[Vertebrate Pests] Chipmunks and Real Estate Transactions

As we know, structural properties must be inspected and "cleared" during real estate transactions for issues relating to termites and other wood-destroying organisms. Part of the driving force for WDO disclosures during transactions is that termites are considered cryptobiotic animals; that is, they are secretive and elusive in their habits. Eventually, accumulating damage results in costly repairs, sometimes costing thousands of dollars.

OK, so where am I going with a discussion on termites in a vertebrate pests column addressing chipmunks? The chipmunk is a mammal, not an insect. Nor does it destroy or weaken wood.

But, the chipmunk also damages structures, in some cases at monetary and physical amounts that are greater than that of termites. But similar to the termite, the chip-munk’s damage to structures and structural elements is often insidious. Thus, I believe chipmunks, like termites, should be disclosed on real estate transactions.

THE CHIPMUNK. The chipmunk and its pest importance has become more relevant for a couple of reasons. First, in many established suburban neighborhoods in the Eastern half of the U.S., chipmunk populations are thriving and expanding. This is because the chipmunk is taking full advantage of the habits of many suburbanites who are transforming their own "nest sites" into peaceful refuges away from their stressful lives.

More suburbanites are into gardening and planting thick, lush, landscaping. They also are installing rock gardens, mini-walls, and rocky water pools and gardens. As trees in neighborhoods become older they form shady harborages, nuts for food and ideal nesting zones among tree root bases.

Moreover, many of these homeowners are also installing bird and squirrel feeders. Some homeowners enjoy not only attracting birds to the feeders, but many also delight in watching "Chip and Dale" chase each other around their yard as well as watching them "munch" on bird seeds or chipmunk food.

"Behind the scenes" it’s another matter. The chipmunk is a ground squirrel. As such, the chipmunk digs burrows and constructs its nest underground. Away from buildings in the wild, chipmunk burrows help maintain healthy soil environments. Around structures however, the soil displaced by chronic chipmunk infestations can result in significant damage to basement walls, cement patios, walkways, stairs, foundations, etc.

INSIDIOUS DAMAGE. A couple of chipmunks and their burrows are not likely to pose a significant threat. The problem becomes that typical of rodents, chipmunks multiply.

The Eastern chipmunk, for example, mates twice each year, during early spring and again during the summer or early fall. Two to five young are born in April to May and again in August to October. The young are sexually mature within one year. Providing that predators do not kill them, adults may live up to three years. A chipmunk’s home range may be up to ½ acre (0.2 ha), but the adult typically defends a territory about 50 feet (15.2 m) around the nest area.

In wildlife-friendly yard environments, it is not uncommon to have 15 or more chipmunks sharing the spaces around a home on a 1-acre lot. In one residential home in Indiana, I live-trapped 35 chipmunks over the course of only one year around the foundation and backyard perimeter.

BURROW SYSTEMS. A typical main tunnel of the chipmunk is 20 to 30 feet (6 m to 9 m) in length and about 2 inches in diameter. More lengthy and complex burrow systems can occur in some areas. Burrow systems normally include a nesting chamber, one or two food storage chambers, various side pockets connected to the main tunnel and separate escape tunnels.

Obviously, with a population of chipmunks, the amount of soil displaced away from a building can be quite significant. Ten chipmunks all excavating burrow systems of these lengths from below or next to structural items leads to support problems. Again, like termites, the first few years (and the first few chipmunks) are not likely to be the issue. The issue is in the long term; the slow accumulating loss of structure-supporting soil.

Also similar to termite damage, chipmunk damage often goes unnoticed for long periods until significant damage has occurred. This is because chipmunk burrows around buildings and structural elements are typically concealed near objects or buildings. Nor are mounds of dirt always visible to alarm a homeowner of a burrowing threat, because chipmunks often carry the dirt excavated from the burrow in their cheek pouches and scatter it away from the entryways.

REAL ESTATE DISCLOSURE. Interestingly, both homeowners and professionals walk by or over stress cracks in walkways and walls unaware of the chipmunk’s role in causing these cracks. In addition to the actual loss of supporting soil, stress cracks alone open the door for secondary damage issues, such as water entry and damage, termite entry zones, and eye-catching cracks for prospective buyers.

I think chipmunks and especially a history of chipmunks seen around a property should be disclosed during real estate transactions. Home inspectors should be alert to these and all other ground squirrels, as should pest professionals.

During routine residential service work, I suggest pest professionals inform their clients as to the structural risks where chipmunks are active around buildings. I’m not advising chipmunk extermination campaigns away from houses, along stone walls or woodsy areas. But near garages, foundations, walkways, garden sheds, etc., the following applies: "Danger Will Robinson — danger!"

The author is president of RMC Pest Management Consulting and can be reached at rcorrigan@pctonline.com or 765/939-2829.