I boarded the bright green Maine Brew Bus Sunday with my Peterson’s bird guide tucked into my bag.

I got the book for Christmas in 1979, the same year I took an ornithology class in college and got hooked on birdwatching. Here I was, 37 years later, just a casual birder now, going on a new tour that combines some favorite pastimes – identifying wild birds and downing craft beers at a couple of Maine’s best brewpubs.

The series of tours, “Birds on Tap,” is a collaboration between the Maine Brew Bus and Freeport Wild Bird Supply. The tour I joined, fourth in the series, was “Spring Ducks and Draughts.” We were headed to the Merrymeeting Bay area to look for green-winged teal, northern pintails and other spring migrants that aggregate there to take advantage of the wild rice banquet laid out for them in the mudflats.

Joining me on the bus in Portland were food blogger Kate McCarty (“The Blueberry Files”), who signed up to nurture her growing interest in birding, and her mother, Anne Meadows, who drove all the way from Maryland just for this outing and confessed she was more interested in beer than black ducks.

We rolled out of Portland and headed up Interstate 295 to Freeport, where we picked up the rest of our group, including tour leader Derek Lovitch, a bearded guy in a plaid shirt and jeans carrying a spotting scope. (Turns out I didn’t need my Peterson’s Guide – Lovitch is a walking encyclopedia of ornithology.) Lovitch and his wife, Jeannette, are trained biologists-turned-entrepreneurs who have owned Freeport Wild Bird Supply for 12 years.

“I don’t know birds,” the woman sitting behind me said tentatively.

“That’s all right,” Lovitch replied. “That’s why I’m here.”

I know birds, but not like I used to. The intensity of my interest waned after other members of my family caught the birding bug and turned it into a competition. For me, birding was a way to relax and have fun. I had enough stress in my life in graduate school and, later, working in journalism – I didn’t need the additional stress of being the first one in the family to see a cerulean warbler. And life lists? I hate them.

So Birds on Tap seemed perfect for me. You can’t take birding too seriously if it’s combined with beer.

Our stops were dictated by the tides and tasting room opening times. Birds first, beer later.

‘NO MATTER WHAT, THERE WILL BE BEER’

On the way to our first stop, Mailley Park in Bowdoinham, Lovitch told us that Merrymeeting Bay is one of the largest estuaries in the world and the spot where the Androscoggin and Kennebec rivers meet.

“Most of the ducks that stage – which is migrants stopping for a short term – on Merrymeeting Bay are eating wild rice,” Lovitch explained. “Last fall’s crop, a lot of it would have fallen into the soil. As the ice scoured the dirt, it brought up some more of that rice and wheat seeds and acorns and everything else that ends up in the water.”

After this, I got multiple requests from droll fellow birders to include recipes for roast duck with wild rice in this story.

Next came the requisite gentle warning that we are not guaranteed anything; the number and species of ducks we see, Lovitch said, will be largely determined by the wind, tides and birders’ luck. “The good news is, no matter what birds we look at, there will be beer at the brewpubs,” he said.

At the park, we immediately spotted a pied-billed grebe. Lovitch lined up some common mergansers in the scope – diving ducks that have plumage like “punk rock hair-dos” and are among the earliest arriving spring migrants in the region.

We also checked out some double-crested cormorants lined up on a log, wings spread.

“One of the myths of cormorants is they are holding wings open to dry,” Lovitch said. “They have a slightly different feather structure than waterfowl. They press their feathers down and push the air out in order to dive really quickly, and it’s thought that makes them wet. That’s actually not true. But it does allow them to get colder quicker. They lose that insulating layer of air between the water and their body. So they’re not actually drying off, they’re simply warming up.”

At the mouth of the Abagadasset River along Browns Point Road, green-winged teal were scattered across the mud flats. There were northern pintails and a lot of chocolate black ducks. Suddenly, a group of ducks flew off, trying to escape the clutches of a bald eagle looking for lunch at this spring duck buffet.

A bit later, Lovitch peered through his scope again and asked “Who wanted to see a wood duck?”

“Me! Me! Me!” all the birders answered like kindergarteners.

SCIENCE AND SUDS

Not all of the birders were experienced, and that’s the way Lovitch wants it. The tours are meant to be accessible to anyone who is interested in learning more about birds and wildlife conservation. Lovitch also happens to be a beer lover.

Freeport Wild Bird Supply is located next door to Maine Beer Co. When Lovitch wanted to increase attendance at book signings, he started hosting them there, thinking it would be a less intimidating environment for non-birders. It worked.

