The wild fox population on Santa Catalina Island is so robust that biologists said Tuesday they may seek to have the small animals taken off the federal endangered species list next year.
The number of Catalina Island foxes -- a subspecies found only on the 75-square-mile island 22 miles off the coast of Southern California -- topped out at 784 in a new count, a remarkable rebound for animals that were nearly wiped out a decade ago after an outbreak of distemper possibly introduced by someone’s pet.
“These numbers are fantastic news,” said Julie King, senior wildlife biologist for the Catalina Island Conservancy.
Rain -- and a lack thereof -- contributed to the population growth, King said.
“In 2007, we had an extreme drought with less than 3 inches of rain,” she said. “As a result, mule deer were dying in great numbers, and the foxes were able to scavenge off the carcasses. By the time breeding season arrived in 2008, we literally had obese foxes, and females in such good condition that they were having larger-than-normal litters.”
In addition, 2008 was “a good rain year, so the rodent population exploded,” she said. “The mice were convenient to-go packages of protein for females to retrieve and feed to their pups.”
About 1,300 foxes once lived on the island. The population had crashed to roughly 100 by 1999, when the conservancy and the Institute for Wildlife Studies launched a $2-million recovery program that included vaccinations and a captive breeding facility.
In 2004, the U.S. Fish and Wildlife Service listed the fox as endangered.
“For a small conservancy to bring a species back from the brink of extinction to a stabilized, growing population in less than 10 years is no small feat,” said Carlos de la Rosa, chief conservation and education officer for the conservancy. “The foxes will be starting their breeding season in the next few weeks, so you will probably start seeing more pairs of foxes than singles on the roads during February and March.”
On Tuesday afternoon, conservancy biologist Calvin Duncan and volunteer pilot Mike Sheehan conducted an aerial survey of the island’s 56 foxes outfitted with telemetry collars, which emit a rapid-fire pinging sound if an animal has not moved for 12 hours.
After an hour of flying about 2,500 feet above rugged island terrain, Duncan gave a thumbs up and said, “We got everybody. All 56 are accounted for, and there are no fatalities.”
The foxes are trapped once a year and inspected for any illnesses, including an unusual ear cancer that recently began showing up in older foxes. “We want to keep them as virus-free as possible,” Duncan said.
Air and ground observations suggest the omnivorous 5-pound foxes are faring well, feeding at night on cactus fruit, berries and insects, scurrying through shrubs and ravines, and establishing territories.
The island’s captive breeding program ended in 2004. But the foxes’ problems are not over. Today, the primary cause of death among foxes is “road kill,” Duncan said. “We’ve got 4,000 people living in Avalon, and driving all over the island.”
The conservancy’s fundraising efforts have fallen $150,000 short of the $222,000 needed to sustain the fox recovery effort through the end of the year.
All field activities, equipment, radio collars, vaccines, medications, fuel, vehicles and seasonal staff are funded through grants and donor contributions, King said.
“We’re reaching out to people interested in contributing,” she said. “A radio collar costs $250, a vaccination is about $10. These costs add up quickly.”