According to a 2018 report of the Cornell Lab of Ornithology, at least 50 million Americans like to feed birds. A 2016 survey by the U.S. Fish & Wildlife Service indicated that 45 million U.S. residents like to watch birds around their homes and in the wild.

Watching birds and feeding birds are popular activities for people of all ages. Bird-watching and bird-feeding aren’t necessarily the same, even though they have some commonalities, such as enjoying birds.

Bird-watching, also known as birding, entails documenting populations of birds, photographing them, sometimes catching them to assess their health and band them, and may entail pursuit of life-time lists of as many species as possible. A popular 2011 movie, The Big Year, tracks three businessmen who seek to set a record for the most avian species observed in the U.S. and Canada during a year, and who “find themselves” in the searching process.

Bird-feeding is contributing to a significant agricultural enterprise—the annual production of a million tons of birdseed, according to the Cornell University Ornithology Lab. About 25 percent of commercial sunflower production is used for birdseed, says a Colorado State University publication:

Millet, cracked corn, sesame seeds, many fruits, suet (solidified beef or pork fat), and niger thistle seed – and which isn’t the weed with the same name–are common foods to attract and feed wild birds. Supplying birdseed has become a multi-billion dollar business annually for agriculture producers, processors, and retailers.

Does feeding birds enhance the spread of avian diseases to farm-raised poultry and other animals? Does the congregation of birds at feeders increase the risk of zoonotic illnesses that can be contracted by humans from animals, such as bird flu? Should people feed birds, thereby expanding the bird population, or allow them to establish their own population controls in their natural environments without supplemental food sources?

Let’s consider each question, starting with the spread of avian diseases. As a psychologist who is also interested in environmental and public health, I am not an authority on these matters, but I can report what has been learned from research and the bird flu epidemic several years ago.

When the HPAI H5 bird flu viruses were detected in North America on British Columbia poultry farms in December 2014, some investigators thought they were spread by wild fowl migrating from Eastern Asia to the Americas. Viruses mutate and spread easily. The first bird flu virus was reported on duck farms in China in 2009; it spread northeastward across Asia.

Eventually the USDA concluded that a likely cause of the virus transmission was insufficient application of biosecurity practices. Air handling systems in large poultry production barns sucked in contaminated air from neighboring production facilities.

In order to stop the spread of the virus, nearly 45 million domestic chickens, turkeys and ducks were euthanized in the U.S. in 2015, and production facilities were decontaminated as the main methods of stopping its proliferation. No humans died.

While it’s possible that migrating wild birds from Northeastern Asia may have transmitted one or more HPAI H5 flu viruses if they flew over Canadian and U.S. poultry farms, it’s more probable that the viruses were brought to North America by human travelers or cargo being shipped overseas.

How detrimental is feeding wild birds? Wildlife ecologist Dr. Daniel Becker found that contaminated bird feeders can spread bird diseases such as conjunctivitis among birds that may have already been vulnerable and would likely succumb to the rigors of migration but instead stayed near a ready food supply.

When asked if people should stop feeding birds, Dr. Becker said, “Absolutely not, there are simple ways to stop the spread of diseases.” One recommended method is to scrub their bird feeders with 10 percent non-chlorinated bleach solution several times yearly.

Researchers at the Cornell Ornithology Lab suggested that if feeding birds was harmful to their health there would be fewer numbers of the species that use feeders, especially during winter months. Instead, there are more birds like house finches and goldfinches, as well as cardinals, juncos and many other species, including some that formerly migrated farther southward during cold spells.

My wife Marilyn and I like to feed birds; our visiting grandchildren share the chores during winter and spring. We cease feeding birds when they begin nesting around late May so that the mothers must consume more high-protein foods like bugs to produce eggs and to feed their hatchlings.

We provide grape jelly and oranges sliced in half to orioles, bluebirds, scarlet tanagers, and indigo buntings after May 5 each year, which is typically when the Baltimore and Orchard orioles announce their return from wintering in southern states and northern parts of South America.

The males arrive first and gently peck our upstairs bedroom window at sun-up, as if to say “We’re back, we’re hungry.” If we don’t feed them promptly they hit our window more forcefully. Smart birds!