San Francisco Chronicle - (Sunday)
WILD ANIMAL KINGDOM
Wildlife adapted as people stayed at home. But what happens when parks reopen and traffic returns?
At Kirby Cove in the Marin Headlands, the coyote roaming the beach near the Golden Gate Bridge last month was a sign of the times: With many parks and streets empty during the state’s stayathome order, wildlife has been entering places where it was once rare.
The question is this: How will wildlife respond when people return?
The answers are different and depend most on the behavior of park visitors, say the top experts on humanwildlife interaction behavior at the California Department of Fish and Wildlife. Nearly every species, including coyotes, bears, deer and mountain lions, will be affected, they say.
“With the shelter in place, we’re seeing certain species becoming more active,” said Vickey Monroe, the department’s humanwildlife conflicts programs coordinator. “There seem to be fewer reported wildlife conflicts (with people), yet with an increase of wildlife sightings in many areas.
“One of the big causes of mortality for urban wildlife is getting hit by vehicles while crossing the street or highway,” she said. “That is a mortality factor that has been lessened by the decrease in vehicle traffic. Some wildlife rehabilitation centers (for injured wildlife) have reported a reduced volume of calls.”
“This is an unprecedented time,” added Alex Heeren, a research specialist for the Human Dimensions of Wildlife Conservation Unit. “One highlight is that people are much more conscious about food waste; the total amount of trash is less.” That may force wildlife to return to traditional prey and food sources, he said, and not rely on garbage, trash or pet food.
In Yosemite National Park, which has been closed for more than two months, black bears have had to turn to historic food sources instead of working camp sites for goodies left out.
As people begin returning to parks, golf courses and open space reserves with wildlife habitat, what will happen next? Here are the best projections from the two experts:
Coyotes
In San Francisco,
From top: With fewer human interactions, coyotes, like this male in the Presidio, are transforming back into wilder creatures; fewer deer are getting hit by cars; black bear are seeking out natural food sources. coyotes have been sighted throughout much of the city, and are likely pupping this month in the Presidio and nearby closed golf courses.
“There are so many of them living in urban areas, that coyotes can become habituated to humans and lose their natural fear of people,” Heeren said.
With less human interaction and fewer human food sources, coyotes in urban parks are transforming back into wilder creatures, Heeren said. With less contact with people, “there’s a chance they could become more wild and redevelop a natural fear of people,” Heeren said.
To keep them wild, people must keep potential food sources, such as garbage, pet food and their pets, out of range. The coyotes would then instead hunt prey such as gophers, voles, rabbits, squirrels and other small animals.
Black bears For the roughly 500 bears that live in Yosemite National Park, the biggest threat was cars, which have hit 400 bears in the past 25 years, according to park records. With virtually no cars in the park since the shutdown, no bears have been hit.
To keep it that way when the park reopens, rangers say they will set up radar traps for speeders. At the end of last summer, rangers set up wildlife zones with reduced speed limits.
Without campers, picnics or tourists, the bears’ basic behavior has reformed. “Bears habituated to perusing campgrounds for food or garbage have to fall back to their natural behaviors and instincts to seek out natural food sources: grass, small animals, fawns, ants, grubs,” Monroe said.
In bear country across the state, such as Lake Tahoe, it’s a similar picture, Heeren said. “Bears are very sensitive to human food sources,” he said. “If there’s an influx of tourists, people who may not have experience living in bear country, with more trash and food, and how to secure it, the bears would react to that.”
Again, it is up to people to keep the bears wild, they said.
Deer Each year in California, vehicles hit an estimated 10,000 deer. That number is bound to drop, the experts say, with fewer cars on the mountain highways, especially in April and early May during the annual migration of deer herds from the valleys’ foothill country to higher terrain. “Less traffic, less deer mortality,” Monroe said.
For “resident deer,” it’s a different narrative. These deer often spend their entire lives in a 5mile radius near golf courses, in parks and greenbelt, and in backyards.
As coyotes and bears search for food, predation of this spring’s fawns may increase, the experts said.
One sidebar, Heeren noted, is how dogs allowed to run free can play havoc with deer. “They see that dog and they hightail it out of there,” he said.
One of the best examples of how the presence of large numbers of people affect deer is at Foothills Park in Palo Alto, open only to city residents. At dusk in Las Trampas Valley and neighboring Wildhorse Valley, deer often wait until visitors leave to emerge in large numbers. With no people in the park for more than two months, the deer had no reason to wait. Foothills Park reopened in late May and rangers are watching to see the effects.
Mountain lions Monroe called mountain lions “the charismatic apex predators of the landscape.”
The big cats “don’t like people around,” Heeren said. At many parks, they have been getting their wish.
“With the closures, there are huge areas with very few people right now and a lot of wildlife, including mountain lions,” Monroe said. “Based on the body of scientific research, they’re fairly hardwired. Those that have adapted to urban environments are not going to change very much.”
Many lions are secretive and territorial. Their longterm behavior will transcend anything that happens this summer, she said.
“The key driver is human population growth and habitat modification, especially to wildlife corridors and loss of connectivity,” Monroe said. “With wildlife and people, there’s a transformation of the conflict landscape across the state.”
Tom Stienstra is The Chronicle’s outdoor writer. Email: tstienstra@sfchronicle.com Twitter: @StienstraTom