Squirrels are not cute; wasps are not fuzzy.
You may not realize it, but a veritable Disneyland lurks within the walls of your old house: every critter imaginable is running amok in your framing, and they’re most grateful for your hospitality. How many of you have lain awake at night listening to the pitter-patter of little mouse-feet and hoped that they weren’t chewing on the wiring; it’s difficult to sleep if you’re waiting for that sizzle-popping sound while the circuit to your clock radio suddenly goes dead.
Old houses are especially prone to these uninvited guests, as the many gaps in their foundations and cornice moldings offer entry that new construction might not afford. An animal’s journey into your home usually starts with the first cold days of autumn, and it seems like the little fellas usually wind up staying well into spring, seeing as you’ve provided food, shelter and often, a nursery for their offspring.
When dealing with pests, it’s best to split the subject into two categories: Bugs and Wildlife. Insects are far more detrimental to the actual structure, as mammals, birds, reptiles and amphibians, 
while they may make life unpleasant, tend to leave the house standing, if just a bit smelly.
With wildlife, one usually becomes aware of their presence either by the noise of them attempting entry and nesting, or through the odor of their waste. Nothing rivals an upset skunk discharging beneath your porch, although I have neighbors who were driven quietly mad by a pregnant squirrel who spent many early mornings trying to chew her way into the eaves situated next to their bedroom. Raccoons build nests in uncapped chimneys, and aren’t discovered until Thanksgiving Day, when you’ve decided to light the first fire of the fall because your entire family is assembled. I’m not going elaborate on the actual scenario that ensued, but neither man nor beast was especially thankful on that particular day.
Due to the fear of rabies, or just not getting bitten or severely clawed, larger creatures like skunks, possums, raccoons and step-children are best eradicated with the “have-a-hart” type traps, (with the exception of the latter pests, for whom the use of spring-jawed, leg-hold traps are permissible and encouraged.) These do not always have to be purchased, but are often rentable from stores or available on loan from humane societies or animal pounds. Should you successfully ensnare one, remember to free it far, far away from your property; I suggest an ex-spouse’s garage, just to let them know that you still think of them from time to time. As satisfying as the use of firearms or poison might be in pest elimination, bear in mind that you don’t want something that large rotting away in some remote, unreachable area of your root cellar where, wounded, it crawled off to die.
Mice are a common problem, especially in fall, as they try to establish winter quarters in the warmth of your home. Speaking from personal experience, the snap-traps only catch the stupid ones, thereby weeding out the rodents with inferior genes. We are thus creating a master race of clever uber-mice that delight in meticulously licking the bait off the traps and going their merry way. I have found that the glue-traps contained within a covered cardboard tube are most effective in catching these cheeky rodents.
Flying animals, namely pigeons and bats, produce copious amounts of waste that is not only odious, but it a health threat to humans. These pests are able to work their way into the tiniest cracks of your attic. Bats do have a benevolent side, as they’re voracious insect eaters. The best way to evict them is to tighten up any loose trim or cracks, and remember to use precautions when coming in contact with their waste. If you have a large bat colony or pigeon flock, professional help will be required.
Wood-destroying insects are one of the greatest silent enemies to old houses: often, they’ve done their damage before you’re even aware of their presence. I was going to replace a rotted trim board on a porch’s face beam one Sunday afternoon, only to discover that this thin piece of pine concealed a carpenter ant colony that had bivouacked in the entire length of the 6″ x 10″ timber. This meant that the porch roof had to be jacked for access, the brick piers had to be rebuilt, as they had crumbled as soon as the load was taken off of them and thenof course the railings had to be rebuilt. Voila; a summer’s worth of weekends were shot to hell.
While termites are not unheard of in this part of the United States, they are not as common here as they are in the rest of the country. We northeasterners must contend with the Powder-post Beetle and the Old House Borer (the latter of which has been used to define this writer and his work). These insects produce larvae that chew through the exposed timbers of a house, leaving fine, flour-like sawdust as their calling card. Look for tiny holes in the wood, especially in areas like the sills, and test for punky wood with a screwdriver. The confirmation of these pests and their removal is often the realm of the professional exterminator.
Another detrimental generator of sawdust is the Carpenter Bee. This insect is actually quite fascinating to watch, if it weren’t for the fact that it’s eating your house. I first became aware of them when I was walking by an unfinished piece of pine trim on an exterior. I became aware of little piles of sawdust on the porch floor, just as if I had forgotten to sweep up after drilling. Looking up, I saw three perfectly round, 1/2″ diameter holes bored randomly into the board. Perplexed, I glanced into them, only to realize that the bee who had created them was eyeing me in return.
Calling in the Pros:
With insects, you have a chance to battle them on your own if you can eliminate the nest and the food source. You’ll have to rip out the deteriorated wood, and store-bought insecticides will help with minor infestations, but there’s a time when we each have to admit we’re out of our league. Persistent infestations or inaccessible ones, such as internal wasps nests (this includes yellow jackets) that cause swarms, invariably during cocktail parties, have to be dealt with by those with skills and weapons beyond the average homeowner. This includes the larger outdoor nests as well. Beer-fueled nocturnal attempts by homeowners using extension ladders and trash bags, all illuminated with flashlights clenched between teeth, usually winds up involving splints and Epi-pens.
Our staff features writer, Dan Cooper has been working on old houses for over 20 years, and also writes for Old House Interiors, Period Homes, Cottages and Bungalows amongst other magazines on the subject of architecure, antiques and design.