So many people feed birds that a cottage industry of feeders and food types has sprung up. A trip to the nearest Wild Birds Unlimited store will make that clear. Seed feeders are among the most common, with a wide variety of seeds, especially millet and sunflower seeds. Look at the ingredients of a bag of some of the fancier seed mixes sometime to see the breadth.
Suet is another ingredient in the cuisine served in many a yard. This fat-based item has always been especially favored by birds during the low temperatures of winter, but there are now many “no-melt” types that provide food during the heat of summer as well. You can get suet now with just about anything in it, from raisins to insect parts. Suet diversity follows the evolutionary pathway common to all of our consumer items, although it’s not clear how much difference all these additives make to the birds.
Presumably most people who feed birds are sympathetic to animals and nature, and surely the majority are environmentalists. But as such, shouldn’t we be thinking about what effects we are having on the birds and the environment? What are the pros and cons of bird feeding?
It strikes me that there are really two positive aspects of bird feeding. First, we are supporting bird populations (or at least individual birds). This is probably not very important during the summer or at any time when there is plenty of natural food available. Most birds live in places that furnish sufficient food and adjust their migratory behavior to the availability of food.
But there is always the possibility of unusually hard times, when weather phenomena make food suddenly more difficult to obtain. The most obvious example of this would be a heavy snow storm, blanketing the ground and all the potential food on and in it. Think of a finch eating weed seeds or a jay digging up cached acorns. Suddenly, these resources would be unavailable, and the presence of a dependable bird feeder could make all the difference between life and death. This could be called “bird benefit.”
The other important positive aspect of bird feeding is human benefit, to bring the birds closer to us in greater numbers. Birds that come to a feeder daily are in far greater density and variety than we would see just by randomly looking out the windows of our homes. This must be a prime motivator for many people who feed birds. Of course, our gaining a better love of and understanding for birds in this way probably benefits the birds as well.
Are there negative aspects of bird feeding? The seeds that spill from feeders are avidly eaten by rats at night; some of them are out in broad daylight! For those who don’t like rats much, this is a consideration, although they are usually out of sight and mostly out of mind. Many people also consider Eastern Gray Squirrels unwelcome pests at feeders, as indicated by the great variety of “squirrel baffles” on the market.
More seriously, bird feeding does affect the birds. Feeders attract birds near houses, and occasionally a bird will be startled from a feeder and fly into a window with fatal consequences. Of course, many birds strike windows even without feeders.
Our feeders also may attract predators, from bird-eating hawks to cats, and by concentrating the prey at a feeding location, the predators may have an easier time capturing them. This is surely the case for cats. Some have even called these locations “cat feeders.” In addition, parasites and diseases are surely more easily spread when birds gather at abnormal concentrations of their food. Seed-eating siskins and grosbeaks may contract salmonella and even die at feeders during outbreaks of that disease.
Hummingbird feeders are particularly widespread; hummingbirds seem to find them readily no matter where they appear. These feeders have been responsible for dramatic changes in the winter range of some North American hummingbirds, and their presence has allowed Anna’s Hummingbirds to greatly expand their breeding range in all directions, including far to the north.
As a resident species, the Anna’s have to take the consequences of a hard freeze and a feeder-owner without the motivation or opportunity to keep the feeder thawed. Perhaps there are so many feeders that there is usually an alternate one not very far away. One consequence that has not been examined is the loss of pollination by flowers that were formerly visited by migratory hummingbirds!
Bird feeding has even become part of the tourist industry. Numerous sites in the New World tropics feature clusters of hummingbird feeders that attract hundreds of individuals of up to a dozen species of hummingbirds, providing education as well as recreation for nature-minded tourists.
In any case, there is no concrete evidence that feeding birds is either totally good or totally bad for them, so we can use our own judgment to decide. We might not put food out because we are concerned that a bird might fly into one of our windows because of the feeders. Or we might put food out just to enjoy their presence, perhaps even helping them survive a cold snap.