Michael San Miguel, an ardent conservationist known for his accomplishments in Southern California field ornithology and bird banding, died late Wednesday while conducting a spotted owl survey in the San Gabriel Mountains. He was 70.

San Miguel was traversing a steep canyon along the West Fork of the San Gabriel River when he slipped and fell about 100 feet, said his son, Michael Jr.

Word of the accident spread quickly throughout the Southern California birding community, which regarded the longtime Arcadia resident as a role model and mentor.

"Mike was a decent individual, a tireless conservationist, a local natural history guru and exemplary family man," said environmental consultant Dan Cooper. "He especially loved getting new people into birding and field research."

In a letter to friends and colleagues, Kimball L. Garrett, manager of the ornithology collection at the Natural History Museum of Los Angeles County, described San Miguel as "an extraordinary connoisseur of rare birds" who embarked on "trips all over California to chase them."

"On my countless wonderful trips in the field with Mike, the conversation would inevitably turn, and pretty quickly, to the inexorable loss of bird habitats as urban areas continued to grow and consume the places we enjoyed going," Garrett recalled. "I would gripe and curse and feel generally pessimistic about everything, but Mike had a different and much more effective approach — he got involved.

"If he enjoyed birding in an area, he felt it was his responsibility to work as hard as he could to make sure it was preserved or restored for birds and birders."

Born in Monrovia in 1939, San Miguel was the oldest of 10 children in a family that camped and hiked in mountains throughout the Western United States. He graduated from Cal State Los Angeles, where he earned a degree in civil engineering.

San Miguel had been a passionate bird watcher since the early 1960s, his son said.

"His first passion was birding, followed by his love for the Dodgers, the Lakers and good wine," his son recalled with a laugh.

"My first memories are of being in Dad's backpack while he was running after a bird for a closer look," he said. "Some of the best times of my childhood were watching him net and band birds in the Angeles National Forest: chickadees, warblers, nuthatches and juncos."

For nearly 20 years, San Miguel worked as an environmental engineer for Southern California Edison. He retired from Edison in 1995 but continued working as an environmental consultant.

San Miguel's experience and talent for identifying birds earned him a place for several years on the California Bird Records Committee. He served as president of Western Field Ornithologists from 1999 to 2003 and played an important role in the production of large-scale data gathering projects, including the Los Angeles County Breeding Bird Atlas and the book "Rare Birds of California."

"His efforts for bird habitat at Piute Ponds, the San Gabriel River and so many other areas we take for granted have been heroic," Garrett said. "His battles with agencies that were damaging habitat were fought with fervor but also with grace. Even the Army Corps of Engineers must have had great respect for Mike."

Besides his son, he is survived by his wife, daughter and father.

Instead of flowers, the family has asked that contributions be forwarded to Western Field Ornithologists.

louis.sahagun@latimes.com