Petra Mathers, author of children’s stories; at 78

Petra Mathers, a Germanborn children’s book illustrator and author whose kindly, often bumbling animal characters were nonetheless quietly heroic and often risked much for love, died Feb. 6 at her home in Astoria, Ore. She was 78.

Patty Flynn, her executor, said Ms. Mathers and her husband, Michael, a photographer, who was 79, took their own lives. There did not appear to be an obvious health concern that precipitated their act, although they had often told friends that they could not live without each other. They were a private, devoted couple, and the timing of their deaths remains a mystery.

With spare, naive images rendered in ink, pencil, and watercolor, Ms. Mathers’ stories — whose subjects included a soulful museum guard (an alligator) who falls in love with the subject in a painting (another alligator), and a warmhearted chicken named Lottie and her best friend, Herbie, a duck — were just as sparely written, but imbued with sly humor and wit, captivating both her 8-and-younger audience and their parents.

“Here is the story of a chicken who flees the coop,” Carol Brightman wrote in 1985 in a New York Times review of Ms. Mathers’ first book, “Maria Theresa,” a tale of a dreamy fowl who has all sorts of adventures. “You know the type. No ordinary laying hen, this one sometimes stops ‘in mid-peck as if listening to faraway voices.’”

Ms. Mathers’ prose and her “flat, old-fashioned cutout surrealism” combined “an attention to both the commonplace and the arcane which marks the best of children’s literature,” Brightman wrote. “The book’s final tableau of circus folk (and fowl) dancing the Tango Argentine outside Miss Lola’s Airstream is a triumph of this vision. What else but a hopelessly romantic chicken, one that never forgets to lay the morning egg, could bring us such a show.”

Other reviewers compared the loopily unfurling tale to a Federico Fellini film.

Ms. Mathers had already written four books when she began her Lottie series in the late 1990s. An interviewer asked her: Why focus on chickens? “I can make them move, draw them to express feelings,” she replied, adding: “Lottie is my role model. Even though it seems that I am inventing her, she already exists in all of us when we are at our best.”

“When Aunt Mattie Got Her Wings” (2014), Ms. Mathers’ last book, foreshadowed one of her last acts, a decade later.

Mattie is Lottie’s beloved aunt; here she is 99 years old, and dying, and Lottie travels to the hospital to say goodbye. Aunt Mattie wakes up to greet her. “They’re expecting me upstairs, but I told them I was waiting for you,” she says. “Oh Lottie, what fun we’ve had.”

And off Aunt Mattie goes. It’s not clear where, but there’s an airplane waiting for her — a flight on “Out of This World Airlines” — and lots of other chickens. Everyone looks pretty happy. Back home, Lottie finds a note waiting for her.

“By the time you read this I will be dead,” it says, “and I imagine you’re feeling a little down in the beak. That’s why I’m writing this letter. I’ve had a long and happy life doing what I love best.” Aunt Mattie adds, “Now it’s time to make room for someone else on this earth.”

Petra Tollens was born March 25, 1945, in Todtmoos, Germany, a small town in the Black Forest, and grew up first in Stuttgart and then in Wiesbaden, where her father, Ernst Tollens, was a representative for a Champagne firm; her mother, Carola (Glass) Tollens, worked part time in an office.

“I was always drawing for as long as I can remember, but not well,” she told Dilys Evans, author of “Show and Tell: Exploring the Fine Art of Children’s Illustration” (2008). After high school, she worked in a bookstore and for a publisher of encyclopedias before moving to Oregon in the mid-1960s with her husband at the time, Eberhard Richter. She worked as a server and painted, exhibiting her work in local galleries. She later met Mathers in what was by all accounts a coup de foudre; they were married in 1980.

Over the decades, Ms. Mathers illustrated more than 30 children’s books — a process she described as “visiting,” requiring “a certain politeness, consideration and modesty” — and wrote 10 titles of her own.

Ms. Mathers leaves her son, Tillman Richter; a grandson; and her brother, Gero Gerweck. Her marriages to Richter and David Spence ended in divorce.