We probably will purchase your mouse zappers, after two years of trapping mice using humane traps and driving them a couple of miles away to a nature preserve wood pile. We can't figure out how they're getting into the garage (and rarely, house) despite three pest control specialists coming out.
Today I heard a gnawing sound in the ceiling of our rec room – this ceiling continues into our garage, which is attached to the house. When I knocked on the wall nearby or the ceiling, the gnawing would stop and whatever it was would make a distinct buzzing sound! This happened quite a few times, so it was not a coincidence that my banging on the ceiling caused it to buzz. It reminded me of a ciccada buzz or even an electrical buzz – but the sound was of some irritated animal. We're in Virginia near DC on a wooded lot on a lake – tons of wildlife, which we love. I've googled for several hours trying to find out if mice can buzz – it's sure not something I've ever read about! I know squirrels can buzz but am not sure if the sound is the same plus it was starting to get dark and I think it was a little too late for squirrels to be out. We can try with a fourth company but are just at the end of our rope.
First, I suspect you have a flying insect either inside the wall or ceiling and second, it's either there by mistake or by design.
Wasps, bees, cicada's, large root beetles and many other flying insects get real active by late spring early summer. And every year around this time many find their way into these homes instead of "out of homes" when they try to leave for the summer. This mostly happens because they make a wrong turn when trying to leave. This wrong turn can lead to ceiling spaces, wall voids and other areas of the home where they can become trapped. In most cases, the buzzing will be heard for a few days and then it will cease due to the insects death. The average home will be used by many insects each fall as they find places to overwinter (hibernate) and stay warm so there is nothing unusual about this happening. And 99% of them leave the home without anyone knowing they were ever there. But if they get caught or trapped, it can make for some odd results and I suspect this could be happening in your home right now.
Alternatively the activity could be quite intentional. There are many insects that readily nest in wood. They are equipped to drill through wood in order to create nests. The short list included CARPENTER ANTS, WOOD WASPS and POWDER POST BEETLES. These pests use wood for nesting and in doing so their drilling will many times lead them to the inside living spaces; other times they'll come right alongside our living space but never quite show themselves. The residents of the home are sure to hear the buzzing and gnawing they make as they work the wood. The most common insect doing this right now is the CARPENTER BEE. If you don't know about this pest, read up on them in our article as this would be the one I would bet is most likely what you're hearing right now. And if you've been seeing them outside the home, around some plants or garden you have in the yard, I wouldn't be surprised if they either have an old nest they're using or if they're drilling out a new nest which is now close to your living space. As you'll learn in the article, carpenter bees drill through wood to create nests. Their nests are usually just a foot two deep. But I've seen them drill for 10 feet or more so nests can get quite large. I also know they'll buzz and chew quite loudly as you can hear in some of our CARPENTER BEE VIDEOS.
Additionally, I've seen many homeowners get their homes painted or "fixed up" and in doing so, they inadvertantly seal carpenter bee nests without first treating them with the DRIONE DUST we have featured in our carpenter bee article. When the eggs in these nests finish eating and pupating, they'll try to emerge. If their exit holes are sealed, they'll start drilling a new exit hole. This new drilling is what will many times lead them to the inside of the home.
So in summary, here are the three options I suspect might explain what is happening at your home.
1) If the sound you're hearing continues to "move" through the space over several days, I would guess you have some kind of insect trying to escape a nest where they were trapped.
2) If the sound stops after a few days and does not happen again, I would say you have an isolated case of something that could fly which got trapped in a wall or ceiling space and was trying to get out but couldn't and died.
3) If the sound continues and stays in the same location, I would say you have an active nest which has an exit hole somewhere to the outside which is allowing whatever is living in there to move in and out. In this situation, the noise will persist at the same spot on the wall and it will last all summer or however long the season is for this insect in your region.
Here are direct links to the information and products mentioned above:
Carpenter Ants: http://www.carpenterants.com/
Wood Wasps: http://www.bugspray.com/article/horntail.html
Powderpost Beetles: http://www.powderpostbeetles.com/
Carpenter Bees: http://www.carpenterbees.com/carpenter-bee-control