Does Bird Feeding Affect Bird Behavior?
Ten common questions regarding the pros and cons of bird feeding.
by Dr. David Bird, contributor for The Backyard Bird Newsletter
Much of the behavior we observe in our backyard birds is centered on the artificial feeders we set out for them. Offering those tasty treats brings the birds in closer so that we may appreciate their beauty and enjoy their antics. Some feel compelled to feed the birds because of a desire to help them out. But not all folks agree with the hobby, questioning whether our artificial feeds adversely affect the behaviors of our birds. In this column I want to focus on 10 common questions regarding the pros and cons of bird feeding.
1) If I feed the birds in winter, will I prevent them from migrating south?
There is no scientific proof that feeding birds alters their migratory habits. Having said that, some scientists believe accipiters like Cooper's hawks and sharp-shinned hawks forego migration in some areas due to the abundance of prey at bird feeders, a behavior called short-stopping. It is also believed that the presence of feeders has facilitated the northern population expansion of northern cardinals, mourning doves, tufted titmice, and others. Certainly the urge to migrate is deeply ingrained in most birds and is mainly controlled by changes in day length. When the days shorten in the fall, hormones induce both restlessness and fattening through increased feeding. In short, when it is time to head south, they go. Some species like swallows will even abandon nestlings in their nests to migrate south.
2) When I attract songbirds to a location on a regular basis, am I serving them up on a platter to raptors?
Some raptors, particularly Cooper's hawks, sharp-shinned hawks, American kestrels, and merlins, frequent backyards containing feeders in search of small birds. Accipiters are especially fond of hiding among shrubs and trees to suddenly dash into a group of feeder birds. But they usually capture the weaker or less fit birds. Whether they kill birds at a feeder or at some other location, keep in mind that it is all part of nature, "red in tooth and claw." Birds of prey are part of the natural landscape and their appearance at your feeders should actually add drama to your backyard. If the birds abandon your feeders due to the presence of a hawk or falcon, it is generally only temporary. If there are no birds, the raptor will move on.
3) If I and/or my neighbors own a cat, should I forego feeding the birds?
I estimate that free-ranging pet cats kill one to two billion birds annually in the world. But not all cats kill birds. If you do have a cat or two hanging about your yard with murder on their minds, keep your feeders and birdbaths out of reach and well away from vegetation where the cats can hide to ambush birds. Using seed trays on your feeders to prevent seed from falling to the ground will minimize the numbers of vulnerable ground-feeding birds. Spraying unwanted cats with water can be quite effective at training them to avoid your yard, and it won't actually hurt the animal.
4) By attracting birds to my yard with feeders, am I increasing their risk of striking windows?
Daniel Klem of Muhlenberg College in Pennsylvania estimates that somewhere between 100 million to a billion birds die from striking glass in North America each year. However, if you locate your feeder either within five feet of your windows or, alternatively, 30 feet away or more, you can minimize the chances of bird strikes. There also exist myriad ways to reduce the amount of reflective surfaces on windows that create the illusion of empty space.
5) Do birds actually need the food I offer in my feeders?
Generally no. They likely do use your feeder as a fast-food outlet in times of food shortages though. At least three published scientific studies have shown nutritional and reproductive benefits to blue jays, black-capped chickadees, and tufted titmice that breed in neighborhoods that are home to plenty of feeders.
6) By offering food to birds, am I helping to elevate squirrel populations?
John Terborgh in his 1989 book Where Have All the Birds Gone? claims that bird feeders are responsible for artificially elevating the populations of squirrels, which are known to be voracious predators of birds' eggs and nestlings. His arguments do make sense to me and they offer a strong case for dissuading these furry rascalssquirrel-resistant feeders, baffles, less desirable seeds such as Nyger, etc.
7) Do feeders heighten the spread of disease among birds?
This is one of the strongest anti-feeding arguments. Although it is true that forcing birds to feed together at common places can lead to increased disease transfer, it is also well known that birds often feed in groups, including mixed-species flocks, in the wild regardless. Good feeder hygienecleaning feeders regularly, offering fresh seed, minimizing feces build-upand generally striving for quality versus quantity of desired visitors can lessen this problem.
8) Should I worry about my feeders attracting pigeons to my yard?
Yes, but not because pigeons are inherently evil. Regrettably, they have gotten a bad rap in the public eye, often being referred to as "winged rats" and "flying bags of disease." Pigeons do not carry any more diseases than other wild birds, but because they have this public stigma, it is not wise for backyard feeder operators to use sloppy feeding practices that attract pigeons and eventually the enmity of neighbors. This can sometimes lead to draconian municipal laws that ban bird feeding altogether.
9) By feeding the birds, am I helping the economy in some way?
Bird feeding is a multibillion-dollar industry. Keeping your feeders up and filled year-round can help small businesses like nature stores survive, particularly in bad economic times. Growing seeds for the bird-feeding crowd has also become a popular agricultural practice, especially in developing countries.
10) Can my backyard bird-feeding hobby be useful to the conservation of birds?
Absolutely yes. In the past decade or so, citizen science has become a major tool used by conservationists to help bird populations. Participating in events like the Great Backyard Bird Count allows scientists to acquire snapshots of how bird populations are faring from year to year, as well as detecting long-term trends. This information becomes particularly critical in the face of climatic and habitat changes.
So there you have it. To my mind, there is only one reason you should offer food to the birds in your backyardto enjoy them!