The ocean shines in the distance at the Los Angeles International Airport. As airplanes roar on takeoff, a stretch of sand dunes on the property is alive with activity. Butterfly watchers bend close to the ground as, suddenly, a rare flash of sapphire blue appears.
Then another blue speck dances above a sea of white plants.
Just beyond the airport traffic is an oasis for the El Segundo blue butterfly, listed as federally endangered since 1976. The tiny butterfly, unique to Southern California, emerges in its largest numbers at the El Segundo Blue Butterfly Habitat Restoration Area every summer. The airport manages the preserve, which is on airport property.
The butterflies reach their peak flight in midsummer. During their short adult life, generally about a week, blue dots sprinkle the air at the LAX dunes.
The preserve, which spans 200 acres, was designated a nature preserve for the El Segundo blue butterfly and other native coastal dunes species in 1992.
More than 600 species, mostly insects, live there but the El Segundo blue is the preserve’s only federally endangered resident.
“It’s a nice symbol for the dunes,” said Richard Arnold, an entomologist who is a consultant to the airport on monitoring the preserve and butterfly counts. “The butterfly provides a nice surrogate for protection and benefit of all the indigenous plants and animals that occur at the LAX dunes.”
The male’s upper side is its signature blue, while the females are charcoal gray. On the underside, each is dotted with black squares and a line of orange along the border of its hind wings. The butterfly’s wingspan, when fully stretched, is about an inch.
The El Segundo blue butterfly feeds on the nectar of coast buckwheat, then mates and lays eggs on the buckwheat. The eggs become larvae, which turn into pupae by late summer. The blue butterfly can live in its adult state from four days to two weeks, said Eric Porter, an entomologist and biologist with the U.S. Fish and Wildlife Service.
“They can spend their entire life on one particular shrub,” he said. “It’s this unique butterfly surviving in the landscape of L.A. For it to be hanging around is pretty impressive.”
Development had threatened the buckwheat, but restoration efforts by the airport, nonprofits and volunteers over the years have helped the plant and the butterfly return. There were only several hundred butterflies back in 1976, Arnold said.
These days the numbers fluctuate, possibly compounded by the effects of the recent drought, said Peggy Nguyen, preserve manager. The number dipped considerably last year from about 88,000 in 2012 to about 45,000 last summer, she said.
Though the numbers are down, Arnold is not too worried now.
“They have the ability to reproduce fairly quickly when the conditions are right and can recover,” Arnold said.
By the late 1990s, the butterfly was known in three places: the LAX dunes, the Chevron oil refinery in El Segundo and a small spot at Malaga Cove near the Palos Verdes Peninsula.
But there have been reports of sightings in other locations in recent years, prompting scientists to question whether the insect can travel farther than previously believed.
“We now know that they can colonize between suitable habitat,” said Travis Longcore, science director of The Urban Wildlands Group, a nonprofit dedicated to wildlife and ecological protection in urban areas. The group led a restoration of native vegetation in 2004 at Redondo Beach and Torrance, where blue butterflies were reported.
Longcore believes the El Segundo blue numbers at the LAX preserve were probably closer to 20,000 in 2012 and 10,000 in 2013 because of differences in how the counts are done, but agrees that restoration efforts are helping.
Long-term management is important, he said, for the blue butterfly and other endangered butterflies in California. He noted renewed concern about the decline of the once thriving Lange’s metalmark butterfly at the dunes near Antioch.
Besides the loss of native vegetation, unforeseen catastrophes like wildfires, plane crashes and disease always pose a threat to the butterflies and other wildlife at the dunes, Longcore said.
“You can’t just walk away,” said Longcore, also a research associate professor of spatial sciences at the University of Southern California. “Urban nature only survives over time if there are stewards.”
Journalist Marisa Agha is based in Southern California.