it,” Roberts said.