Q: Recently, when I was watering the garden with the hose, I noticed a hummingbird sitting on a tomato cage, seeming to enjoy the fine spray and shaking its feathers as if bathing. Have you seen or heard of this before?

A: I've never seen a hummingbird bathing, but that's exactly what this sounds like. These little birds don't immerse themselves in water, as songbirds do, but they like nothing better than bathing in a water feature putting out a fine spray in a pond or birdbath. They've also been observed flying through lawn sprinklers and "surfing" across wet tree leaves after a rain.

Bald birds

Q: Last year we had a male cardinal at the feeder with no feathers on his head, then this year it's both a male and female. I'm concerned that they have mange, or are they molting?

A: It's not unusual for cardinals (and blue jays) to lose all their head feathers at once, instead of the slow process typical of most birds, where it doesn't come to our attention. The Cornell Lab of Ornithology says that this occurs frequently enough in blue jays that it's considered normal and the same is true for cardinals — it's regarded as within the normal range of molting.

No one is quite sure of the cause. It could be due to genes dictating a fast molt, or it could be caused by feather mites or lice. Cardinals with bald heads really stand out because their black skin contrasts with their red body feathers.

To dye or not to dye

Q: Quick question: Is putting red dye in hummingbird feeders harmful to them?

Some cardinals molt all their head feathers at once, making for a shocking sight.

A: I've read that even vegetable-based red coloring can be tough on hummingbirds' kidneys, so that's a good reason to not add it to the sugar syrup. The tiny birds will find your feeder without coloring in their food.

Bird makes P and J

Q: A common grackle comes into my feeder and picks up a shelled peanut, then flies to the jelly dish 30 feet away and smooshes it around in the jelly, before flying off with a messy beakful of peanut and jelly. Any idea what's going on, is it feeding young or itself?

A: The grackle may either be making itself a peanut and jelly treat, or its offspring are the beneficiaries, and the jelly would make peanuts more palatable and easier to slide down a youngster's throat. A few years ago a reader described a robin that would fly to her jelly feeder and dip earthworms in it. I'll bet it was the same inclination, either the adult was adding a condiment to its worms, or it was sweetening them up for a nestling.

Telling wrens apart

Q: Can you tell me how to distinguish male house wrens from females? We're having so much fun watching them around the birdhouses in back.

A: Good question, but the answer is that there's no discernible difference between the two house wren genders, so neither the experts nor I can tell them apart. If you look in a field guide, there's only a single drawing or photo for this species, since males and females look exactly alike.

'Mean' robins

Q: I have a problem with two male robins who constantly harass the orioles and keep them away from the grape jelly. I keep chasing them away but they come right back. Any suggestions for what to do?

A: Those robins have developed a sweet tooth for your grape jelly and don't want to share it, even though you'd probably prefer to look out and see orioles slurping it down. One way to end the conflict would be to take down the jelly feeder for a week or two. The robins may replace their sugar high with other foods, but it's just as likely that they'll return when you put the jelly feeder back up. Another option would be to set out jelly in small batches in two different locations, which may allow orioles and robins to eat in peace.

Crouching raptor

Q: I recently observed a broad-winged hawk sitting in a tree behind my house while being mobbed by several small birds, including a hummingbird. It appeared unfazed by the mobbing but at one point swooped to the ground, spread its wings and crouched there for a few minutes before flying back to its perch in the oak. Any idea what it was doing?

A: I'm amazed to learn from your tale that even hummingbirds will join a mobbing scene to try to drive a raptor out of the area. My guess is that the hawk was engaging in a behavior called mantling to establish its ownership of a prey item. Could it be that the hawk had had a small rodent in its talons, but dropped it in all the commotion? It flew to the ground to make sure its prey was still there and to tell the mobbers to keep away.

Secretive singer

Q: My wife and I have been perplexed by the magnificent song of a small bird we hear while out for our daily walk. It hides very well but I caught a far-off photo of the bird and am attaching a video that includes its song. Any help will be appreciated.

A: The sounds on the video you sent clearly identify your singer as a warbling vireo, a small, nondescript bird with a rich, burbling song, often running up to 15 notes. They're a migratory bird and flood in each spring to build nests, usually along a lake or pond, and as you noticed, they're very challenging to spot. You could visit the Cornell Lab of Ornithology All About Birds site and type in "warbling vireo," then click on "sounds" to match your tape with their recordings.

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.