To survive this week’s historic heat wave, much of the Bay Area’s wildlife finds relief in deep burrows, wet mud or dense brush.
But baby tree squirrels, unable to dig or climb, are falling from tall trees, landing in a big mess.
Calling it “squirrel-palooza,” Bay Area wildlife rescue groups are reporting a rush of distressed animals and are mobilizing teams to rescue the rodents with ice packs, fluids, medications and special diets.
“They are literally jumping out of their nests to escape the heat,” said Buffy Martin Tarbox of the Peninsula Humane Society, which is treating 101 squirrels. Dehydrated and sometimes injured, the youngsters “don’t have the climbing skills to get back up.”
The Silicon Valley Wildlife Center is caring for 188 tree squirrels and more are expected, Executive Director Laura Hawkins said. Of them, 138 are swaddled in small cages that are stacked on shelves, and 50 are cared for in volunteer homes. At one point, 14 squirrels arrived in an hour.
“Everyone here is feeding the squirrels,” Hawkins said. To ease the workload, the center is calling on additional volunteers to rotate four-hour shifts.
At WildCare of San Rafael, which is also experiencing an increase in demand, “every little one we’ve admitted this week has come in with symptoms of hyperthermia,” said Alison Hermance, director of communications. San Francisco’s Yggdrasil Urban Wildlife Rescue typically receives one to three baby squirrels per week; now, he’s getting four to seven every day.
Animals with heat-related problems need immediate attention and constant monitoring, Hermance said.
“As with humans, wildlife patients need to cool down, but you can’t cool them down too quickly or you risk brain and other organ damage and death,” he said. Seizures are another risk, she added.
Baby squirrels are so small that they cannot receive the usual emergency intravenous fluids. Instead, they must be rehydrated with fluids injected under the skin at the nape of the neck. Each one is fed with a syringe filled with a special formula. To tell siblings apart, they can wear a colorful dab of nail polish on one ear.
Other animals are also feeling the heat, with centers reporting an increase in felines in need, skunks, opossums, fawns, some songbirds and cavity-nesting birds such as woodpeckers.
“We’ve definitely seen an increase in bobcats,” said Ashley Quick, executive director of the Morgan Hill Wildlife Rehabilitation and Education Center. The center usually treats one or two, but is now treating four, including a young man found by hikers on a trail in Carmel.
On Wednesday, Walnut Creek’s Lindsay Wildlife Experience received a golden eagle that was severely dehydrated.
Heat affects wildlife in different ways, depending on a species’ exposure, physiology and behavior, said Jonathon Stillman, a professor of biology at San Francisco State University and an adjunct professor of integrative biology at UC Berkeley.
Reptiles, which are adapted to heat, are not stressed by our heat wave. They need much less water than mammals, birds, amphibians, fish or aquatic animals, Stillman said.
Fish are greatly affected by heat spikes, if the water is no longer cool and oxygenated. If possible, they will look for deeper pools to ride out a crisis, said Joe Sullivan, Fisheries Program Manager at the East Bay Regional Park District.
Mammals such as dogs, bears, and adult squirrels “splash,” that is, flatten themselves on cool ground to reduce body heat. And mammals may sweat or pant to cool down, Stillman said. “But if we’re dehydrated, we can’t do that,” he said.
When it’s hot and thirsty, wildlife will roam much further in search of a drink: to our yards to drink from birdbaths or rummage through irrigated gardens. Deer are more likely to venture to roadsides to eat moist plants in roadside ditches, risking a collision with a car. Their carcasses attract scavengers, who are also in danger.
Baby squirrels, without a source of water in their nests, dehydrate easily. Their nests heat up quickly because they are packed with siblings and insulated with leaves, bark, palm fronds and other materials, said Ashley Kinney, hospital manager for the Silicon Valley Wildlife Center.
Restless and restless, “sometimes they move to find a cooler spot and unfortunately fall out of the nest,” he said.
If our heat wave had come earlier in the season, resorts say they would have been inundated with an influx of baby birds, not squirrels. Last year’s extreme heat in the Northwest in late July inundated wildlife rescuers with young raptors that had jumped from their nests to try to escape deadly temperatures.
Of the stressed squirrels, very few are native Californians. Almost all are eastern gray squirrels, released here in the 20th century from the wetter, cooler East Coast. Abundant in our parks and yards, the species is prolific, producing two litters a year, but a late-summer heat wave can put that second litter in jeopardy.
Our native western gray squirrel does best in a late summer heat wave. She only has one litter, in the spring, and now all her pups have left home.
There is growing evidence that heat waves can benefit other native species.
While invasive bullfrogs need water throughout the year, our native frogs can simply find small deep burrows and aestivate, a form of hibernation during the summer. Dry, warm periods could limit the spread of the invasive Argentine ant, because it needs moisture, Bay Area entomologist Merav Vonshak said.
“Life is risky,” said Stuart Weiss, chief scientist at the Creekside Center for Earth Observations in Menlo Park. “And we just shot ‘snake eyes.’ It had never been so hot before.”
“Each species is just doing their thing, and then you have an event like this,” he said. “Some will be in the wrong place at the wrong time.”
Find a wildlife rescue and rehabilitation center near you:
If you find a baby squirrel:
- Call a wildlife rescue center and ask for advice.
- If you pick it up, use a towel or cloth.
- Make it comfortable in a cool, dark, well-ventilated box.
- Do not give him food or water. Icy water can cause shock. Food can cause aspiration injuries.