Marjorie Yasue Fern Ziegler, a passionate advocate for Hawaii’s wildlife and wild places, died unexpectedly at age 62 at her family’s home Wednesday, according to the Conservation Council for Hawaii.

Raised with a love of nature, Ziegler served as the council’s executive director since 2003 when she became its first full-time staff member. Before that, she worked as a resource analyst for 14 years for the Sierra Club Legal Defense Fund, now known as Earthjustice, protecting endangered species and ecosystems.

“Marjorie was as reliable as she was brilliant — so of course, when she spoke, people listened,” said Wayne Tanaka, president of the board of the Conservation Council for Hawaii. “From legislators to agency personnel to folks on the ground, Marjorie was the No. 1 go-to person for advice, a fact check or, if you were lucky, an ally in your fight.”

Ziegler suffered a heart attack a few years ago, and her health had declined over the past year but her death came as a shock, said her close friend Doug Lamerson. “She passed in her sleep,” Lamerson said. “I think her heart just quit on her.”

“Despite her fierce public persona and advocacy, there was really a very soft person behind there,” he said. “You would see it expressed with animals, and she was really, really good with kids.”

Born on Jan. 14, 1956, in Berkeley, Calif., Ziegler grew up in Kaneohe and credited her parents with connecting her to nature from the start. Her father, Alan, directed Bishop Museum’s Division of Vertebrate Zoology, and her mother, Kaye, who hailed from Kyoto, Japan, loved animals.

Ziegler grew up with an assortment of pets, both domestic and semiwild. The family freezer also sometimes contained specimens that her father had collected and stored temporarily, clearly marked “Not for consumption.”

She attended Windward public schools from Kapunahala Elementary through Castle High, followed by Windward Community College. Ziegler worked as an archaeological assistant at Kualoa Regional Park and a recreation assistant at Kailua District Park.

She went on to earn a bachelor’s in geography from the University of Hawaii at Manoa. Lamerson, a close friend since their days as UH classmates, said it took time for her to take on the mantle of an outspoken advocate.

“I remember her being terrified at the prospect of having to give a presentation in one of her classes,” he recalled. “Nobody who knows her today would imagine that, for her to lack confidence in that way.”

Ziegler described her father as “my best friend, mentor and inspiration.” She followed his lead and mentored a generation of conservationists in Hawaii. She was known for bringing people together, forging coalitions and approaching issues pragmatically.

“She was very culturally akamai for someone who was not Hawaiian,” Lamerson said. “She was very sensitive to the Hawaiian culture as well as the natural environment, and that made her effective.”

Ziegler built up the Conservation Council’s educational and advocacy programs as well as its membership, which now tops 5,000 members. The nonprofit organization is the state affiliate of the National Wildlife Federation.

“The matriarch of Hawaii’s environmental movement and the architect of the Conservation Council for Hawaii has passed on to live in the arms of the earth she so loved,” her friend Rosemary Alles wrote Monday in a post on Facebook. “Your fierce love for our planet, all its creatures and its people will rest and rise with me like the constant blue that reaches for and then breaks on our Hawaiian shores.”

The Conservation Council for Hawaii’s board of directors has established a Marjorie Ziegler Legacy Fund to further her work to restore and protect Hawaii’s indigenous plants, animals and habitats.

“Her lifelong commitment to the environment was unquestionable,” said Randy Bartlett, interagency coordinator for the Hawaii Invasive Species Council. “From the classroom in our college days, until the last weeks of her life, she never stopped advocating for native species biodiversity and conservation.”

Along with her mother, Ziegler is survived by her brother, Walter. Services are pending.