The boat moved deliberately and smoothly over the ripples on the surface of the Connecticut River. The people onboard, some holding tight onto binoculars, gazed to the right, to the left and into the milky blue sky.

Then came the exclamation: On the left shore. At 9 o’clock.

Heads swiveled to look.

There it was. A bald eagle. Sitting majestically on a branch. And staying there, as if posing for the assembled on-boat crowd.

This was the first of several bald eagles the group spotted on a press-preview winter wildlife cruise Monday aboard RiverQuest, a ship owned and operated by Connecticut River Museum in Essex.

During these cruises, the public can scan the river skies and shores for signs of eagles and other birds, from grebes to loons, as well as animals like coyotes and seals. The schedule for these two-hour trips kicks off Friday and runs through March 13.

The cruise sets out from the museum’s dock and moseys up to near Gillette Castle and then back again. Those worried about missing out by not noticing something should have no fear: the cruise has a naturalist who is (to borrow a phrase) eagle-eyed and points out creatures of note.

Essex has one of the largest concentrations of wintering bald eagles on the eastern seaboard, according to wall text inside the Connecticut River Museum; as many as 50 bald eagles might congregate along the Connecticut River’s lower 12 miles from January to March.

With waterways tending to be frozen up north, bald eagles like to move to the lower Connecticut River to have access to fish. There are also a dozen or so resident bald eagles between Middletown and the mouth of the River.

Elizabeth D. Kaeser, executive director of the Connecticut River Museum since Dec. 2022, recalled how everyone was talking up the cruises when she arrived at the museum. She was unprepared for how impressive it was.

“I went out on the cruise, and it was a day when there were a lot of eagles. They were all on wing, and they were soaring majestically. It’s remarkable. You’re like, yes, this is why eagles are amazing. They are not like other birds. They are huge and they own the sky,” she said.

They are imposing creatures, about three to three-and-a-half feet from head to tail, and with a wing span of six to seven feet.

In addition, of course, bald eagles are associated with America and this country’s history.

“There is a tie back to the symbolism of this bird that we see. But I think seeing them flying over the Connecticut River is a truly remarkable thing. They really are beautiful, beautiful creatures,” Kaeser said.

Cathy Malin, who is the museum’s director of operations and works on the boat as a crew member and naturalist, said the resurgence of bald eagles is one of conservation’s biggest success stories. More on this later.

As for the cruises themselves, she said, “This is the time of year we get a little bit of cabin fever, and there’s just something special about being able to get out of the house, get outside, and enjoy the river.”

In addition, she said, there are few if any other vessels on the water, and there are no leaves on the trees, so people can see the contours of the land and can more easily spot animals in the trees.

Flying bowling pins and wimpy calls

Malin provided commentary and guidance on Monday’s cruise.

When someone thought they saw an immature bald eagle (bald eagles don’t get the signature white feathers on their heads and tails till they are around 4 or 5 years old), Malin said the bird was the right size but was more likely a vulture because when it held its wings out, it was in a V shape, as is the case with vultures.

She pointed out various other birds besides eagles. She spoke about the three types of mergansers and noted the common merganser is pretty easy to spot in flight because “it looks like a flying bowling pin.” That’s due to their shape, the fact they are white with darker wings, and how they look when they fly, as their bodies stay still and their wings flap like crazy.

At one juncture, Malin brought out a stuffed-animal toy eagle and red-tailed hawk to explain the different calls of each. Movies and TV shows often sub the red-tailed hawk’s call for an eagle, since it sounds much more aggressive and dramatic. By contrast, Malin said, an eagle’s is more “just kind of a wimpy, chirpy kind of call.”

Their ability to travel great distances certainly isn’t wimpy, though. Malin said that one of the eagles that has been a regular on the lower Connecticut River is banded and so is able to be tracked by bird watchers. She showed on a slide where the bird has been spotted, including areas near Springfield, Mass., Tappan Zee, N.Y., and Hawk Mountain, Penn.

Malin and Captain Dan Thompson discussed the histories and aspects of the land along the route, too — for instance, that Selden Island used to be the site of quarries whose stones were used as paving stones in places including New York City. That venture rather abruptly ended when the advent of asphalt made it a much more popular material for roadways.

Resurgent population

How many eagles are spotted on one of these cruises can vary widely, of course.

But there was a time when spectators would have been unlikely to see any bald eagles along the lower Connecticut River.

Malin noted that, for a long time, there weren’t any restrictions on what municipalities dumped into the Connecticut River. Actress Katharine Hepburn, who had a home in Old Saybrook, once famously called the river “the world’s most beautifully landscaped cesspool.”

One of the bigger issues as far as the eagle population was concerned was DDT, which used to be sprayed to kill mosquitos. The problem is, the DDT ended up in fish, which the eagles ate. The DDT the eagles ingested caused the shells of their eggs to be so thin that, when the mother sat on the egg, it would crack.

DDT was banned in the U.S. in 1972, and the Clean Water Act enacted that same year helped to improve the river, over time raising the water-quality rating from a Class D to a Class B.

And, lo and behold, the eagle population began to bounce back.

50 years

In addition to offering winter wildlife cruises, the Connecticut River Museum is marking its 50th anniversary this year.

“We are excited to celebrate, we are excited to bring people to the river, particularly because this is the 50th year we have been telling stories of the river. The Connecticut River Museum seeks to tell stories of the full length of the river, all 410 miles and to cover the 12,000 or so years of history that people have been using and abusing the Connecticut River over time,” Kaeser said.

The museum is aiming to highlight those stories particularly this year. There will be a symposium in June, a block party in September, and everyone is also invited to leave their own stories of the river on the museum’s website.

Kaeser noted that the Connecticut River is a place where people can be with water and be with nature, “which are incredibly restorative and healing.”

“For us at the museum, being a place that creates an access point for that is important, as we attempt to develop the next generation of river stewards, creating opportunities for people of all ages to be able to experience this beauty but also be aware of how tenuous it all is,” she said.

If you go

What: Winter Wildlife Eagle Cruises

On: RiverQuest

From where: Connecticut River Museum, 67 Main St., Essex

When: Feb. 9-March 13; two-hour cruises leave at 10 a.m. and 12:30 p.m. Fridays, 9 and 11:30 a.m. and 2 p.m. Saturdays and Sundays; also 11:30 a.m. March 6 and 13

Cost: $45

Contact: ctrivermuseum.org, (860) 767-8269