Flying Squirrels in Your Backyard?
Cherise Skeba
If your home is near water and tree groves including trees with cavities, you may have flying squirrels in your yard and not know the squirrels are there. Flying squirrels are nocturnal animals that come out to eat for a few hours after sunset and sometimes in the early morning hours prior to sunrise. Read on to learn more about these wilderness residents and backyard visitors.
There are two species of flying squirrels in Minnesota: southern (Glaucomys Volans) and northern (Glaucomys Sabrinus). Southern flying squirrels live in deciduous trees in Southern Minnesota and northern flying squirrels live in conifer or deciduous forests in Northern Minnesota but there is an overlapping zone that extends from Bemidji to Duluth. Southern flying squirrels can also be found in all states along the length of the Mississippi River and states east of the Mississippi River. Northern flying squirrels are more prevalent in Canada but can be found in Northern Minnesota and other northern areas stretching east through Maine. If you see a flying squirrel in Dakota county, the squirrel is a Southern flying squirrel.
Flying squirrels are in the same mammal family (called Sciuridae) as other squirrels and chipmunks. Flying squirrels have gray, brown, reddish brown or tan fur on their backs with white or cream-colored bellies. Northern flying squirrels may have mottled color on their bellies. Both species have large eyes with open pupils that almost fill the entire eye, making the eye look nearly black and giving the squirrels good night vision.
The southern flying squirrel is about the same size as a chipmunk and is slightly smaller than the northern flying squirrel. Researchers are challenged to identify the southern versus northern flying squirrels when viewed in the wild but can distinguish the species using special equipment that picks up the ultrasonic sounds of the flying squirrels. Like bats, flying squirrels make many sounds that are too high pitched to be heard by human ears. However, flying squirrels also make chirping and squeaking noises similar to bird noises.
Flying squirrels do not fly but instead glide by stretching out a membrane (called the Patagium) connected to their wrists and ankles. The squirrels have cartilage coming out of their wrists that allows them to stretch open the membrane, giving them stability in air. The squirrels also flatten their tails and use their tails as rudders to steer, balance and brake while in flight. A flying squirrel lands by curling up its tail to slow down and pointing its hands and feet forward to grasp the target spot. Southern and northern flying squirrels often glide 20 to 30 feet but can glide up to 150 feet and can even turn up to 180 degrees while in flight.
Southern and northern flying squirrels eat fungi, insects, berries, tree sap, lichen and nuts. The squirrels will stock food for winter since they do not migrate. However, they spend less time out foraging for food during winter and will huddle together and lower their body temperature to save energy on very cold days. Flying squirrels nest in tree cavities, squirrel leaf nests, nest boxes and sometimes on the ground. In fact, flying squirrels have been found sharing a nest with ground squirrels.
Flying squirrels mate in early spring and give birth to 3 to 5 babies 40 days later. The mothers nest separately when they have babies since the females do not want others around when they have young. It is not known exactly how long mothers nurse and care for their babies but babies normally try their first flight about 5 weeks after birth. You can witness the first flight of a baby flying squirrel in the following YouTube video captured by BBC Earth.
Owls are the most common predator of flying squirrels since both animals are nocturnal. Flying squirrels may also be hunted by foxes, fishers, martens, feral cats, coyotes and raptors. You can provide safe housing for flying squirrels by adding nest boxes to your yard (sample box designs 13, 14). However, flying squirrels will probably not use the nest boxes unless the nearby habitat is already conducive to flying squirrels.
Fun fact: flying squirrels glow pink under ultraviolet light.
References:
“Flying Squirrels in a Changing World”, Michael Joyce, Natural Resources Research Institute, University of Minnesota of Duluth and Minnesota Department of Natural Resources, http://www.youtube.com/watch?v=4IWhmhn9GdU
“Flying squirrels”, Minnesota Department of Natural Resources, http://www.dnr.state.mn.us/mammals/flyingsquirrel.html
“Southern flying squirrels are climate migrants”, Natural Resources Research Institute, University of Minnesota, http://nrri.umn.edu/news/flying-squirrels
“Flying Squirrels, Our Hidden Neighbors”, Friends of the Wildflower Garden, http://friendsofeloisebutler.org/pages/gentian/newarticles/flyingsquirrels.html
“Southern Flying Squirrel”, Illinois Department of Natural Resources, http://dnr.illinois.gov/education/wildaboutpages/wildaboutwildmammals/wildaboutmammalsrodents/wawmsouthernflyingsquirrel.html
“Flying Squirrel”, Wisconsin Department of Natural Resources, http://dnr.wisconsin.gov/topic/WildlifeHabitat/orphan/Flying_Squirrel
“Woodland Wildlife Spotlight: Southern Flying Squirrel”, University of Maryland Extension,
http://extension.umd.edu/resource/woodland-wildlife-spotlight-southern-flying-squirrel/
“Southern Flying Squirrel”, University of Michigan, BioKids, http://www.biokids.umich.edu/critters/Glaucomys_volans/
“Southern Flying Squirrel”, Maryland Department of Natural Resources, Wildlife & Heritage Service, http://dnr.maryland.gov/wildlife/Pages/plants_wildlife/Southern_FlyingSquirrel.aspx
“Protected Species in Pennsylvania: Northern Flying Squirrel” PennState Extension, http://extension.psu.edu/protected-species-in-pennsylvania-northern-flying-squirrel
“Northern Flying Squirrel”, Minnesota Seasons, http://www.minnesotaseasons.com/Mammals/northern_flying_squirrel.html
“Flying Squirrel Frequently Asked Questions”, Wisconsin Department of Natural Resources,
http://widnr.widen.net/s/lqdg6tbbzb/flying-squirrel-faq_final
“Instructions on where and how to place nest boxes for southern flying squirrels”,
“Southern Flying Squirrel Project - Nesting Boxes”, School of Natural Resources, University of Nebraska, http://snr.unl.edu/research/projects/flyingsquirrel/sfs-nestingbox.aspx