Revisiting Old Friends: Eastern Chipmunk (Tamias striatus)

Eastern chipmunk at burrow entrance
Photo by Brad Sylvester, copyright 2012

For me, one of the best things about learning what lives in my yard, is that I can easily recognize things I couldn't identify before. Another benefit of this effort is that over time I can see the same creatures in different places, seasons and situations and really get to know them in more depth.

This morning, I was sitting on a small footbridge that I built over a stream that leads into the forest in my backyard photographing a new insect for this blog. As I pulled my eye away from the viewfinder after taking some macro shots, I noticed that I was under observation.

Eastern chipmunk (Tamias striatus)
Photo by Brad Sylvester, copyright 2012

A small brown furry head was peaking up from between some rocks about four feet away from me. Of course, anyone in New England can readily identify a chipmunk. Some may know that it is actually called the Eastern chipmunk or that its Latin species name is Tamias striatus. I didn't learn this particular species, or much new information about them when I initially described the Eastern chipmunk in this blog last July.

Those who read that post may remember that the chipmunk lives in underground burrows that measure from 5-10 feet in length with one or more living and storage chambers. Knowing this, when I saw the chipmunk watching me from between two rocks near a stream, I suspected that it was sitting right in one of the entrances to its burrow.

The small hole in the center of the picture
is the entrance to a chipmunk burrow.
Photo by Brad Sylvester, copyright 2012.

After snapping a few pictures of the chipmunk, I saw it turn and disappear into the cleft between the rocks where it had been sitting. As I suspected, this was the front door of its underground home. So I'm able to add a few extra pictures of the Eastern chipmunk and one of its den.

Quick facts about the Eastern chipmunk (Tamias striatus):

Lifespan: Eastern chipmunks live 2-3 years on average in the wild according to National Geographic.

When is it here? Eastern chipmunks live in New Hampshire all year round, but will remain below ground in their burrows during the cold winter months.

Nature's Hoarders

The Eastern chipmunk is a hoarder. It collects food all summer long, carrying it back to its burrow in preparation for the winter. The chipmunk does greatly reduce its activity level during the cold months, but doesn't go into a full hibernation. The food stored in its burrow sustains the chipmunk through the winter.

Tree Climbing

Although the chipmunk lives underground and generally forages on the forest floor, it is a quick and agile climber and will quickly scamper up a tree and sound a warning if threatened while away from its den.

Hand Feeding Chipmunks

Chipmunks are readily acclimated to humans by food offerings, and will take peanuts or similar food from the hand if food is given and gradually moved closer and closer to human presence. This is not recommended because it can lead to reliance on human feeding and selection of foods that have improper nutrition and resistance to spoilage to keep the chipmunk alive through the winter. It can also lead to chipmunks becoming a nuisance as they learn to associate people with food. Not to mention the fact that they can and will bite if startled or threatened and can carry serious diseases.

Candid Camera: Using a trailcam to identify animals

Trailcam poised and ready to strike
Photo by Brad Sylvester, copyright 2011. Do not copy.

Last year, I spent about six weeks doing some volunteer work for a local conservation agency. As a thank you gift, they gave me a gift certificate to the Kittery Trading Post, an outdoor sports and recreation specialty store in Kittery, Maine. With the certificate, I bought a trailcam. A trailcam, for those who have never heard the term, is a camera designed to be left outdoors along a suspected game trail to photograph animals as they pass by. It uses a built-in motion detector to determine when animals pass by. Once the motion detector is triggered it snaps a photo. This particular model works in both daylight and in complete darkness as it has an infrared flash that enables night-vision photos.

The trailcam is an ideal tool to help me capture photos of the animals that live in my yard. It can be set up by a bird feeder to snap pictures of every bird that visits during the day, or it can be used to catch nocturnal or crepuscular creatures that live in my yard that I might never see myself. Today, though, I have set it up to try to catch a shy diurnal mammal that I know lives in my yard.

Stripped pine cones and loose scales mean that something
was eating pine seeds here.
Photo by Brad Sylvester, copyright 2011. Do not copy.

To determine where to place the camera, I look for clues like the one in the photo to the right. There are several pine cones here on the ground that have been stripped as some animal pulled them apart to get at the tasty pine seeds nestled inside the cone. I found a number of these pine cones around the base of a big tree, with many of the cones and associated debris on a large flat rock next to the tree. The rock makes a great lookout point from which a hungry, but wary little animal might work at the pine cone while watching all around for any threats. At other times it might take the pine cone up into the tree to eat in an even more secure location leaving pine cone scraps all around the base of its favorite tree.

