"His work partner scrambled down the slope to access him and he found him alert and conscious and obviously in a significant amount of distress," said Mike Leum, a member of the Montrose Search and Rescue team.
Feenstra used a satellite phone to call for help and a Los Angeles County Fire helicopter spotted the two men shortly thereafter. But heavy power lines prevented responders from using a hoist system to lower a medic down the embankment to them, said L.A. County Fire Inspector Matt Levesque.
It took responders from Montrose Search and Rescue and L.A. County Fire several hours to reach the site on foot. San Miguel's body was recovered at about 3 a.m. on Thursday, officials said.
"It was in a canyon bottom north of Mt. Wilson in very rugged and steep terrain," Leum said. "It took ropes and our winch truck to even access the victim. And unfortunately, at the time that Montrose Search and Rescue and County Fire personnel got him he was pronounced dead at the scene."
News of the death sent ripples through the California birding community. In an e-mail Thursday, Kimball Garrett, an ornithologist with the Natural History Museum of Los Angeles who knew San Miguel for 40 years, described him as an enthusiastic and accomplished ornithologist.
"Those who knew Mike well, and a great many who didn't, were keenly aware of Mike's tireless work for bird and wildlife conservation," Kimball said. "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 preseved or restored for birds and birders."
San Miguel served on the board of the Western Field Ornithologists and on the California Bird Records Committee (CBRC), according to Kimball. He helped produced the committee's book, "Rare Bird of California," and contributed large amounts of field work to the Los Angeles Breeding Bird Atlas and eBird.org, an ornithology database.
"He loved being in the field whether alone or with his many friends, and he enjoyed learning something new every outing," Kimball said.
San Miguel is survived by his wife Gayle, children Michael and Lisa, and grandchildren Jake and Alex.