Q: The crows in my neighborhood put on quite a show this fall: For weeks at a time there were about 40 of them in the area, calling very loudly as they stalked on the boulevards and pecked at something in the street. What were they up to?

A: Sounds as if they were eating tree seeds, such as acorns, that dropped onto the boulevards or in the street, and were digging for worms and beetles in the grass. Just to be sure, I checked with someone who really knows crows, Kevin McGowan at the Cornell Lab of Ornithology, and he agrees. “Crows eat acorns and they search for invertebrates in the leaf litter,” he said, adding, “I’m not sure what all the calling was about, but they do like to talk.”

Seed starved?

Q: I like to leave my perennials standing to provide food and shelter for birds, but this fall I cut the heads off my phlox plants to stop them from taking over any more of the garden. I provide seed in feeders but would the birds maybe have liked the phlox seeds?

A: Phlox is one of those “big elbows” plants that tends to expand in our garden beds. It’s also prone to powdery mildew, so it’s a good idea to cut it back and rake up any leaves that fell. Yes, birds will eat phlox seeds but you more than make up for the loss by providing seed in feeders.

Wet or dry?

Q: I’m trying to decide whether to keep the birdbath going during the cold weather ahead. Any advice?

A: If you have a birdbath heater, it’s a very good idea to maintain it to offer open water for your backyard birds. Seed eating is a very thirsty business, and birds need to bathe, except on the coldest days, to keep their feathers in top condition. If feathers become clogged with dust or debris, they don’t insulate as well, so birds appreciate ice-free water sources. It’s a bit more work keeping a birdbath filled and clean in winter, but pouring in water from a bucket does the trick.

Missing ’dees

Q: Chickadees raised their family in our birdhouse this spring, and it was fun to see the many youngsters at the feeder and birdbath in the summer. But now I only see three chickadees and wonder whether the others moved away.

A: It’s possible that a few of the newly minted chickadees moved off into new territories, but it’s more likely that you’re observing the iron hand of bird mortality in your backyard. With so many dangers and predators in the world, only about half of a nest’s fledglings survive into fall. And then half of those young birds won’t make it to spring. So if your birdhouse produced eight new chickadees, two might reach their first birthday.

Musical sounds

Q: I was hearing the most beautiful, warbling song this fall, but couldn’t find what bird was singing.

A: I’ll bet that you were hearing a male house finch, a bird that can be very vocal late in the season. They do have a beautiful song, one that can stop people in their tracks as they pass by (hear the house finch here: http://bit.ly/2AdIaDJ).

Not a deterrent

Q: I’m worried that if I get a birdbath heater it will cause some birds not to migrate. Is that true?

A: No amenities we provide, whether water or food, will affect healthy birds’ urge to migrate. They get their cues from the natural world, primarily the ever-shorter days, which trigger hormonal changes leading to a feeling of restlessness, which triggers their departure. So no, providing a reliable source of water won’t cause migratory birds to stay around your backyard.

Glass tapper

Q: For several weeks in late fall a flicker was tapping on our windows occasionally. I am aware that male birds will do this in the spring if they think they’re seeing a rival in the glass but can’t imagine why the bird is doing this in the fall. Any ideas?

A: This is unusual behavior for this time of year, since birds aren’t as territorial in autumn and aren’t very interested in driving off competitors. I wonder if the flicker is seeing something inside the house that intrigues it, possibly a plant or other object. It’s also possible that this is a young bird who’s been captivated by its own movements reflected in the glass, or it just likes the sound that glass-tapping produces. It’s fascinating to think about and is more evidence that birds can always surprise us.

St. Paul resident Val Cunningham, who volunteers with the St. Paul Audubon Society and writes about nature for local, regional and national newspapers and magazines, can be reached at valwrites@comcast.net.