Do robins see worms or hear them? What's behind that head tilting?

Q: When I see robins hunting worms on the lawn, they often have their heads turned to one side, seemingly so one ear is closer to the ground. So, I'm thinking they're hearing worms moving around, right?

A: It turns out that researchers have studied the question of which senses come in to play when robins are hunting earthworms, their favorite prey. The results were clear: Sight is robins' key hunting sense — they're looking for worms. With eyes on either side of their heads, robins don't have binocular vision, so they tilt their heads to give one eye sharp focus on a specific spot. Although it looks as if they're listening for worms, they're actually watching for them.

Woodies paired up

Q: I enjoy seeing a pair of wood ducks return to our pond year after year to use the nest box out in the water. It almost seems as if they arrive together. Could that be true?

A: Yes, you're exactly right. Wood ducks usually pair up on their wintering grounds, before they set out on migration. And they tend to return year after year to sites where they've nested before. So, the pair you're seeing this year could very well be the same male and female who showed up last spring.

Stop window attacks

Q: Help! A robin keeps pecking at my kitchen window. Not only is he making a mess on the glass but I worry about him. How can I get him to stop?

A: This is a common behavior among songbirds at this time of year, and cardinals and robins seem especially prone to it. The bird is seeing his reflection in the window and regards it as another robin trying to take over his territory. So, he battles away at his reflection, wasting time and energy. There are even reports of birds attacking windows so fiercely that they break their beaks. To end this behavior, you need to stop the bird from seeing his reflection, and merely pulling curtains usually doesn't do the job. The standard advice is to tape pieces of cardboard on the outside of the window, until the bird gives up and goes back to nesting duties. This behavior is very different from birds accidentally flying into windows, which can result in their death.

Backyard nests

Q: I see many kinds of birds at my feeders, and am wondering how many of them might build their nest in my backyard.

A: That's a good question, and there are many different species of feeder birds that might nest in your landscape. The major factor here is habitat — does your yard offer the conditions that will convince adult birds that it's a safe place to raise their young? This varies from species to species, but cardinals are on the lookout for dense shrubbery to hide their cup nests, while robins often build on evergreens or deciduous tree branches (or ledges or even on top of air conditioners). Blue jays nest in deciduous or evergreen trees, while a ruby-throated hummingbird might build her tiny nest in a backyard tree, if the habitat offers food and water. Bluebirds, chickadees and house wrens might adopt a nest box, but then again, house sparrows compete fiercely for these, too. A great book for learning about birds' nesting habits is "Into the Nest: Intimate Views of the Courting, Parenting and Family Lives of Familiar Birds," by Laura Erickson and Marie Read.

Home store for birds

Q: What kinds of things could I put out to help birds build their nests?

A: You can help birds during nest-building season by providing safe building materials. Natural things are best, advises the National Audubon Society, and it's best to avoid synthetics. Something as simple as raking up little piles of twigs and/or leaves for birds is a help. Pet fur can be good (if a pet hasn't been treated for fleas), as well as grass clippings (if no pesticides are used on the lawn), and straw (available at big box stores). Offer these in mesh bags, in clean suet feeders or draped on trees or shrubs. Things to avoid: dryer lint (crumbles when wet); human hair (can ensnare legs or wings); yarn or string (can become tangled around a nestling), plastic wrap or tinsel. A boon for robins is to have an open patch of ground that gets watered occasionally, to provide the mud needed for the base of their nests.

Life mates

Q: I've been enjoying the cardinals' springtime songs and it occurs to me to ask: Do cardinals mate for life?

A: Cardinals are fairly unusual in the bird world, since a pair typically remains together all year long — they don't split up after the breeding season, as many other species do. The male and female remain as a pair unless one of them dies, then the survivor will seek another mate. This, in the bird world, is the definition of "mating for life." Cardinals have such a frenetic nesting season — a pair raises two broods during the summer — that they need to pair up and begin nesting quickly. Fun fact: Both male and female cardinals sing.

Bad seed?

Q: After I filled a feeder with seed I'd had for a while, the birds wouldn't eat it. Does seed go bad?

A: Birdseed does indeed get old and lose its appeal to birds. Seeds are full of oils, which is why birds like them, and oils become rancid over time. Generally, most seed will remain fresh for about six months, so if your seed is a year old, it's best to toss it in the trash and start over. It's also a good idea to toss any seed left over after winter and start fresh in spring. Seed lasts longer if properly stored in a dry container out of direct sunlight.

Note to readers: After reading about waterfowl "whiffling" to dump air from under their wings in order to land quickly on water, Kevin Wand of Minneapolis sent this anecdote: "This brought back great memories of my naval aviation career. The Canada geese remind me of watching Navy F-14 aircraft trying to land on the back of a carrier. If it was a young pilot, the plane might be all over the place while trying to land, although they didn't do a full barrel roll."

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.