A few decades ago, most of the birds that fed in North America's backyards ate weed seeds and insects gleaned from crevices in tree bark. Now they're presented with other feeding options. Nearly one-third of the adult population of North America dispenses about a billion pounds of birdseed each year as well as tons of suet and gourmet "seed cakes." What changes does this largesse impose on our native birds?

 There is surprisingly little research on the effects of feeders on individual species, but the limited studies so far suggest that backyard feeders are not creating a population of dependent wintering birds. For example, researchers Margaret Brittingham and Stanley Temple from the University of Wisconsin compared winter flocks of black-capped chickadees in two similar woodlands in Wisconsin-one left natural and one equipped with feeders stocked with sunflower seeds. After three years of study, they found that winter survival rates were highest in the woods with the feeders -but only during winters with prolonged periods of extreme cold. This suggests that in milder climates, feeders may have little effect on the winter survival of chickadees. The study also found that nesting populations in both woods were similar the following spring. 

Other research by Brittingham and Temple allays the concern that birds may lose their natural talent for finding food and become dependent on the easy life of taking food at feeders. To test the ability of chickadees to switch back to natural food, they removed the feeders from a woodland where birds had been fed for the previous 25 years and compared survival rates with those of chickadees in a nearby woodland where there had been no feeders. They documented that chickadees familiar with feeders were able to switch back immediately to foraging for natural foods and survived the winter as well as chickadees that lived where no feeders had been placed. This was not surprising, since food from feeders had made up only 21 percent of the birds' daily energy requirement in the previous two years. Clearly, much more work needs to be conducted with many feeder-frequenting species throughout their ranges. These studies, however, suggest that winter feeding does not promote dependency.

 Yet anyone who has conducted a Christmas Bird Count in northern latitudes will testify that most wintering land birds are found around bird feeders. That's not surprising, since feeders reduce the time it takes to find food, and the average meal size (juicy sunflower kernels and suet) is certainly larger than tiny weed seeds or wintering insects dug out of tree bark. Feeders may also reduce the risk of predation, since feeder birds spend less time foraging and have more time to watch for predators. However, these benefits can be offset by more exposure to disease, increased collisions with windows, and greater vulnerability to house cats that may lurk near feeding stations. 

Feeding birds is certainly not as helpful as improving backyard habitat through landscaping, which provides food for a wider variety of birds, as well as shelter, nesting places, and perches. But one thing is certain: Feeding helps close the distance between wild birds and people. 

Below, a look at some of the most frequently asked feeder questions, plus recommendations for what you should have in your backyard. 

Does feeding increase nest predation? Some critics of backyard bird feeding argue that feeders bolster the populations of nest predators such as blue jays and grackles, nest competitors such as European starlings and house sparrows, and nest parasites such as brown-headed cowbirds. But an analysis of the North American Breeding Bird Surveys conducted between 1966 and 1996 found that these species are actually declining-along with many other grassland and thicket-nesting birds. In contrast, resident forest birds, including black-capped chickadees, hairy woodpeckers, white-breasted and red-breasted nuthatches, and tufted titmice, are on the increase. Most likely, the regrowth of forest habitats and changing agricultural practices are having far greater effects than backyard feeders. 

Does feeding birds affect migration? Bird migration is triggered by changes in day length, not the availability of food. Birds that frequent feeders usually will not linger past their normal migration time. Stragglers at feeders are generally birds that are injured or that lack migration talents. Most of them will not survive the winter.
 
 

2. sunflower-seed tube feeders If you are going to put out just one bird feeder, this is the best choice. Be sure to select a model with metal ports around the seed dispensers to protect the feeder from nibbling squirrels and house sparrows. Hang the feeder at least five feet off the ground and position it near a window, where you can enjoy the visitors. These feeders are especially attractive to small birds such as chickadees, titmice, nuthatches, goldfinches, siskins, and purple and house finches.

Will birds suffer if feeders go empty in the winter? In most instances, "your" backyard birds have a feeding tour that includes many neighborhood feeders as well as natural foods. Unless you provide enormous amounts of food and live in an isolated location, it is likely the birds that visit your feeders will not suffer if you leave your feeders empty for a few weeks of winter vacation.
 
 

3. Suet Feeder Suet is readily eaten by titmice, chickadees, nuthatches, and woodpeckers. In addition to the regular suet-feeder visitors, wrens, creepers, and warblers occasionally pick at these mixes. You can hang suet chunks from a tree in an onion bag or a half-inch hardware-cloth basket, or in a more durable cage feeder like the one shown here. You can also make your own suet pudding and feeder. Suet puddings are made by grinding and melting suet and adding seeds. (There is no evidence that suet puddings are more attractive to birds than chunks of suet.) Pack peanut butter-cornmeal blends (when you mix the peanut butter with cornmeal it not only stretches the expensive peanut butter but also makes this sticky treat easier to swallow) and suet puddings into the crevices of large pinecones or into one-inch-diameter holes drilled into logs. Hang the pinecones and the logs from poles near other feeders, from trees, or from a wire stretched between trees. Avoid feeding suet when temperatures climb into the 80-degree range; it turns rancid and drippy and may damage feathers.

