In nectar wars, orioles can outmatch feisty hummingbirds

Q: I'm happy to have both orioles and hummingbirds sipping the sugar water in my nectar feeder, but the problem is that they're not sharing. It looks as if the orioles drive off the hummingbirds when they come in. Any ideas?

A: Hummingbirds are such feisty little birds, I'm a bit surprised they let themselves be bullied by Baltimore orioles. But orioles are much larger and can easily dominate feeders. How about buying another hummingbird feeder and setting it out in a different spot in your backyard? And if your garden provides plenty of blooms, there'll be nectar for hummingbirds even without having to visit feeders.

To stay or go?

Q: All the birds in my backyard seem to be busy with nesting right now. The question I have is why cardinals don't migrate but stick around all winter, while birds like the tiny house wren do fly away in the fall. Are there ramifications for survival?

A: Excellent question, and in the natural world, everything has ramifications for survival. Let's look at those wrens: Taking two long flights each year exposes them to all sorts of dangers on the journeys. Their average survival rate is around 50% each year. Cardinals aren't exposed to migratory dangers, but the challenges of surviving severe winters mean their annual survival rate ranges from 20 to 50%. But is migration a better option for survival of the species? Those better odds for wrens need to be balanced with the fact that year-round birds like cardinals get first choice of the best territories and have time to develop knowledge about food sources, and other survival factors. I hope ornithology graduate students somewhere are looking more deeply into this question.

Odd trios

Q: All winter long three chickadees visited our feeders together, and I'm wondering whether they're the same gender, or was it two of one and one of the other? And in late spring there were two males and one female mallard in my yard. What's up with that?

A: I think there were two different things going on in your backyard. During winter chickadees are quite tolerant of other 'dees and forage around the neighborhood in small flocks, like the three that you noticed. Since males and females look so much alike, I only know of one way to tell the genders apart: Only females incubate the eggs, so in the unlikely event that you spied a chickadee on a nest, that would be a female.

In the case of the mallards, there never are enough females for all the males seeking mates, so in this case you probably noticed a mated pair and an interloper who hoped to capture the female for himself.

Is all nectar the same?

Q: Do hummingbirds show a preference for native plants' nectar over nonnatives?

A: Good question, and I'd say that hummingbirds don't care whether the nectar they seek is offered by a native plant or a nonnative. However, they are familiar with native plants, such as cardinal flowers, and know the sugar content of the nectar these offer, so they tend to visit natives first. Add in the fact that native plants attract native insects (hummingbirds need insects for protein), and you'll see there's an advantage to planting natives in your garden.

Females will probe all kinds of blooms in search of nectar, pollen and small insects to feed their nestlings, so it's a good idea to have something blooming at all times. Good choices for hummingbirds include lobelias, bee balm, columbine and penstemons, along with colorful annuals like zinnias and salvias.

Nest disaster

Q: A pair of cardinals had a nest with four tiny babies in a small oak in my yard. Then that big hailstorm hit in mid-May and the next day the nest was completely empty. What might have happened?

A: It's a sad thing when birds put so much effort into building a nest, laying eggs, then starting to raise their youngsters, only to be wiped out by a storm. But this is often the reality for cardinals, a species that nests in the open and has a fairly low rate of nest success. (The Cornell Lab of Ornithology has found that fewer than 40% of cardinal nests fledge at least one youngster.) The young birds were probably killed either by hailstones, or, if their parent were driven off by the storm, by the sudden drop in air temperature. Then it wouldn't take long for other birds to discover the little carcasses and carry them off as a source of protein for their own young. Or, predators like squirrels or chipmunks might have found the ruined nest and eaten the young birds. Cardinals nest twice during the breeding season at our latitude, so this pair almost surely started building another nest very soon after the storm.

See or hear?

Q: Robins are very busy running around my lawn as they search for worms. I'm wondering about that famous head tilt they do. What's up with that, are they listening for worms below the surface?

A: Robins rely on their vision in foraging for worms, so when they cock their heads as you've seen them do, they're focusing one eye on the ground. This way, they can see the small entrance holes for worm burrows, and poke around until they find a wiggling catch.

Wreath birds

Q: I kept meaning to take down the holiday wreath, but never got around to it. Now it's getting very dingy but there seems to be some kind of bird nesting in it. How long should I wait before taking it down?

A: Aha, you have encountered the "holiday wreath nesting bird," also known as the house finch. You doubtless heard their beautiful songs earlier in the spring, and they are always happy to find a wreath or hanging basket to hold their nest. After hatching, the young stay in the nest for almost two weeks, so once things get quiet in your wreath, you can take it down and dispose of it. House finches also often use hanging flower baskets to hold their nests, so it takes a delicate touch to avoid spraying the nest when watering the basket. Once the young birds leave, it might be a good idea to take the basket down for a week or two, since house finches tend to re-nest in the same area.

Note to readers: Parent birds could use a helping hand at this busy time of year. Please spray out bird baths at least once a day so birds have fresh water for drinking and bathing, and keep bird feeders filled. And please keep your cat indoors: It's just too easy for felines to pick off helpless youngsters as they're learning to fly. Avoid using harmful chemicals on plants to avoid sickening birds and so there are plenty of insects to feed young birds. Look for active nests before pruning trees or shrubs.

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.