Then a professor approached him about co-sponsoring a lecture series on ornithological topics at a local brewery for the same reason – to make “very scientific topics” more approachable. Rising Tide Beer Co. in Portland agreed to host a lecture on a Tuesday night, hoping for 20 to 30 people. Sixty-eight people showed up. Average attendance has been 70, even for topics like “Satellite tracking of migrant shorebirds as indicators of ecosystem health.”

“The pressure of going to a lecture on such an intense topic was taken off by the fact you’re at a brewery,” Lovitch said. “I mean, who takes it that seriously, right? So that really opened up a diverse audience for some really cool, important conservation topics. The success of that clearly showed that my wife and I are not the only ones who like beer almost as much as birds.”

Then one day Lovitch was at his store and saw the Maine Brew Bus pull into the parking lot next door, and “Birds on Tap – Road Trip!” was born. The first trip, “Shorebirds and Beer,” sold out in two weeks.

The trips attract people like Joyce Blakney of Winslow, an avid birder who drove 45 miles with her friend Sherry Brown to ride the bus.

“It’s a nice combination of two very different worlds,” Blakney said. “It gives everybody a relaxed feeling, a little more camaraderie. Birding can be a little competitive, and this takes that away. I’ve been around birding groups where everybody just wanted to have the best binoculars, you know?”

Brown lives on a farm in Benton and has lots of bird feeders, but no idea which birds visit them. She agreed to come along on the tour because “it’s OK not to know very much.”

“I don’t know anything. I know that birds fly,” she joked. “I can spot a mallard.”

TALK ABOUT A NOTABLE SIGHTING

The sight of binoculars and spotting scopes pouring out of the Maine Brew Bus draws the curious like a birder to an unidentified warbler perched in a tree. At the Abagadasset, a car slowed down to rubberneck. Farther down Browns Point Road, we got out of the bus to walk along the road and check out the ponds and fields, the bus rattling along behind. It must have been an odd sight: Kate Cutko, the local librarian, came running out of her house, calling “I have to ask! I just have to know!”

Cutko said when she saw us through her window, she thought perhaps some “desperate” Audubon group had rented the bus to drive them around. She told us about an active eagle’s nest at the end of the road and recommended The Old Goat, a “great little pub” in Richmond where she once hosted a book signing for Josh Christie, who writes about Maine beer.

Back on the bus, Don Littlefield passed out kale-and-feta hand pies from Ten Ten Pié in Portland, the Brew Bus’ “baking partner.” Littlefield – UPS supervisor by night, Maine Brew Bus driver and general manager by day – shared lecture duties with Lovitch. At our beer stops, Littlefield talked about styles of beer and the history of the brew pubs. He also kept us on schedule.

At Oxbow Brewing Co., nestled in the woods of Newcastle, the gang enjoyed two-ounce tastings of Space Cowboy, Bandolier and other Oxbow beers, the cost of which is covered in the $65 tour tickets. We got a tour of the brewery and learned the difference between a farmhouse ale and a saison.

Heading south again on the bus, Lovitch quizzed the birders about their favorite beers from Oxbow, and talked about styles of beer as if they were species of birds. We made one last “bonus birding stop” at Bay Bridge Landing Wetlands Park in Brunswick, where we hoped to see a Eurasian wigeon but instead got a stellar glimpse of an osprey that had probably just returned from its winter home in Venezuela.

We finished up at Ebenezer’s Brew Pub, home of Lively Brewing Co., where Littlefield – the Ryan Seacrest of Birds on Tap – alternated holding court with Kelso Walls, the assistant brewer and bartender.

Walls explained the difference between ales and lagers, then introduced the first beer for sampling – a refreshing German-style pilsner called Hasenjager. Next came Holy Candy, a Belgian-style ale in the Trappist tradition – strong, malty, alcoholic and slightly sweet – and “This Juice,” a fruity, hoppy IPA.

Margaret Reimann of Cumberland sat next to me and declined all of her samples, passing them along to other members of the group. Reimann doesn’t drink beer, but she’s been birding for about six years and is a regular on Lovitch’s free Saturday morning bird walks. She signed up for this tour (and an earlier one) to discover new places to take out-of-town guests.

“The whole history of the brewing industry in Maine is interesting to me,” she said, “and because I do entertain a lot I’ve got some cool places to bring people that are off the beaten path.”

Lovitch tallied the bird counts, and on the way back to Freeport estimated that we saw 1,000 black ducks, 200 green-winged teal, 100 mallards, 24 northern pintails and 12 common mergansers, not to mention six bald eagles and several other species. He asked the group to name their favorite bird, their favorite beer, and their favorite moment of the day.

Anne Meadows, soon to be migrating back to Maryland, said: “I liked all the beer. I have no complaints.”