What feeders should I use? Several feeders offering different kinds of foods reduce waste and minimize congestion. Having multiple feeders in different places will also attract a variety of species, since birds typically feed at different levels. Woodpeckers, jays, nuthatches, chickadees, and finches readily feed in trees, so these will visit higher-set feeders. Likewise, cardinals, towhees, sparrows, and juncos usually feed near the ground. Place feeders close to windows so that you can enjoy the action, but beware of large picture windows that may result in collisions. Avoid ground feeders if there is a risk that house cats will pounce from nearby shrubs. 

Can birds catch diseases at feeders? Diseases such as salmonella can spread at feeders, especially where seeds and droppings mix. Ground-feeding birds, such as doves and finches, are especially vulnerable. To reduce the risk of disease, clean your feeders at least once a year with a 10 percent bleach solution-one part bleach to nine parts water. 

4. Hopper Feeder Hopper feeders provide dry storage for several pounds of mixed seed, which tumbles forward on demand. Position hopper feeders on a pole about five feet off the ground. Hopper feeders attract all of the species tube feeders attract, as well as such larger birds as jays, grackles, red-winged blackbirds, and cardinals.

How can I keep squirrels out of feeders? Avoid hanging feeders from trees and eaves. Place them on isolated poles at least five feet off the ground and as far as possible from your house and nearby trees and tall shrubs, keeping in mind that squirrels can leap as far as six feet. Attach to the feeder pole either an inverted cone with at least a 13-inch diameter, a special squirrel-deterring dish with a 15-inch diameter, or a PVC pipe or stovepipe that's 6 inches in diameter and 18 inches long. Protect feeders suspended from a horizontal wire by threading old records, compact discs, or plastic soda bottles on the wire on each side. 

Is it okay to leave my cat outside as long as I put a bell on its collar? There are about 100 million domestic and feral cats in North America, and these kill about several hundred million birds each year. Cats account for about 30 percent of birds killed at feeders. Cats are such stealthy hunters that they can stalk and pounce on prey without jingling the bell on their collar. By keeping your cat indoors, you'll not only protect birds but also keep the cat safe from disease, traffic, and fights with neighborhood pets and wildlife. 

What do I do if a hawk starts killing birds at my feeder? It is important to discourage hawks from dining on feeder birds, because both predator and prey are vulnerable to accidental deaths resulting from window collisions. If a hawk sets up a regular feeding routine at your feeders, stop feeding long enough to let the smaller birds disperse. Soon the hawk will leave to feed elsewhere. 

5. Thistle Feeder Especially designed to dispense niger seed, also known as thistle seed -different from the prickly garden weed-these feeders typically have tiny holes that make the seed available only to small-beaked finches such as goldfinches, redpolls, and pine siskins. Thistle-seed-dispensing bags are not recommended, since squirrels can easily tear holes in them and waste this expensive seed. Hang your thistle feeder from a tree or place it on a five-foot pole near other feeders, taking care to protect it from squirrels with a special baffle.

How can I stop birds from crashing into my windows? A recent study found this to be the most common cause of death associated with feeders (about 1 to 10 deaths per building each year). Falcon silhouettes attached to windows seem to have little effect. Fruit-tree netting stretched taut several inches in front of the glass is the best approach. 

Will birds stick to metal feeder parts during subfreezing temperatures? Our fingers may stick to metal ice cube trays because moisture freezes on contact with frigid metal. However, a bird's feet are covered with dry scales, so there is no surface moisture to freeze to metal perches. Eyes, tongues, and beaks are usually safe from exposure to metal feeder parts. Rapid reflexes prevent the eye from coming in contact with foreign surfaces, and the beak is protected by a horny, dry surface. 
 

Ornithologist Stephen W. Kress's latest book is The Audubon Backyard Birdwatcher: Bird Feeders and Bird Gardens (Thunder Bay; 1999). Award-winning illustrator Maryjo Koch recently published The Nest: An Artist's Sketchbook (Stewart, Tabori and Chang; 1999).
 
 