I strongly suspect that this is the work of a squirrel. A chipmunk would also eat pine cones like this, but would most likely eat on the ground and not climb a tree for that purpose. Although it is not above using a tree to escape a predator, chipmunks are ground creatures. Their nests are burrows. Squirrels (with some exceptions), on the other hand, are more arboreal, which means they live in trees. They build nests in the high branches of a tree or a cavity in the trunk and raise their young there. They are more comfortable in a tree than on the ground and are more likely to take their food up into the canopy both to eat immediately and for winter storage.




Trailcam aimed at the base of a large pine tree in my
 front yard where the scraps of pine cones were
found in abundance.
Photo by Brad Sylvester, copyright 2011. Do not copy.

  Rather than placing a trail cam at any random location and hoping to catch something, finding clues that some animal frequents the spot first helps improve the odds of getting the picture you want. In this case, I set up the camera to aim at the base of the tree, on the side where the flat rock lies. The one thing I don't like about the camera is that there is a delay of a several seconds between the time when the motion detector is triggered and when the picture is taken. This is fine to allow larger, slow moving animals like deer to fully enter the camera's field of vision before it takes a picture, but for small, fast moving animals like squirrels, it can mean that they trigger the motion detector and are long gone before the picture is taken. We'll see how it works.

I'll post an update when I have some pictures to show of whichever animal has been eating the pine seeds. In New Hampshire, where I live, there are four species of "conventional" squirrels: the grey squirrel, the red squirrel, the northern flying squirrel and the southern flying squirrel. I say conventional squirrels because the woodchuck is actually a kind of squirrel as well, as is the chipmunk. I suspect the culprit in this case is either an eastern grey squirrel or a red squirrel.

Eastern Chipmunk

Eastern Chipmunk (Tamias Striatus) July 5, 2011
Photo by Brad Sylvester, copyright 2011, all rights reserved

I can tell that for the first weeks of this blog, at least, it’s going to be very easy to find new species of animals to add to the list of what lives in my yard. Even as I snapped the photos of the Two-striped Grasshopper yesterday, I heard a familiar short, sharp “tseet!” repeated every few seconds from the canopy of a maple tree that stands beside my back deck. I knew I had my second entry if I could just spot the Eastern chipmunk (Tamias striatus) that was calling from some hidden spot within the branches.

Fortunately, high-pitched sounds are easier for the human ear to locate. After a few more calls, I had it pretty well narrowed down, and then a small movement caught my eye. Sure enough, a chipmunk was peeking down from above, watching me intently for any sign of a threat.

Chipmunks, of course, are familiar to almost everyone in New England. If you have trees in New England, you probably have chipmunks nearby even though they actually live in burrows in the ground. Chipmunks store food in their burrows during the months of plenty against the colder months when food will be scarce (or frozen solid).

In my yard, they have a plentiful supply of acorns. The cracked and empty acorn shells attest to their appetite for these nuts. They also have a bad habit of eating my strawberries, just as they begin to ripen. Chipmunks are also known to eat insects, worms, grains (including commercial chicken food when the chickens aren’t looking).  They will chew food into manageable pieces and then stuff their cheek pouches full to carry it back to special food storage chambers within their burrows.

Like many animals, though, chipmunks are opportunistic and will eat a wide variety of foods if the occasion presents itself. Bird eggs, unprotected small baby animals, fungus, and some types of kitchen waste may also become part of the chipmunk’s diet.

In turn, says the State of Connecticut’s Department of Environmental Protection, chipmunks are eaten by hawks, owls, bobcats, weasels, foxes, house cats, raccoons, snakes, rats and coyotes. I would also add fisher cats as a common predator of the chipmunk in areas (like New Hampshire) where they co-exist.

If you need to remove a pest chipmunk, smearing a bit of peanut butter on the trigger of a live trap works quite well as they can’t remove it in one grab and eat it elsewhere, but they have to keep working the trigger to get every last bit. Eventually, if not right away, they’ll trip it and be trapped.

Chipmunk burrows are generally well-hidden and usually have more than one entrance. They may extend for 5-10 feet in length with several chambers. The Eastern chipmunk may have one or two litters of 3-5 babies each year says New Hampshire Public Television’s chipmunk info. page.

Although chipmunks are not seen above ground in winter unless their dens are seriously disturbed, they don’t hibernate in the true sense. They do stay inside their burrows though, living off the food they have stored from the previous summer and sleeping. Occasionally, they will make their burrows in the walls or foundations of homes if they can find a way in, although more frequently if you hear something in the walls or ceiling of your home, it will be a squirrel, which unlike the chipmunk, nests above ground.