Moldy Food

Also known as: moldy bread, moldy feed, spoiled food, rotten scraps, compost scraps

Danger (Avoid)

Moldy food is one of the most underestimated killers at bird feeders. That seed mix that's been sitting in the rain for two weeks, the bread that went green on the bird table, the fat ball that's turned rancid in the summer heat — they're all breeding grounds for Aspergillus mold, which produces aflatoxins that destroy a bird's liver. Stale, damp, forgotten food in feeders kills more garden birds than most people realize.

Quantity

Aflatoxin poisoning is cumulative. A bird doesn't need to eat a large amount of visibly moldy food at once — regular exposure to low levels of mold on slightly stale seed causes slow liver damage over weeks and months. By the time the bird shows symptoms, the liver is already badly compromised.

Notes

This is almost entirely a feeder hygiene problem. Tube feeders with damp seed clumped at the bottom, bird tables with old food piling up, fat balls left out in humid weather, and ground feeding trays that never get cleaned are all mold factories. The responsibility falls on whoever maintains the feeder. If you put food out for birds, you're also signing up to keep that feeding station clean.

Negative Signs

* Labored breathing — open-beak panting, wheezing, tail bobbing
* Weight loss — a bird that looks thin despite visiting the feeder regularly
* Fluffed feathers and lethargy
* Discharge from the nostrils or eyes
* A bird that sits at the feeder but doesn't eat
* Multiple sick birds appearing at the same feeder (sign of disease spread)

FAQ

Q: How often should I clean my bird feeders?
A: At minimum, once a week with hot soapy water. Once a month, do a deeper clean with a 10% bleach solution (one part bleach, nine parts water), rinse thoroughly, and let the feeder dry completely before refilling. In wet weather, clean more often.

Q: The seed in my feeder looks fine — no visible mold. Is it still okay?
A: Mold can be present before it's visible. If the seed has been in a damp feeder for more than a few days, or if it smells musty, replace it. Clumped-together seed is a strong sign of moisture and mold growth.

Alternatives

The solution isn't different food — it's fresh food and clean feeders. Put out only as much food as the birds will eat in a day or two. Clean feeders weekly with hot soapy water (or a 10% bleach solution monthly). Rotate feeding spots so droppings and old food don't accumulate. In wet weather, use feeders with good drainage and rain covers.

Risks & Disclaimer

If you notice multiple sick birds at your feeder, take the feeder down immediately and clean it thoroughly with a 10% bleach solution. Let it dry completely before refilling with fresh food. Contact your local wildlife organization — outbreaks of aspergillosis and other feeder-spread diseases should be reported.