Q Is it just my imagination, or are the cardinals extra bright this spring?

A You may have some particularly bright males in your neighborhood. Although we tend to think of all cardinal males as being knockout red, there actually is some variation in their brightness. And some of what you're noticing may be due to location: At this time of year, males are sitting at the top of trees, often facing the sun, to appear as red as possible. Studies have shown that redder males earn better mates and higher quality territories.

Cardinal songs filled with meaning Q Why do cardinals sing so much? I hear them when I go out for the newspaper in the early morning, and they keep it up for hours.

A At this time of year, cardinals are using their songs to accomplish two things: attract a mate and establish a territory. Like many other birds, cardinals are homesteaders and their songs tell other red birds, "This territory is occupied, go find your own!"

With nesting season approaching, they know they're going to need hundreds of insects a day to feed their offspring. Their songs "fence in" enough room to ensure a good supply of this high-energy food for their nestlings. When cardinals sing "Hey, sweetie, sweetie, sweetie," over and over, the opposite sex reads that as an invitation. For other males it means, "Buzz off, or be ready for a fight."

Cardinal attacks reflection Q How long do cardinals live? For eight years a male cardinal has been throwing himself into our windows, mostly in the morning. He does this repeatedly for hours, first at one window, then the others. Could this be the same bird, or is it learned behavior by one of his offspring?

A You certainly have a persistent bird on your hands. This behavior is not uncommon -- many people are perplexed by a cardinal attacking its reflection in a window, car mirror or shiny bumper. Both males and females do this, and most often in spring and early summer when they are obsessed with fighting off competitors. They're confused by their own reflection, thinking another bird is trying to take over their territory. A few weeks from now, as levels of aggressive hormones subside, the attacks should end.

The average lifespan for wild cardinals is about three years, so chances are your windows have been attacked over time by cardinals from several different generations. This behavior tends to be an innate response to a perceived threat. It would be a kindness to put a piece of cardboard over the outside of the window that the bird is attacking. If he moves to another window, move the cardboard. Some birds will harm themselves with this persistent, hormone-driven behavior.

Fair-weather birds Q Starting in February we began noticing a lack of birds visiting our feeders. Now we only get the occasional woodpecker. Any thoughts on the reason?

A Several readers have reported a dearth of birds at their feeders, and I think the explanation lies with the weirdly warm weather we enjoyed. Last year at that time all the wild plants and gardens were buried under several feet of snow. Birds couldn't get at wild seed so they flocked to feeders. The "no snow" winter left plenty of seed out in the open for birds to consume.

Another factor was the winter's relative warmth, with very few below-zero nights. Birds didn't have to consume as many calories to stay alive, so they didn't need to eat as often. However, we're coming into a time when there's very little food remaining in the environment, so it's a good time to keep feeders filled and birdbaths fresh.

Hummers head north Q When will the hummingbirds come back?

A Ruby-throated hummingbirds were reported landing in Gulf Coast states in late February. They're in a hurry to reach the areas where they'll nest for the summer, so the first hummingbirds should start showing up at feeders and flower baskets in mid- to late April. May is really their time, as they race through or settle down into breeding territories. An interesting website, www.hummingbirds.net/map.html, offers a map showing the birds advancing northward.

Who sings 'fee-bee'? Q I think I heard a phoebe singing in February. Did it stay around all winter?

A The bird you heard almost surely wasn't a phoebe, since they're flycatchers and don't return from migration until it's "bug season" in our area. I'll bet that what you heard was a black-capped chickadee giving its "fee-bee, bee bee" call. Chickadees start this in late winter, to help define a territory and call out a mate.

You might want to check out this Cornell Lab of Ornithology website to hear the phoebe call, a sort of strangled sound: www.allaboutbirds.org/guide/Eastern_phoebe/sounds/ac. Compare that with the chickadee song: www.allaboutbirds.org/guide/black-capped_chickadee/sounds/ac.

Eagle eggs Q I see bald eagles sitting on their nest along the Mississippi River -- could they have eggs already?

A Yes, females lay their eggs in March in this area, and both parents incubate the eggs, which hatch after about a month. The youngsters won't leave the nest until they're about four months old, usually in August. It's wonderful that bald eagles are becoming such a familiar sight, and Minnesota has the distinction of hosting the most nesting pairs (1,300-plus) in the contiguous United States. There are a number of nests on public land, invariably near water, in the metro area.

Birds on radar Q Could you run that link again that shows bird migration on radar?

A Here's the National Weather Service's daily map site: http: //radar.weather.gov/Conus/full_loop.php. Concentrations of migrating birds show up on weather radar -- look for the rough circular areas moving northward.

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