I saw remnants of mud above this pillar and thought it was from the wasps we see around, so I was getting ready to spray it. But thankfully before spraying, we saw Barn Swallows landing there.
When we sit on the porch, they make it clear that we’re not welcome. Though my video did not capture it. The Swallows would crawl down into the pillar, and when doing so, we could hear the hungry baby birds.
After inquiring from others, I’ve learned Barn Swallows can be aggressive pests, but the good news is they love insects. Therefore, dear Swallows, you are welcome to stay. Now go get those darn wasps and those ticks. 😁