Q: Do you have any idea why we're seeing so many blackbirds and grackles at the feeders this year? They eat up so much food and other birds don't visit when they're around. The only thing that seems to help keep them away is to stop feeding sunflower seeds, but then I miss out on the cardinals and grosbeaks.

A: I'm not sure why there are so many blackbirds around this year, but the same thing is happening at my feeders. They gobble up the suet cakes and peanuts so quickly that we need to refill the feeders nearly every day. Like you, I could take the feeders down, but don't want to deny the woodpeckers and chickadees their meals, so have decided to just wait the blackbirds out. They should be moving off to migration staging areas outside town fairly soon.

Mallards make mess

Q: How can I keep the mallards from pooping all over my dock? Decoys don't work and tying string around the perimeter of the dock hasn't stopped them. I'm at my wits' end.

A: Sorry to hear that the mallards are making a mess of your dock, but there's not much that can be done, unless you have a dog or two that would spend hours patrolling the area. Ducks need to molt new flight feathers at this time of year, and they drop all their wing feathers at once, before growing in new ones. This means they temporarily lose the ability to fly and are vulnerable to predators. They spend a great deal of time on or near shore, hence their affinity for your dock. I've seen the "poopy" boardwalk thing at nature centers, too, indicating that the ducks feel there's safety in numbers. Once their flight feathers molt back in, they'll depart, giving your dock — and you — a break.

Bird foodies

Q: After watching crows pick over the foods we set out for them, seeming to prefer some over others, I am wondering if birds have taste buds and taste preferences.

A: This is an excellent question and I learned some things in formulating an answer. Birds may have only about 5 percent as many taste buds as we do, but this doesn't necessarily mean they have a crude sense of taste. They may be best at detecting sweet, sour and bitter tastes, although there hasn't been a great deal of research into this sensory realm for birds. Much of what is known comes from studying mallard ducks, which can tell a normal pea from a spoiled one, for example. And we know that nectar-sipping birds, like hummingbirds, can detect different levels of sweetness in nectar.

Orioles, catbirds and house finches must be able to taste grape jelly, since they favor it so strongly. And strangely enough, a number of species of birds are said to relish the taste of bacon (found in some homemade suet). As for what your backyard crows are up to, as a species that eats just about anything, it must be a help to be able to taste the foods they're trying. They may find some foods bland, while others, such as peanuts and suet, taste better to them. All in all, I'd say that taste is not as important as their other senses, such as sight and hearing, but they are able to taste and doubtless do develop food preferences.

Tanager territory

Q: Where do scarlet tanagers go to nest? I see them in the spring but not after that.

A: These electric-red birds nest in deciduous forests all across Minnesota (except for a small patch on the southwestern border). We don't see them after migration is completed because they're very secretive and no longer make their distinctive, raspy call.

Jelly for nestlings

Q: A pair of orioles and a catbird have been coming to my grape jelly feeder several times a day. They eat and then depart with full beaks as if they might be supplying their youngsters in the nest. What do you think?

A: Thanks for providing this insight — I've always read that orioles abandon jelly feeders after they have nestlings so they can raise youngsters on an insect diet. Sounds like your backyard orioles and catbirds are varying the standard diet a bit.

Wrens move in

Q: It looks like wrens are moving into my bluebird house, based on the twigs I see stuffed in there. Does this mean no bluebirds for this year?

A: If wrens decide to use your bluebird nest box for themselves, you'll have to wait them out — their nesting cycle takes about a month. Once their brood leaves the box, however, the wrens will probably move off to a new nesting site. That's the time to clean out the nest box and hope a bluebird pair adopts it to raise their second brood of the season.

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.