In a heat wave, young, hot squirrels are falling from the trees

To survive this week’s historic heat wave, much of the Bay Area’s wildlife finds comfort in deep burrows, wet mud or thick bushes.

But the little tree squirrel, unable to dig or climb, falls from tall trees – descends into a great mess.

Wildlife rescue groups in the Bay Area, dubbed the “squirrel balooza,” have reported a wave of distressed animals and are mobilizing teams to rescue the rodents using ice packs, fluids, medication and special diets.

“They literally jump out of their nests to escape the heat,” said Buffy Martin Tarbucks of the Peninsula Humane Society, which treats 101 squirrels. Due to dehydration and occasional injury, the youngsters “do not have the climbing skills to stand up again.”

Executive Director Laura Hawkins said the Silicon Valley Wildlife Center is caring for 188 squirrels, with more expected. Of these, 138 are placed in small cages stacked on shelves, and 50 are being cared for in volunteer homes. At one point, 14 squirrels arrived in an hour.

“Everyone here serves squirrel feed,” Hawkins said. To ease the workload, the center invites additional volunteers to rotate during four-hour work shifts.

“All of the youngsters we admitted this week have shown symptoms of hyperthermia,” said Alison Hermans, director of communications, at San Rafael’s WildCare, which is also seeing increased demand. Yggdrasil Urban Wildlife Rescue in San Francisco typically receives one to three young squirrels per week; Now, the number is increasing from four to seven every day.

Animals with heat-related problems need immediate care and constant monitoring, Hermanns said.

“As with humans, wildlife patients need cooling – but you can’t cool them down too quickly or you risk damage to the brain and other organs and death,” she said. She added that seizures are another danger.

Baby squirrels are too small to get their usual emergency IV fluids. Instead, they should be moistened with fluids injected under the skin at the back of the neck. Each one is fed with a syringe filled with a special formula. To distinguish the siblings from each other, they may wear a colorful touch of nail polish on the ear.

Other animals are also feeling the heat, with centers reporting an increased need for felines, skunks, opossums, cows, some songbirds and cavity-dwelling birds such as woodpeckers.

“We’ve definitely seen an uptick in bobcat numbers,” said Ashley Quick, executive director of the Morgan Hill Wildlife Education and Rehabilitation Center. The center usually sees one or two but is now treating four, including a young man found by hikers on a trail in Carmel.

On Wednesday, the Lindsay Wildlife Experience from Walnut Creek received a golden eagle that was severely dehydrated.

Heat affects wildlife in different ways, depending on species exposure, physiology and behavior, said Jonathon Stillman, professor of biology at San Jose State University and assistant professor of integrative biology at UC Berkeley.

Reptiles, which are adapted to heat, are not stressed by our heat wave. Stillman said they require much less water than mammals, birds, amphibians, fish or aquatic animals.

Fish are highly affected by thermal surges, if the water is no longer cold and oxygenated. If possible, they will look for deeper ponds to weather the crisis, said Joe Sullivan, director of the East Bay Regional Park District’s fisheries program.

Mammals such as dogs, bears, and adult squirrels do “wasteers” – flattening themselves on cold ground to reduce body heat. Mammals can sweat or pant to cool off, Stillman said. “But if we’re dehydrated, we can’t do that,” he said.

When you’re hot and thirsty, wildlife often roams around for a drink—in our yards drinking from birdbaths or digging through irrigated gardens. Deer are more likely to venture out onto road edges to eat wet vegetation in roadside ditches, putting them at risk of crashing into cars. Their corpses attract scavengers who are also in harm’s way.

Young squirrels, which do not have a source of water in their nests, dry out easily. Ashley Kinney, director of the Wildlife Center of Silicon Valley Hospital, said their nests warm quickly because they are crowded with siblings and insulated with tree leaves, bark, palm fronds and other materials.

Agitated and dulled, she said, “sometimes they will move to find somewhere cooler and, unfortunately, will fall out of the nest.”

If our heatwave had arrived earlier in the season, the centers say it would have been drowned out by an influx of young birds, not squirrels. Last year’s sweltering heat in the northwest in late July engulfed wildlife rescuers with young raptors that jumped from their nests in an attempt to escape the deadly temperatures.

Among the stressed squirrels, there are very few native Californians. They are almost all eastern gray squirrels, and they were released here in the 20th century from the wetter and colder east coast. Found in abundance in our gardens and yards, the species is lush, with two ventricles a year – but a heat wave in late summer can put a second litter at risk.

The native western gray squirrel does best in a late summer heat wave. She has only one litter, in the spring, and now all her offspring have left the house.

There is mounting evidence that heat waves may benefit other native species.

While invasive American frogs need water all year round, our domestic frogs can simply find small, deep burrows and breed – a form of summer hibernation. Bay area entomologist Merav Funchak said hot dry spells can limit the spread of invasive Argentine ants, as they need moisture.

“Life is suspicious,” said Stuart Weiss, chief scientist at the Creekside Earth Observation Center in Menlo Park. “And we just rotated the ‘Snake Eyes.’ It was never hot before.”

“Every kind does its thing,” he said, “and then you get an event like this.” “Some will be in the wrong place at the wrong time.”


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.
  • Keep it comfortable in a cool, dark and well-ventilated box
  • Do not give him food or water. Ice water can cause shock. Food can cause suction injury.

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