Herons and egrets sometimes share a rookery

Q: At the heron rookery at Marshall Terrace Park in northeast Minneapolis, we noticed that the herons seem to nest on one island and the egrets on another. Do herons and egrets ever live together, or do they keep strictly to themselves?

A: Excellent observation and question, and the experts say that great blue herons and great egrets often build their nests in the same stand of trees. This is called a mixed colony, and might include other birds, such as cormorants, as well as those tall wading birds you mentioned. Or, as you observed, they may nest separately, sometimes in close proximity to each other.

'Cat whiskers'

Q: I recently took photos of a gray catbird and in looking at them on the computer I noticed some "whiskers." I'd never seen this before and did some research. The whiskers are called rictal bristles and are found on some groups of birds, including flycatchers. Whiskers on a catbird, how fitting!

A: I hadn't been aware that catbirds have these bristles, either, as they're not very noticeable, and good for you for researching it. After doing some reading myself, I've found that many bird species have these stiff, thin feathers around their beaks, especially nocturnal species and those that are insect eaters. In fact, it used to be thought that such bristles helped a bird scoop insects out of the air, but that idea has been discounted. The current thinking is that they perform a sensory function, providing information about the environments they touch, much like a cat's whiskers do. Other birds that have these bristles include house wrens, many hawks and owls, eagles, ravens and crows, blue jays, warblers and others.

Bird with yellow head

Q: We spotted a yellow-headed blackbird at our feeders. We had never seen one before and a source lists them as rare in this area. What can you tell us about them being in Minnesota?

A: It must have been quite a sight to see this handsome but uncommon bird at your feeders. Our prolonged, cold spring seems to have encouraged all kinds of birds to try feeders for the first time. This species can be found from Wisconsin westward. The yellow-headed isn't abundant or easy to spot in Minnesota and prefers reedy lakes and ponds for nesting.

Suet in summer?

Q: What's your advice about feeding suet during warmer weather? My woodpeckers love it but I have heard mixed opinions.

A: Good question, and suet can be a problem in warmer weather. We should never offer raw suet after outdoor temperatures rise above freezing: It melts and the fat can get on feathers and impair their ability to keep birds clean and dry. The rendered suet cakes don't melt as easily but still become very soft on hot days, and a great deal gets dropped on the ground. Parent birds make good use of suet for feeding nestlings, and it saves them time that they'd have to spend hunting down insects for their chicks. But I take down my suet feeders in July and August if we're having a hot summer.

Night sounds

Q: We've been hearing the sounds of a whip-poor-will at night and wonder whether those are mating songs.

A: You're very lucky to be able to hear the calls of this unusual bird, related to the night hawk. (Hear whip-poor-will calls at AllAboutBirds.org, type in the bird's name, then click on "Sounds." This bird was named after the calls it makes.) Their population is in steep decline and they're heard less and less often in the woody areas where they prefer to hunt and nest. They're active at night as they pursue flying insects, and yes, the sounds you heard are made by a male seeking to maintain a territory and attract a mate.

Jumpy geese

Q: We came across a group of Canada geese in the river and they were turning somersaults! This was different from bobbing for vegetation and we could not for the life of us figure out what was going on. Any ideas?

A: I ran your question by Steve Cordts, a waterfowl specialist for the Minnesota Department of Natural Resources, and here's what he says:

"I've seen plenty of geese do that while bathing (or at least that's what I think is going on). You wouldn't think that a bird that lives in water would need to bathe much, but they do."

Disappearing wrens

Q: Some wrens took over our bluebird house and over a couple of days they packed it with sticks. But then they disappeared, so we checked the box and it's stacked with sticks to the top but there are no wrens. What do you think happened?

A: House wrens have the habit of building a number of starter nests around their territory, apparently an effort by the male to entice a female to be his mate and use one of the nests. It's a bit strange that they seem to have built a complete nest, then disappeared, which suggests that something happened to one or both birds, possibly an attack by a predator.

Too sweet?

Q: We put out grape jelly for orioles and other birds, and many kinds of birds pop in for a taste. But a neighbor told us that commercially made grape jelly is not good for birds, due to the high sugar content and artificial coloring. Is this true, and is this an area where "all things in moderation" might apply?

A: Good question, and I think you're right that jelly isn't harmful if eaten in moderation. Grape jelly is much sweeter (usually through the use of high-fructose corn syrup) than natural foods, but if orioles and others use it as a supplement to more natural foods, they should be fine. I know of people who buy only jelly made without the high fructose syrup and it would be worth the effort to track this down. Small containers of jelly are best, to reduce the chances of birds falling in and getting their feathers saturated with this sticky stuff.

Laura Erickson, renowned bird author and birder, wrote in her blog that she puts out only small amounts of grape jelly each day, because insects tend to fall into it and bacteria probably thrive, too. Also, some birds don't practice moderation and gobble jelly all day long and teach their offspring to do the same, to the exclusion of foods that are better for them. There's no getting around the fact that grape jelly isn't a natural food. But in spring, when there is no fruit available in the natural world, many birds welcome the stuff. Erickson offers an interesting idea: How about setting out grapes for birds, instead of jelly?

Note to readers: Molly Jo Miller sent a description of an amazing sight in early June: "A male scarlet tanager was at our suet feeder. A male ruby-throated hummingbird zoomed in close to check out what kind of delight this brilliant red could provide. As he got close, he pulled up and I could almost hear his brain screaming, 'Divert, divert, divert!' As he braked his ruby throat flared like a red stop sign, and off he went."

St. Paul resident Val Cunningham, who volunteers with the St. Paul Audubon Society and writes about nature for a number of newspapers and magazines, can be reached at valwrites@comcast.net.