Flying Squirrels: North vs. South

Flying Squirrels: North vs. South

Illustration by Adelaide Tyrol

The calls come in all winter, said Paul DeBow of DeBow Wildlife Service in Plymouth, New Hampshire. If there is no snow, the peak will be in January or February, when it’s the coldest. Some people think the animals they hear partying in the attic are chipmunks, he says. Chipmunks in the attic in the middle of winter. But they are not.

Chipmunks, DeBow explained, hibernate in winter and what homeowners are probably hearing are flying squirrels. Because flying squirrels are nocturnal, few people ever see them.

There are two species of flying squirrels in our area, the northern flying squirrel and the southern flying squirrel. John Litvaitis, professor of wildlife ecology at the University of New Hampshire, said that the southern flying squirrel is the smaller of the two, often weighing just two or three ounces. “The northern flying squirrel [at three to five ounces] may be half again or may be twice as big as the southern,” he said.

But even the northern flying squirrel is smaller than a red squirrel. The southern flying squirrel is about the size of, yes, a chipmunk (which is a ground squirrel). Both species of flying squirrels can be distinguished from other squirrels by their patagium, the membrane between their front and rear legs that allows them to glide (not fly).

For all their similarities, the northern and southern flying squirrels are in a conflict that sounds a lot like war. “There was one paper that was titled something like, ‘The South Advances, While the North Retreats,” said Carolyn G. Mahan, professor of biology and environmental studies at Pennsylvania State University, Altoona, and a squirrel researcher.

Northern flying squirrels are creatures of conifer (cone-bearing tree) forests. “We know that northern flying squirrels depend on fungi that are associated with conifer forests,” she said. But southern flying squirrels can live anywhere. When conifers are cleared from a mountainside and homes are built, southern flying squirrels are happy to move in, bringing several more threats to the northerns. It’s not that the two species don’t get along; it’s that they get along too well. Squirrels of both species will pile into the same tree cavity on a cold winter night. Hybrids between the northerns and southerns follow.

The southern flying squirrels carry an intestinal parasite, unknown in northern squirrels in places where there are no southern flying squirrels. Where the two species overlap, the parasite may be harming the northerns directly, or, as Mahan’s research shows, the parasite may be altering the northern squirrel’s internal ecosystem, allowing other, previously harmless parasites to join forces with the newly introduced parasite.

The northern flying squirrel is in serious decline in the higher elevation forests of Pennsylvania, Virginia, West Virginia, and North Carolina. It is a state-endangered species in Pennsylvania. The Carolina flying squirrel, a subspecies, is federally endangered.

As the many phone calls to DeBow Wildlife Services suggest, northern and southern flying squirrels seem to be doing just fine in New Hampshire and Vermont, although it would be hard to tell if the southerners were overtaking the northerners as they are in other places. That mystery is the only reason both northern and southern flying squirrels are “species of greatest conservation need” in Vermont’s 2005 Wildlife Action Plan.

Litvaitis did studies of flying squirrel habitat in the 1990s in New Hampshire. Southern flying squirrels are dominant along the seacoast and the southern 20 percent of the state, he said – basically anywhere you find acorns and hickory nuts. “As you get inland and northern, it flips to northerns,” he said. He assumes the pattern is similar in Vermont.

One of the more recent studies on flying squirrels done by Litvaitis’ students focused on the animal’s energy use. That patagium, or gliding membrane, exposes a lot of a flying squirrel to the elements. “Once the temperature got below freezing, they buddy up,” he said, for warmth. “There are real benefits.”

That buddying up can mean up to 50 flying squirrels in your attic during the winter, explained DeBow. “You can’t trap them out,” he said. “It’s like bailing a leaky boat.” Instead, he uses exclusion, using either a one-way door or a cone that discourages them from re-entering.

These are the same tools DeBow uses for bats, but when it comes to control, he likes flying squirrels better for a few reasons. One is because, unlike the region’s disease-decimated bats, flying squirrels seem to be thriving, at least in the region’s attics. He thinks the popularity of improperly screened ridge vents may be one reason.

The other reason is that they are so boisterous and noisy. DeBow never has to guess when he’s gotten the last flying squirrel to leave the party.

Madeline Bodin is a writer living in Andover, Vermont.

  1. Ron
    Jan 25, 2013

    We had a terrible time getting rid of a nest of flying squirrels in the ceiling and they made bad urine stains. I finally took the ceiling down nest and all. There was a mother and four young ones that I could see. I gathered them up and took them down the road about a half mile. When I finished sweeping up I found a fifth young one which I left there for the night. In the morning it was gone. All the young ones were new born and could not go anywhere by themselves so I must assume that the mother returned.

  2. M & R Pascucci
    Jan 27, 2013

    What a wonderful article. 
    So much useful information. Glad to pass it along to other interested parties.

  3. Bob Weltzien
    Jan 13, 2018

    I have them in the walls above the garage and it’s obvious how they got in. I don’t want to kill them with snap traps but if I am able to relocate them with live traps wouldn’t they succumb to the elements? We are having the worst winter in 25 years.

  4. Kathy Langlois
    Jan 25, 2018

    Bring the flying squirrels you trap to the wildlife rehabber. They will take them from you and care for them until they can safely release them. Every state has wildlife rehabbers through Fish and Game.

  5. Scott
    Mar 06, 2018

    Kathy said “Bring the flying squirrels you trap to the wildlife rehabber. They will take them from you and care for them until they can safely release them. Every state has wildlife rehabbers through Fish and Game.” 

