Q: I noticed a bird during a visit to western Minnesota that I've never seen before. It was beautiful, with a bright yellow head and a black body. Now I'm wondering if my eyes were fooling me.

A: You were lucky to spot the aptly named yellow-headed blackbird, whose standout markings make it look as if it fell headfirst into a can of yellow paint. According to the Minnesota Audubon Society, this bird's population is significantly declining in our state, and the primary reason is loss of the wetlands and deep-water marshes they need for breeding.

Noisy owls?

Q: We were walking in the woods in a local park at dusk when we heard loud screeching noises. We'd heard that a great horned owl family had nested there this summer, but why were they calling?

A: I'll bet you were hearing the owl family communicating with each other. They may have been making contact after a day of dozing, letting each know where the others were. At that time, the end of summer, the parents were probably still providing hunting lessons, and the youngsters might have been calling something like, "We're hungry, can we starting hunting now?"

A kingly bird

Q: During a round of golf recently a black robin-sized bird seemed to take offense at our foursome. It chirped at us and flew near our heads, over and over. I'd never seen this bird before and wonder if you know what it was.

A: I can think of only one charcoal-colored bird that would act so aggressively: the eastern kingbird. Its Latin name, Tyrannus tyrannus, hints at how intolerant this species is of any kind of intrusion into what it considers its territory. They've been observed harassing birds as large as red-tailed hawks and great blue herons. They're a handsome flycatcher and help control insects on golf courses and elsewhere. You can find out more here: www.allaboutbirds.org/guide/eastern_kingbird/lifehistory. And they shouldn't bother you this fall because they leave early on migration.

Sore throats?

Q: I had many hummingbirds at my feeders this summer, but two of them seemed sick: They'd stick their beaks into the feeder, then tip their heads back as if trying to swallow, but couldn't. After a couple of days I didn't see them anymore. What could have been wrong with them?

A: This is a sad story, and probably didn't turn out well for the hummingbirds. I suspect that they visited other feeders in your neighborhood, ones that aren't as well maintained as yours, and picked up mold or fungus as the fluid fermented. This led to swelling in their throats, inability to swallow and eventual starvation.

This is why experts recommend cleaning feeders and refreshing fluid every couple of days. If you run into neighbors who also feed hummingbirds, maybe at the next block party, you might mention how important it is to keep those feeders clean.

Dirt bath?

Q: I watched a sparrow the other day, rolling around on the ground and flipping dirt in the air. This has happened several times in a dusty spot in my garden, and at first I thought I was seeing a sick or injured bird. After searching online I wonder if it was taking a dirt bath.

A: You're right, birds will bathe in the dust and dirt on the ground, and sparrows are frequent users of this plumage maintenance strategy. They may look as if they're having a seizure while they wriggle their bodies and flap their wings just as they would in a birdbath. The dust helps absorb excess oil, which they then shake off, thereby keeping feathers in optimal condition. This may help control parasites.

Sufferin' sapsucker

Q: A favorite nannyberry shrub is being riddled with holes by a stealthy sapsucker. I'm concerned that the bird will girdle the main stems and cause dieback. And might the holes attract emerald ash borers or beetles that spread oak wilt?

A: The photo you sent shows that the sapsucker is causing major damage to the bark on your shrub, which could lead to die-off. The U.S. Forest Service's pamphlet on the subject advises wrapping the affected area with burlap (temporarily) or hardware cloth. Based on what I've read, ash borer beetles specialize in ash trees, and the oak wilt fungus spreads only to oak trees.

Mallard mania

Q: This was the first time I've ever seen mallards at my lake place act like this: For two days in a row about 40 of them would gather and swim in a circle as if they were herding something to the center. Some of the ducks in the middle seemed to be feeding on something. Were they eating duckweed?

A: That's an interesting observation of mallard behavior, and I think you're right on target with your speculation that they were feeding on something. At this time of year, mallards need a great deal of energy to prepare for migration and consuming insects is a good way to do that. I'm surmising that the mallards had discovered a recent hatch of insects on the water and were greedily herding them into a tight circle to make feeding easier.

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.