Feeding birds is fun — but it's important to make sure you're offering fresh food. Here's how to tell if your birdseed has expired or gone bad.
Does Birdseed Expire and How Can You Tell?
Published on Jun. 12, 2025
When it comes to human foods, we tend to defer to an expiration date to tell us what’s still good and what we need to throw away. Those dates stamped on packaging tell us when what we’ve bought is likely to stop tasting its best — or, for some perishable foods, when it might not be safe to consume. With that said, what about bird food? Does birdseed expire? Here’s what you should know about whether birdseed goes bad, and how you can best store seed to keep it fresh.
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Does Birdseed Have an Expiration Date?
The short answer? Yes, birdseed expires. The longer answer is that bird seeds tend to go stale or dry out, and while in many cases it likely wouldn’t harm the birds to put that seed in your feeders, the birds will probably avoid it. After all, we humans wouldn’t want to eat dried-out food — we can hardly blame the birds for feeling similarly. Ken Keffer, co-owner of the Wild Birds Unlimited Store in Bloomington, Indiana, explains: “Similarly to the seeds and nuts humans eat, bird food can go stale,” he says.
Store-bought suet, he says, usually has a best-by date on its packaging. Nyjer seed tends to go bad faster than others, Ken says, and it can often dry out quickly with improper storage. “This seed can quickly mold if it gets wet in storage or a feeder,” Ken says.
To determine whether your Nyjer seed is still good, he recommends crushing a few seeds between paper towels to determine whether there’s still oil in it. If there’s no oil coming from the crushed seeds, it’s best to dispose of it rather than offering it to the birds.
Offer Fresh Seed to Keep Birds Healthy
Ken also highlights that some types of seed can grow mold, and bacteria-laden or moldy seed can have adverse effects on birds’ health. “That can cause respiratory health problems in birds,” he says.
How Should I Store Birdseed?
To keep your birdseed fresh for as long as possible, you can take a few easy steps.
Ken says it’s a good idea to store seed in a metal container with a lid, and to keep seed in a cool, dry environment. In addition, make sure you’re not dumping new seed on top of, or mixing it with, old seed. “If you’re just piling new seed on top, the bottom layer can go bad, get stale, or even get buggy,” Ken says. Store suet in a cool, dry place.
To test if your seed poses a health risk, Ken recommends inspecting it for mold, obvious dampness, and foul odors. If the seed seems off, don’t risk it — toss it out.
Then, make sure to clean your bird feeders and storage containers, too. It’s also a good idea to make sure seed or suet in feeders isn’t accumulating mold, especially if you’ve had rainy or humid weather.
Should You Buy Birdseed in Bulk?
Ultimately, Ken says it’s a good idea to buy smaller amounts of birdseed at a time; a month’s worth in winter, and two weeks’ worth during hot weather.
Adding smaller amounts of seed to feeders can also help. “During especially hot or wet weather, only put out enough seed for a day or two,” Ken says. “You don’t have to fill your feeder up completely each time.”
RELATED:
- 12 Top Tips to Attract Birds to Your Feeders
- 3 Types of Feeders and Seed That Birds Love Best
- Bird Feeder Placement: Where and How to Hang a Bird Feeder
About the Expert
Ken Keffer is an award-winning environmental educator and author, and a past president of the Outdoor Writers Association of America. He has a degree in wildlife biology, and his career has been spent highlighting the importance of nature and encouraging people to explore the outdoors. He and his wife, Heather Ray, own a backyard bird feeding nature shop.
Sources
- Wild Birds Unlimited, “7 Top Tips for Storing Bird Food“
- Wild Birds Unlimited, “Keeping Bird Seed Fresh and Healthy for the Birds“
- Wild Birds Unlimited, “Why Aren’t My Birds Eating?“
