This article has been corrected.

A 2014 US Center for Disease Control and Prevention (CDC) report (pdf) found that, between 2009 and 2012, 9% of Americans were using a prescription antidepressant at least once a month. Now, a sizable bunch of birds are too.

(Hold onto your lunch.) New research has found that Prozac, one of the most commonly prescribed antidepressants, can “significantly alter the behavior and physiology” of some bird species, The Guardian reports. The study in question concluded that wild starlings, when fed wax worms injected with levels of fluoxetine (the generic name for Prozac) equivalent to what the birds might be exposed to by “feeding on invertebrates at a wastewater treatment plant,” showed “conspicuous changes in foraging behavior.”

That’s right—birds are getting dosed with Prozac by eating worms in your poo.

Pretty gross, yes; but why does it matter? According to Dr. Kathryn B. Arnold, one of the researchers involved in the study, wild starlings that ingest too much fluoxetine alter their instinctual feeding patterns from two large meals a day to continuous “snacking.” Arnold told The Guardian that this change in feeding habits could affect the species’ ability to dramatically modify its weight in accordance with the seasons—fat for winter, trim for summer. Continuous ingestion throughout the day generally makes for heavier birds all year round, which also makes it more difficult for individuals to escape predators. Prozac, in effect, might wipe out populations of starling in and around waste-treatment plants, which could be devastating to local ecosystems, given that starlings are such avid insectivores.

Birds aren’t the only creatures at risk for Prozac-induced problems. In 2010, National Geographic reported on a study in Aquatic Toxicology which linked high fluoxetine levels in coastal waters with erratic behavior in shrimp. “Shrimp normally gravitate toward safe, dark corners. But when exposed to fluoxetine, the animals were five times more likely to swim toward a bright region of water,” the study found; leaving them at abnormally high risk for predation. Shrimp are a staple of coast-water ecosystems, particularly in fragile estuary zones. A drop in population would be devastating—and all too likely if shrimp continue to get hopped up on dissolved Prozac.

Trace aquatic levels of other drugs—particularly endocrine disruptors like birth control pills, steroids, and tamoxifen (for hormone therapy)—are contributing to a population-rise in “intersex fish,” disrupting mating patterns and unbalancing populations of breeding-age adults. According to a 2013 article in Nautilus, “In studies done all over the world, normally male fish downstream of wastewater plants appear to be growing ovary tissue in their testes, while female fish have been found with sperm-producing nests in their ovaries instead of eggs. The chemicals also affect sexual differentiation in the womb, tilting the balance of male to female fish dramatically. In one study conducted downstream of Boulder’s wastewater treatment plant, researchers found a 10 to 90 ratio of male to female fish.”

An upset in the sex-ratio of breeding-age fish could contribute to massive population decline; affecting everything from the smaller fish and microbes they feed on (overpopulation), to pescavores like the American grizzly bear (starvation). So how do we head this problem off? What can we do? We’re not going to ask nearly half of all Americans to suddenly stop taking any and all environment-altering drugs—we need a practical alternative.

One such alternative might entail an update to our wastewater treatment plants. The World Health Organization (WHO) has identified a number of technologies and chemical processes (pdf) than can effectively remove up to 99% of pharmaceutical traces from wastewater—nanofiltration, reverse osmosis, ozonation, and advanced oxidation (pdf).

We can also modify how and where we treat wastewater. WHO suggests: “Preventive measures, such as policies promoting or regulations governing disposal practices at concentrated point sources (e.g. health-care and veterinary facilities), can reduce the amount of pharmaceutical waste entering water bodies. In addition, take-back programmes, guidance and enhanced consumer education will support efforts for the proper disposal of medicines and reduce the impact of pharmaceuticals entering our water sources.”

It’s worth noting that an excess of substances like fluoxetine in bodies of water isn’t all doom-and-gloom, however. A 2013 article in National Geographic cited a study conducted in Lake Erie which found that concentrations of dissolved Prozac was killing off E. coli-carrying bacteria.

But it’s nevertheless important to weigh the benefits of pharmaceutical intervention—not only in how they affect our personal bodies, but how they affect the environment once they leave them. Shrimp and birds, and other animals, are happiest when their habitat and planet is as undisturbed as possible. save the happy pills for making people happy.

Correction: A previous version of this post claimed that 48.9% of Americans used antidepressants at least once a month between 2009 and 2012. That figure refers to all prescription drugs. Nine percent of Americans reported using prescription antidepressants at least once a month during those years.