When swans don't look like swans

Q: While walking at Spring Lake Regional Park we saw some swimming birds too far away to identify. They were white, with long necks, but seemed to have darker heads and necks, and I can't find them in my field guide.

A: You've provided a good description of swans, probably trumpeter swans. I can see how you were confused, since swans are supposed to appear to be white all over. But these big water birds often feed by dabbling, plunging their heads and necks under water to forage. The presence of aquatic vegetation and minerals can darken their heads and necks.

Q: I was walking the trails at a park along the Mississippi River when I noticed a pair of sandhill cranes standing in the shallow lake. These cranes were reddish brown all over, unlike the gray sandhills I'm used to. What's the story on their unusual color?

A: The standard answer is that normally gray sandhills often preen themselves by spreading mud over their feathers. If there's enough iron in the mud it can cause a reddish cast to crane feathers. But this raises the question of why do they do it? After some research it sounds as if there's no definitive answer but a likely one is that they seek to appear redder to seem less conspicuous as they skulk through vegetation during nesting season.

Q: Is it just me or was spring migration a big disappointment this year?

A: I know I was disappointed in the lack of migratory birds, especially the warblers.

Two very knowledgeable birders I know also felt that migration was fairly scanty, ascribing it to meteorological factors: Winds were blowing from the south up through Iowa, but from the north in Minnesota. This caused many migrants to veer around our state or to leapfrog over our area. This happens from time to time; we'll just have to hope for a better spring flight next year.

Q: We've been watching a Canada goose who's been sitting on her nest for about three months. Don't geese have an instinct that tells them when their eggs aren't going to hatch?

A: Geese normally sit on their eggs for about a month before hatch time, so there's no chance that these eggs are still viable. Steve Cordts, a waterfowl specialist with the Minnesota Department of Natural Resources, has encountered similar situations and says that maybe the weather was too warm or too cold as incubation began, or the female goose might have left the nest for too long at one point. There's no telling how long the goose will continue sitting on her eggs, but Cordts once monitored a mallard nest where the female was still sitting on her eggs in late September.

Q: What has happened to the nighthawks I used to enjoy watching and hearing in the summer? They have completely disappeared from my St. Paul neighborhood.

A: These handsome aerial artists are now few and far between, especially in urban areas, due to a number of factors. One cause is the plummeting populations of the flying insects that make up their diet (there are fewer and fewer moths due to pesticide use, for one thing). Nighthawks used to nest on flat-roofed buildings, the kind where a roof barrier was held in place by stones, but these have been replaced by smooth coatings that get too hot for eggs to survive. And even when a nighthawk finds a good, flat roof, the increasing populations of urban crows and gulls prey on nighthawk eggs. This triple whammy has drastically reduced the numbers of these birds that we used to enjoy watching as they foraged at dawn and dusk.

Q: I've had a bird singing in my trees for a week, and while I couldn't see it clearly, it was about the size of a cardinal. It was singing "Ricky, ricky, ricky" over and over and it's driving me crazy, not knowing what bird is doing this.

A: Your cardinal-sized bird almost surely is a cardinal. You provided a very good description of one of the repetitive songs in a cardinal's repertoire.

Q: I've never seen this before: Orioles visit the feeder I have hanging from my deck railing, but yesterday a robin came to feed, too, and returned several times. Does this mean he has a sweet tooth?

A: Robins are big fans of fruit — there was a big crowd in my serviceberry in June and a neighbor's mulberry tree is very popular. So, it's not much of a stretch to go from wild fruit to grape jelly. Your robin had probably observed the orioles and maybe house finches enjoying the purple treat and decided to try it. In fact, several years ago, a reader wrote in about a robin that brought earthworms to dunk in her jelly feeder before eating them, which may be the thrush equivalent of slathering mustard on a hot dog.

Note to readers: A number of you sent e-mails in late May and June wondering where your backyard birds had disappeared to. Leaving aside the question of whether migratory bird populations were diminished by adverse conditions in the South this winter, these folks were concerned about their resident birds, the cardinals, house finches, chickadees and woodpeckers. I'll bet the same thing was happening all over the metro (and state), because this is precisely the period when birds spend nearly every waking minute caring for eggs and then youngsters in the nest. Nearly all songbirds feed their young a diet of insects, no matter what they consume the rest of the year. Parent birds were ignoring bird feeders as they busily searched for caterpillars and other insects to bring back to the nest.

This was also a very hot period and birds seem to eat less in the heat. Once their youngsters fledged and the heat abated, I'll bet the birds returned to familiar feeders.

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.