Tuesday, I received an email from fellow nature-lover Jim Tucker, informing me that his backyard gray squirrel population had gone from nearly a dozen to zero in less than a week. Furthermore, Jim said he hadn’t seen a single squirrel in his Red Bank neighborhood or in the woods behind his house. He asked if I had noticed a similar decline in squirrels here at the Chattanooga Arboretum and Nature Center. I told him that I really hadn’t noticed, but that I would definitely pay closer attention.
So for the past three days I have been on alert, watching for the furry rodents and listening for their chatter here and also while taking my daily walk. As of today, I’ve seen a total of exactly one. This is very strange. Are the squirrels moving to higher ground to seek relief from the unusually high temperatures, and come fall, they will return to their home territories? Are we witnessing a microcosmic example of what is already occurring on a global scale? Or are there other, more mundane explanations for this?
I explored the idea that our squirrel population may be affected by climate. According to Discovery News (Aug. 18, 2011), researchers have compiled past studies on species migration and combined them into a meta-analysis that showed a clear trend toward cooler climates, with the fastest moves in places where heating was most intense.
“These changes are equivalent to animals and plants shifting away from the equator at around 20 centimeters per hour, for every hour of the day, for every day of the year,” said project leader Chris Thomas, biology professor at the University of York.
One small example of species migration is the dragonfly in Great Britain. They are moving northward, according to U.K. Natural History Museum scientist Steve Brooks. Dragonflies love warm temperatures, and so the ones that live in the U.K. have mostly been confined to the south of the country, until recently. Since 1980, 34 of 37 British species of dragonfly have expanded their range northwards by an average of 74 kilometers. According to Brooks, this is evidence that the U.K.’s climate is growing warmer.
Back to our gray squirrels-suppose they disappeared from our area forever, that they moved up north to Minnesota or Maine or Canada? How would their disappearance impact our local ecosystem in Chattanooga? I can hear some saying, “Good riddance. We’re better off without those unwelcome birdfeeder raiders and attic tenants.” But squirrels moving away could create some serious consequences. It’s all about the food chain and the interdependence of nature.
The gray squirrel is an important prey species for a whole host of predators, including hawks, owls, snakes and foxes. If one or all of these predators moved away to follow the squirrels, other species not native to the area could move in to take their niche. This happened several decades ago when the red wolf, the top predator in the Southeast, was replaced by the urban-dwelling coyote.
Besides providing food for other creatures, squirrels are beneficial to the ecosystem for another reason. They are nature’s tree planters. Wilkes University biology professors Michael Steele and Peter Smallwood are researching the nutty truth on squirrels and acorns. Tree squirrels are one of the most important animals for helping oaks spread because they store acorns in the ground, practically planting baby oak trees, according to Smallwood. The researchers note that evidence is accumulating that-along with blue jays and a few other small animals-squirrels are important in maintaining and regenerating second-growth oak forests and may even have been responsible for spreading the vast stands of oak throughout North America.
Other explanations for a temporary decrease in the squirrel population are related to food and breeding. Summer is often the most difficult time for finding food, and it could be even more so when there are temperature extremes. Also, squirrels have two litters a year, one in the spring and the second coming in August or September. Before the summer babies are born, the mother chases off the previous young and becomes very secretive just before the birth. I’m guessing that one of these explanations is probably the cause of our missing squirrels.
But the unusually quiet forest at the Chattanooga Arboretum and Nature Center these past few days has given me pause. I’ve missed the little critters. So whether the gray squirrels are just taking a short vacation in cooler climes, beginning a mass northern migration, or their search for food has taken them to other locations, their absence at this moment reminds me again how precious every species is to this planet. Each is uniquely important and needs to be understood and protected. I am more convinced than ever of our need to befriend life in all of its spectacular forms, every single day.
Jean Lomino, executive director
Chattanooga Arboretum and Nature Center
The opinions expressed in this letter to the editor belong solely to the author, not Nooga.com or its employees.