Even if he didn’t say so – repeatedly – it is obvious that Bruce McMillan is still a kid at heart.

He bounds from room to room in his home in Shapleigh – much of which he built himself – showing visitors his treasures: paintings, rocks and magazines he brought from his latest visit to Iceland. A quick story accompanies each item, including his airy wooden abode. The house, southwest of Portland, he constructed with skills acquired in his sixth-grade shop class at the Garland Street School in Bangor. The Icelandic gossip magazine features his translator leading groups of oldish women on trips to Greece. The round rock was blown through the air by an erupting volcano. And the painting of the rotund woman reclining in the blueberry fields? That’s his girlfriend.

Telling stories – some factual, some fun – comes naturally to McMillan. This, along with photographing nature and children, also has become his life’s calling.

“Not a clue,” he responds when asked if he ever thought he’d spend his life writing books and taking pictures.

“I love books. I’m lucky I get to do something I love,” he said, showing off a copy of “Grandfather’s Trolley.” Former first lady Barbara Bush autographed the copy she had recently read aloud at the Kennebunkport Trolley Museum.

The pictures came first. McMillan’s father belonged to the Boston Photo Club and exhibited his pictures. The younger McMillan’s first piece of photo equipment was a pinhole camera he made himself. The first picture he ever sold was of a now-famous house on Walker’s Point in Kennebunkport. A Bush relative saw it hanging in a coffeehouse and asked for six copies.

Then came the animals. McMillan studied biology at the University of Maine, where he also took a business law class from a young instructor he was sure would go places. The teacher was William Cohen, now a former defense secretary and U.S. senator.

Then came the writing. After graduating from college, and working as a producer and director at a Maine public television station, McMillan was the caretaker of McGee Island off the coast of Port Clyde where there was neither electricity nor running water. In the summers he tended the island, and in the winters he taught himself to write.

He practiced for two winters and at the end of his stay he wrote his first published work, an article for Down East magazine called “Our Winters on a Maine Island.”

When it was time to leave the island, he had outlined what was to become his first book, “Finestkind o’ Day: Lobstering in Maine.” It was photographed on McGee and featured his son, Brett.

While many of McMillan’s books are of the familiar Maine landscape, he’s traveled much farther afield of late to places such as Alaska, Antarctica and Iceland.

To date, he has published 42 children’s books, many of them award-winning.

His latest mirrors a childhood favorite of McMillan and many other youngsters. Growing up in Boston, before his family moved to Bangor and then Kennebunkport, McMillan could trace the route of Robert McCloskey’s ducklings through the city’s common. As for many children, the classic “Make Way for Ducklings” was his favorite book.

So, it is somewhat ironic that decades later, McMillan, too, did a book about ducks. This one, however, is set in McMillan’s new favorite place to visit – Iceland.

“Days of the Ducklings” is the story of a young Icelandic girl, Drifa, who watches over eider ducklings as they grow up on an island 75 miles south of the Arctic Circle.

She and her family painstakingly return the birds to an island they had largely abandoned when it was used for farming. Drifa stealthily removes eggs from nests on nearby islands until she has gathered more than 200. She watches as ducklings hatch from the eggs. She feeds them, cleans up after them and leads them for walks around the island. She does not hold them because they must remain wild birds.

At the end of the summer, the ducklings swim out into the ocean in search of small shellfish and crustaceans to eat. They no longer sleep in the grassy pen Drifa made for them. They are becoming wild ducks when she returns to the mainland in August.

The eiders must be taken care of, McMillan explained in his sunny kitchen, because their soft down is an important component of the Icelandic economy, which is based largely on fishing and other natural resources. Soft eider down is prized for pillows, comforters and clothing.

Bouncing around his kitchen as if bobbing in the water, McMillan recalled making the book. His legs encased in hip waders, he was waist-deep in the water. Holding a camera just above his waist, he demonstrated how he snapped pictures of the small ducks as they swam all around him.

He shot 6,500 pictures. Forty-five ended up in the 32-page book.

In another tale set in Iceland, “Nights of the Pufflings,” young children gather up baby puffins that fall from the surrounding high cliffs into the town rather than landing in the ocean.

Too many children’s books, he said, aim to make us feel guilty for “taking up space on the planet.” His aim is simply to get children to appreciate nature, not to glorify it.

He laughs at the fact that people ooh and aah over the puffin book, saying the black birds are so cute.

“They serve puffins in restaurants in Iceland,” he says matter-of-factly. (The meat is oily and not too tasty, by the way.)

“There are millions of puffins there. There are more puffins than chickens.”

In fact, in Iceland people hunt puffins from camps, much like our deer camps.

Capitalizing on people’s love of the birds, McMillan has led several puffin-watching trips to Iceland.

He also shares his love of writing. Several times a year, McMillan teaches a class about writing children’s books at the University of New Hampshire. Two of his former students have published five books of their own.

Asked why he is willing to share his secrets about publishing, McMillan said, “It’s great to see other people succeed. I know the thrill of getting your first book published and it’s just as fulfilling to see it happen to others.”

For more information on McMillan’s classes, books or travels, visit his Web site www.brucemcmillan.com.