    Not always so easy. I rehabilitated ONE female which my cat brought in as a tiny baby and I still have it in my care 6 months later. Every single ‘rehab’ place refused it saying they were at capacity which was utter nonsense because I know they operate on government grants here in Ontario and they were just being picky and lazy…while at the same time bragging to me that they do take in Flying Squirrels. What’s the point of a rehabilitation center that refuses animals? This is Ontario Canada for you.

  6. Donna Arizmendi
    Apr 13, 2018

    For the very first time I have a flying squirrel living in one of my tress.  It is so cute. It comes down at night to eat out of my bird feeder.  They are not considered rodents according to our fish and wildlife biologist.  They are very similar to a sugar glider.  I quess I’m lucky to live in the country where I can appreciate all wildlife.

  7. Daniel Roeder
    May 29, 2018

    My family is caring for one after the rehab center said they were full (much like Scott said) and they are the fastest and most adorable things ever. We also got a tin of walnuts, pecans, hazelnuts, and almonds and he hid them all in one night (some even ended up in my bag for school).

  8. Kathleen Davidson
    Oct 20, 2018

    While vacationing in the white mountains recently, I came across the friendliest flying squirrel ever. It was so adorable that I wanted to bend down and pick it up, but I thought better of it because it could have had rabies.I don’t think it did but you never know. As I stood still watching him he came up to me and walked over my boots then he sat next to my boot for about 2 minutes or more. Just then I remembered that I had some trail mix in my pocket. I put some trail mix on a rock nearby which he scampered over to and ate it all in a flash. I think he stored some in his cheeks for later. I named him Rocky the flying squirrel then I said goodbye and bid him farewell. It was the best encounter ever!!!!!

  9. David Crockett
    Nov 05, 2018

    In the late fall of 2017, on a cold night, I went into one of my sheds and saw something run out of the eve. I stood there and as it started to come back in,  it looked like a mouse to me. Then it stepped in and I saw it was a small squirrel. Then two more came in. I was only about four or five feet away.
    They didn’t seem very scared of me. So I went to get some sunflower seeds. I went in the shed, and they just stood there. I put some seed on the shelf. They came right down and started to eat them. I put some seeds in my hand one jumped in my hand and just sat there eating. The next night I went in again,  sure enough they were there.  I hand feed them again. Then later in the winter, they seemed to multiply. At one point I had thirteen (that I could count in sight) eating out of my hand. I kept feeding them every night all winter long.

    Then about April 2018 some of them seemed to disappear. Only two or three hung around.  I kept feeding them every day. Most of the summer of 2018 I had some of them every night.  Then as of November 2018 as the temperature keeps dropping more are showing up. The last two weeks as I walked up to feed them,  they would fly from tree to tree following me to the shed. All I had to do was to call them and whistle.

    Tonight Nov 5th as I went to feed them, it is about thirty nine degrees out. I got almost to the shed, and four flew onto a tree right next to me. They went to the shed and we’re waiting for me when I went in.

    I would like to know what else I can feed them other than sunflower seeds. 


  10. Peter Biddle
    Nov 29, 2018

    We have had flying squirrels in our attic probably for the last 2 years.  We would even hear them in the walls of the 2nd floor. If I knocked on the wall while they were asleep during the day they would make a scurrying sound then calm down again. When I went up to see how they were getting in, it was pretty obvious as there was a hole in the thin roof vent screen at the end of the gable.  These guys weren’t scared of me at all.. I would go to the attic to see what i could see, turn on the lights, and one would just come scurrying up from the insulation in the wall and just stare at me.  I started putting some dry dog food nuggets on the plywood floor to see if they would take them, which they did.
    Eventually, the scurrying sounds in the walls started being heard on the 1st floor, and in the eves of our overhanging porch.  This was simply too much for my wife, so it was time to try to get rid of them.  I put up a Wifi camera so I could observe their habits going in and out of the hole. At the time I thought I only had 4.  I saw 2 go out of the hole, so I went up and sealed the hole, then put down a humane trap to get the other 2.  It took less than 10 minutes to catch the first one, he was really cute, didn’t seem too alarmed, he even sat there eating the rest of the peanut butter after the trap door snapped closed!  These guys are very chill!  I released it in my back yard, where I think they also are living in a hollowed out stump, at least that’s where he ran to immediately.  I went through the same routine with the second one, then noticed in my video feed 2 more crawling around.
    Needless to say, it is now 3 days later and I have caught a total of 20 so far and released them outside.  I’m pretty sure they aren’t getting back in, I added a much stronger screen, and things are sounding much calmer at night, so their numbers MUST be decreasing, right?  It is late November and I hope they survive by finding another home in that stump or some other natural protection.  They are the cutest things, I started releasing them from the trap at a height of 5 feet and watch them glide to safety each time.
    Collegeville, PA

  11. Robin
    Dec 04, 2018

    I read that flying squirrels can transmit Typhus…is this true?

  12. Tom Sutkins
    Dec 23, 2018

    I saw our first flying squirrel in the winter of 1994 and watched as he glided across the yard from the maple tree just behind our rural home.

    That was 24 years ago and had not seen one since until a few nights ago. As I walked onto our deck about 6 pm a beautiful sight caught my eye, three flying squirrels were together on the side of the same maple tree peering down at me only 10 feet away. This time I had to show my wife her first flying squirrel. She too was delighted as they appeared calm and in no hurry to glide off. It looked as though they were after the sunflower seeds that filled the bird feeders only a few feet away. I hope to see them again some night in the near future. I have cell phone photos of one them that I can post.

  13. Rick
    Jan 04, 2019

    Pest Control company just left the house as we have a bat problem. He also located a Flying Squirrel entry. They are cute right up to the point where they invade the house. Looking at some big money to resolve these two issues so, cute? Nope, not so much.

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