Are bothersome Redwood City scrub-jays exacting revenge on homeowners who took down their nest?

And a reader wonders why birds no longer frolic in his backyard birdbath -- a plastic replacement for a heavy cement version that once attracted flocks.

DEAR JOAN: A few months ago, I wrote that there were no birds in our yard despite years of hummingbirds, chickadees, titmice, etc. You suggested they might be mating and would be back soon.

We still have no birds, but in March, we noticed scrub-jays flying all around the yard and pecking at the birdhouse to make the entrance hole larger. At the same time, we noticed that they were building their own nest in the citrus tree, and we destroyed the nest.

Now they are actively patrolling the yard and threatening all the birds, screaming at us and pooping all over the patio furniture and our cars.

Are there any devices,  like silver spinners, that will keep them away but won’t deter the other birds.

— Kathleen, Redwood City

DEAR KATHLEEN: Sorry that my prediction about the birds return turned out to be wrong, but at least one species of bird likes your yard, and that is somewhat hopeful. Isn’t it?

Before I get into that, though, I need to scold you a bit for destroying the jay’s nest. California scrub-jays are a federally protected bir,d and it’s against the law to destroy nests and eggs. If the nest was just barely in the beginning stages, you can remove the nesting materials. But if the nest is well underway or complete, you need to let it be.

While I forgive your transgression, the jays might not have. They aren’t as intelligent as crows, but they are very bright, and they take things like that personally. That could be why they are harassing you now.

There’s not much you can do to scare away the jays without scaring away the birds you want to attract to the yard. Mylar ribbons and spinners that move erratically in the breeze may help, but other birds aren’t going to like them either. Farmers use sudden, loud noises to deter birds, but that’s not advisable in an urban setting.

The best deterrent is a food-based one. If you’re filling your feeders with a general mix of seeds, sift out any sunflower seeds. If peanuts are on the menu, retire those as well. If there’s nothing you’re offering that the jays care to eat, they won’t be as territorial over the feeders, letting other birds eat..

There’s a lot to be said for trying to get along with nature. You could make amends with the jays by putting out a feeder or two just for them, filled with peanuts or black oil sunflower seeds. Place them on the edge of your property or in the front yard, leaving the backyard for the other birds.

DEAR JOAN: For years, we’ve used a heavy cement birdbath in our yard and had many birds splashing around in it to our delight. However, as we’ve aged, we can no longer manage lifting and cleaning the cement fixture. We bought a plastic replacement but in 3 months, no birds have been seen using it.

— Keith H., Livermore

DEAR KEITH: The problem with plastic or glass birdbaths is that while beautiful, the sides and bottom often are slippery, and the birds can’t get a good footing. Try adding a layer of rough pebbles or stones in the birdbath, giving the birds something to hold onto. Otherwise, look for a new lightweight bath that is highly textured.

Animal Life runs on Mondays. Contact Joan Morris at AskJoanMorris@gmail.com.