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September 10, 2007
More than you ever wanted to know about bats

Russell used to spend hours trying to get a snapshot of a bat. This is the closest he ever got.

We have known for years that we have bats on our mountain. From the earliest days when we camped in tents – before the foundation for the house was ever laid – we would experience the same ritual every evening. First, when the afternoon cooled down into evening, the mosquitoes would come out. Then, at about dusk, the dragonflies would come out and feast on the mosquitoes. Finally, as it began to grow dark, the bats would come out and feast on both the mosquitoes and the dragonflies.

We have known for months that we have bats in our house. Or at least a bat. It began earlier this summer, when we had just sat down in the evening to watch a DVD. A bat deftly and silently flew in front of our faces in the darkness. We assumed that the bat had somehow flown in through the open front door and was helplessly trapped inside. We opened all of the windows and even put a light outside to attract it. After awhile we saw it no more, and assumed that it had successfully escaped.

A few weeks later, the same thing happened again. Still assuming that it was getting in through an open front door, we began to get very careful about leaving the door open, especially when the lights were on.

Over the next several months, we sealed the house but kept seeing the bat, and it dawned on us that perhaps we had a bat living in the house. We began examining the inside rafters both upstairs and downstairs, but couldn’t spot any roosting bats.

Finally, at the end of July, Russell climbed on top of one of the upstairs walls and shined a flashlight into a crack between two ceiling wedges. There, fast asleep, was a bat. It suddenly dawned on Russell that all of the rodent droppings we kept finding on the floor weren’t from mice – they were from bats.

In a crack between two ceiling panels above the hall bathroom, we finally found our culprit

A few days later, when we had our contractors’ reunion dinner, we picked everyone’s brains about bats. We learned that one should think of a bat as a small mouse that just happens to have wings. A bat – like a mouse – can squeeze itself through an opening as small as a quarter.

We asked how to get rid of bats. One contractor told us to shine a fluorescent light at the spot continuously for weeks. Another contractor told us that wouldn’t work. He once had an infestation of bats that he tried eliminating with lights, loud music, etc., etc. How did he finally get rid of them? He ended up dismantling his entire roof and installing a new one.

With our newfound knowledge, we took another look around the house. We knew where the bat was roosting, but we didn’t know how it was getting in and out of the house. (We realized that it must be getting out; otherwise it couldn't have survived this long.) Upon closer examination, we discovered that at the very tip-top of the ceiling – where all eight rafters come together – there were a series of openings that went all the way through to the roof. And the roof cap, of course, was simply a piece of squashed-down sheet metal.

On the inside of the house, the ceiling apex has several gaps that lead right out to the roof

On the outside of the house, the roof cap is simply a piece of tamped sheet metal, providing lots of little openings

Back in the Bay Area, Russell did his usual Internet research, typing “how to get rid of bats” into various search engines. The consensus was that you should not try eliminating bats yourself; you should hire a professional. Of course, all of these Internet sites were written by bat professionals.

Here is a sample "horror story" from one of the many bat eradication Websites.
(These photos are courtesy of www.247wildlife.com/batjob.htm)

(As a side note, Russell also learned how to tell mice droppings from bat droppings, despite their similarity. It involves closely examining the droppings for traces of small insects. Gail was neither curious, interested, nor amused.)

Gail’s idea was for us to put a butterfly net in front of the crack and start poking the crack with a stick. Of course, “us” meant “Russell.” Russell had a different idea.

In mid-August, we returned to our mountain house armed with several cans of spray-foam insulation. We waited until after dark, when we knew that the bats would be out and about, and we began spraying every crack that we could find in the ceiling. Of course, “we” meant “Gail.”

Somehow, Gail is always the one who gets the opportunities to overcome her fear of heights and edges. Note that she is wearing a safety harness.

We sprayed every crack between ceiling wedges, between walls, and between walls and ceilings. As we departed for home, we had no idea if we had sealed the bat inside or outside of the house. Only time would tell.

Two weeks later at the end of August, we returned. The good news is that we didn’t find a dead bat on the floor when we entered the house. The bad news is that when we sat down to watch television that evening, two bats flew by.

We had obviously missed an opening. The next day Gail scoured every nook and cranny once again, and found a small spot she had missed: at the top of the lower-story wall behind the stairwell. She stuffed it full of insulation.

The last little hole, under the stairwell – coincidentally, just about the size of a quarter

We have now been up for another weekend since then, and we have not seen any bats (dead or alive) in the house. We think we’ve finally succeeded.

We still have one more task, unfortunately. At some point, we will need to climb up on the roof, remove the roof cap, and see what’s underneath. At the very least, we may have to vacuum out a whole bunch of bat poop. At the very worst, who knows what we will find up there?

Gail, after her experience spraying insulation into the rafters, has volunteered Russell for this next task. Russell, in turn, is waiting until our friend Steve is available again in a few weeks.

The ceiling crack and apex, respectively, now stuffed with spray-foam insulation


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