DEAR JOAN: Bees are constantly falling into our swimming pool, and, unless discovered and “rescued” by a human, drowning. Is this a problem with natural waterways such as rivers and lakes? If so, millions of bees must die in this manner nationwide.

Or is it that our pool is largely surrounded by vegetation that attracts the bees, while natural waterways are differently located?

Merlin Dorfman

San Jose

DEAR MERLIN: The problem with bees drowning in swimming pools or birdbaths is that the water doesn’t come all the way up to the top of the vessel.

In natural settings, including rivers, streams, creeks and lakes, there are places for the bees to sit or stand and drink. In swimming pools and birdbaths, they have to try to drink while hovering or sit on the edge and try to reach the water. You’re witnessing what happens. The bee falls in and can’t then climb the steep sides to escape.

You can give the bees a break by using bee preservation floats in your pool or birdbath. (My favorites are handmade in Washington, www.glassgardensnw.com.) They give bees a nice platform. You also can install some in your pool. They float along, much like a skimmer, and they have a gentle slope that allows the bee — or other insects and frogs — to climb out, dry off and go on their way.

DEAR JOAN: I read the letter from Jack Pease about bats roosting under the roof of his cabin and want to offer the information on our website, Bat Conservation International, www.batcon.org/buildings.

Exclusion (plugging holes, but also installing exclusion devices) really does work, and is the only real and effective solution to bats roosting in buildings; however, it does take some time and effort to identify all entrances and exits.

For exclusion devices, we prefer the use of tube-type devices that can be made from PVC pipe or empty (and very well cleaned) caulking tubes, or purchased commercially. The netting option is something we prefer to phase out of our instructions for the very reasons implied in your text: People use the wrong size netting, which is either ineffective or kills bats.

It’s also important to raise awareness of timing when excluding or evicting bats. From April through August, there may be flightless pups present, so evicting adult bats can leave pups to starve, creating more problems for the homeowner as well as causing pups to suffer and die.

Ultrasonic devices are often expensive and there is no evidence that they work; we don’t recommend the purchase of these heavily marketed, essentially useless devices. Mothballs (their ingredient, naphthalene, is the only chemical registered for use against bats) is a human carcinogen, and using them in the volume necessary to detract bats is a health hazard for humans.

And finally, a word about artificial roosts: Many people prefer to keep bats around their yards for their pest-control benefits, and this can be accomplished by installing a bat house in advance of an eviction and exclusion. This serves the purposes of giving them a new place to live that is not in your house, allows them to continue catching insects in your area and also may keep them out of your neighbors’ attics. Here’s a link to our bat house pages: www.batcon.org/bathouse.

Thanks for allowing me to weigh in on the subject.

Dianne Odegard

Austin, Texas

DEAR DIANNE: Thanks so much for the great information. For those who might remember the original question, I didn’t recommend exclusion because it sounded like the bats were roosting under the eaves, not in the attic.

Readers with bat issues should check out the website. It’s a good one.

Contact Joan Morris at jmorris@bayareanewsgroup.com.