Bird Feeding Goes High-Tech   In the age of 100-channel TV, watching the bird feeder has become a high-tech pastime, with remote cameras built into feeders and a new generation of Internet-savvy feeder watchers documenting the action in their backyards and then downloading it.  Consider some of the new feeders: The Bird-Vu Wireless Audio/Video Bird Feeding Station comes with a video camera and recording device that beams all the action at your feeder right to your television, so "you can enjoy the sights and sounds of the birds, up close and personal," the company declares in its brochure (Nature Vision Inc.; 800-295-1546; $499.99). The VR-100 BirdCam Camera, a comparable product except that it comes without the feeder, also allows armchair birders to watch and listen to birds at the feeder or even monitor a nest without disturbing its inhabitants (Video Enterprises; 612-378-2577; $399). Both cameras connect to your VCR, making it easy to permanently capture the image of a rare bird stopping by or to create a video library of backyard visitors. Of course, there are less expensive ways to get a better view. The Songview In-House Window Feeder brings the birds into your home with a shatterproof, one-way mirror that allows you to see them without their seeing you. Plus, there's a convenient hole so you can fill the feeder with birdseed from inside the house (Duncraft; 800-593-5656; $119.95).  What could be more appropriate in today's high-tech world than a scientific survey powered by citizen feeder watchers and broadcast instantly over the Internet? The Great Backyard Bird Count, held for the first time in 1998, welcomes participants to count the birds that visit their backyard, park, or another designated area during a four-day period in February. After they've tallied their birds, they can log onto BirdSource at www.birdsource.org to record their findings, and the data will become immediately available on the Internet. Because the count focuses on common species, birdwatchers of all skill levels can join in the fun. Last year about 42,000 people participated, including many schoolchildren and youth groups, says Sally Conyne, the National Audubon Society's director of citizen science. This year's event will be held February 18-21.  Birdsource also sponsors Project Feeder Watch, which since 1987 has invited people across the United States and Canada to make regular counts of the birds that visit their feeders from November through April. Log onto the Birdsource web site at www.birdsource.org to find out everything you need to know to get started, from buying a feeder to selecting seed to identifying birds. Feeder Watch provides useful information as well as entertainment. Last year, for example, 10,000 Feeder Watchers and Great Backyard Bird Counters documented huge flocks of American robins roaming the northern states in the dead of winter. The reports prompted scientists at the Cornell Lab of Ornithology to analyze the Feeder Watch data, from which they discovered a correlation between snowfall and robin distribution. "Robins were not reported in areas where the snow cover was greater than five inches," says Matthew McKown, Audubon's science coordinator.  "There are many questions that remain unanswered about the health of bird populations," says John W. Fitzpatrick, the Louis Agassiz Fuertes director of the Cornell lab. "The only way to monitor population-wide changes is by harnessing the observations of bird enthusiasts across the continent."  Both Project Feeder Watch and the Great Backyard Bird Count have helped document the expansion of the Eurasian collared-dove, a species that was introduced to the Bahamas in the 1970s, migrated to Florida, and is slowly but surely spreading across the country.  The technical staff at Cornell is still adding features to Birdsource. Soon you'll be able to use your computer to track the expansion of the Eurasian collared-dove yourself, or find out what birds you might see on your vacation to southeast Arizona. "You will soon be able to click on an interactive map of North America to find your own backyard and the birds you'll find there," says McKown.  -Rene S. Ebersole

What's on the Menu

1. Sunflower seed: Black-oil seed is the preferred seed of many small feeder birds, especially in northern latitudes. Striped sunflower seed is also readily eaten, especially by large-beaked birds. Hulled sunflower seed is consumed by the greatest variety of birds; it attracts jays, red-bellied woodpeckers, finches, goldfinches, northern cardinals, evening grosbeaks, pine grosbeaks, chickadees, titmice, nuthatches, and grackles.

 

 

2. Millet: White millet is the favorite food of most small-beaked ground-feeding birds; red millet is also readily eaten. Millet attracts quail, doves, juncos, sparrows, towhees, cowbirds, and red-winged blackbirds.

 

 

3. Cracked corn: Medium cracked corn is about as popular with ground-feeding birds as millet, but it is vulnerable to rot, since the interior of the kernel readily soaks up moisture. Feed small amounts, mixed with millet, on feeding tables or from watertight hopper feeders. Avoid fine cracked corn, since it quickly turns to mush; coarse cracked corn is too large for small-beaked birds. Cracked corn attracts pheasants, quail, doves, crows, jays, sparrows, juncos, and towhees.

 

 

4. Milo, wheat, oats: These agricultural products are frequently mixed into low-priced birdseed blends. Most birds discard them in favor of other food, which leaves them to accumulate under feeders, where they attract rodents. Milo is more often eaten by ground-feeding birds in the Southwest. It attracts pheasants, quail, and doves.

 

 

5. Thistle (a.k.a. niger): A preferred food of American goldfinches, lesser goldfinches, house finches, and common redpolls, niger is sometimes called "black gold," because it costs about $1.50 per pound. Do not confuse it with prickly thistle, a pink-flowered weed used by goldfinches to line their nests. Niger works best in special thistle-seed feeders with small holes that restrict the flow of the tiny black seeds. The best feeders have holes below the purchase to permit feeding by goldfinches, which can hang upside down (and thus excludes the more common house finch).

 

 

6. Suet and bird puddings (reconstituted suet and seed): Peanut butter-cornmeal mixes (one part peanut butter, four parts cornmeal, and one part vegetable shortening; good for winter and summer feeding) or whole and crushed peanuts attract woodpeckers, jays, chickadees, titmice, bushtits, nuthatches, brown creepers, wrens, kinglets, northern mockingbirds, brown thrashers, starlings, and yellow-rumped and pine warblers.