A surefire way to see more birds in your backyard this spring and summer is to offer them more of what they need. Basically, birds are interested in food, water and shelter, but there can be many variations on this theme.

Birds don't all eat the same things. Look at their beaks: Cardinals have chunky beaks, perfect for crushing seed shells. Chickadees have small, pointed beaks, ideal for grabbing, then pecking seeds open. And woodpeckers have long, strong beaks, well suited to pecking at tree bark or suet cakes.

Water, though, is a universal need, and is just as important to birds as food. In summertime, birds need water to drink, but also to bathe in to get clean and cool off.

And since birds are vulnerable to so many different predators, survival means finding places to get out of harm's way. With these points in mind, here are:

6 easy things you can do for birds

Feed them. The more varieties of feeders and foods you offer, the more variety in feeder visitors. Black-oil sunflower seeds are extremely popular with many kinds of birds, and safflower seeds are not far behind. Offer suet cakes (they don't melt in the heat) in summer (as well as winter) for woodpeckers and nuthatches. Chickadees are fans of shelled sunflower seeds, often called "hearts," and finches are drawn to nyger seed, perching on tube feeders to gobble these down. A three-pronged shepherd's hook can hold three feeders at once, and a squirrel guard on the pole will deter squirrels.

Maintain a birdbath. "Maintain" is the operative word here: In warm weather, birds drink often but they also bathe often, meaning the water gets quite dirty. Most advice about birdbaths is too lenient about cleaning them out, advising to do so every couple of days. But after one mud-gathering robin bathes during nest-building, the water is dirty. It's best to clean out your birdbath every day, maybe even twice a day in warm weather. Spray out the old water with a hose, then refill the basin.

Keep your backyard a bit "messy." Birds need natural materials for nest building, things like grasses, bark strips, twigs that fall to the ground, even pine needles. If you're too "Type A" with lawn maintenance chores, birds will have to look elsewhere for building supplies. Avoid raking up every last leaf, too, since many ground feeders spend time turning over leaves in search of insects, seeds and small plants to eat. It's been said many times, and it's true: An expanse of turf grass is a desert to birds.

Plant more plants. Shrubs attract many kinds of birds to hide from predators, build their nests in, and even sleep at night. And many shrubs produce fruit in the late summer or fall, an added bonus for birds. Consider serviceberry, dogwoods and chokecherry. If you have space, planting a tree helps birds, too, because these provide food for bark-gleaning woodpeckers, shelter for all kinds of birds and lookout points for surveying the neighborhood. Evergreens are great, as are oak, maple and hackberry.

Avoid window strikes. Don't accept birds striking your home's windows as "natural." This often leads to death and the cumulative toll in the U.S. is in the millions, if not billions, of birds each year. Locate feeders 30 or more feet from any windows, or very close, within 3 feet or less, so birds aren't building momentum. In summer, screens reduce the need, but naked glass is a killer. There are nearly invisible decals you can use on dangerous windows, or Mylar strips, masking tape, even drawing on glass with a soap bar.

Thwart squirrels. These furry rodents are pests around bird feeders and are the chief reason many people stop feeding birds. Don't let the squirrels win: Place all feeders at least 15 feet from trees or structures, so they can't leap into them. Hang feeders from shepherd's hooks on a pole, so squirrels can't climb to them. You might also want to try "squirrel-proof" feeders. Birds don't feed when squirrels are in feeders, so it's in everyone's interests to keep them out.

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.