Bird seed can go bad over time, just like any other food product. However, with proper storage, bird seed can last for many months past its “best by” date. The timeframe depends on the type of seed, storage conditions, and how it was processed.
When does bird seed expire?
Most bags of bird seed have a “best by” or expiration date printed on them, usually 6-12 months from the packaging date. This date indicates when the bird seed is estimated to be at peak freshness and nutritional quality. It does not necessarily mean the bird seed is unsafe to use after that date.
As long as the bird seed was stored properly, it should be fine to use for many months past its printed expiration date. Over time, bird seed will slowly lose some of its nutritional value as the oils in the seeds oxidize and the vitamins degrade. But it does not suddenly go rancid on the expiration date.
Signs that bird seed has spoiled and should be discarded include:
- Rancid smell
- Visible mold
- Clumping from moisture
- Many bug larvae or weevils in the bag
If the bird seed smells fresh and looks intact, it is likely still good to use from a safety standpoint. However, the nutritional quality degrades over time so it is ideal to use it within a year of the best by date.
Factors that affect shelf life
Several factors influence how long bird seed stays fresh and appetizing to birds after the package is opened:
Seed type
The various types of bird seed have different characteristics that affect shelf life:
Seed Type | Shelf Life |
---|---|
Black oil sunflower | 4-6 months past best by date |
Safflower | 6-12 months past best by date |
Nyjer/thistle | 6-12 months past best by date |
Millet | 6-12 months past best by date |
Mixed bird seed | Follow shortest expiry seed |
The oily seeds like sunflower tend to go rancid faster than drier seeds like safflower and millet. Nyjer thistle also stores very well. With mixed bird seed, the shelf life will be limited by the shortest expiry seed in the mix.
Storage method
To maximize shelf life, bird seed must be stored in a cool, dry spot in an airtight container. The ideal storage temperature is between 55-70°F. Here are some storage tips:
- Keep bird seed in original bag tightly rolled or in a sealable plastic/glass bin.
- Store away from direct sunlight and sources of heat or moisture.
- Use oldest bird seed first and add new seed on top.
- Discard clumpy or discolored seed.
Bird seed stored in damp areas like garages and sheds will deteriorate faster. The humidity causes the shells to soften and clump together. Warm spots also accelerate degradation of the oils. An airtight container prevents moisture and pests from infesting the seed.
Processing method
The way bird seed is processed and packaged impacts longevity:
- Raw vs roasted – Raw, untoasted seeds last longer. The roasting process causes the oils to start oxidizing.
- Whole vs hulled/chips – Seeds with hulls intact store better than hulled versions which are more prone to rancidity.
- Nitrogen flushed packaging – Some brands use nitrogen gas when sealing bags to displace oxygen and prolong freshness.
In general, raw whole seeds packaged with nitrogen flushing provide the longest shelf life compared to roasted, hulled seeds exposed to oxygen inside the bag.
How to tell if bird seed is spoiled
Here are some signs that your opened bag of bird seed has gone bad and needs to be discarded:
- Smell – Sniff the bird seed. Rancid seed smells stale, musty, or like vegetable oil.
- Appearance – Look for obvious mold, clumping, or webbing which indicates moisture damage.
- Pests – Check for tiny crawling bugs which is a sign of infestation.
- Taste – Take a small bite. Spoiled seed will taste bitter, metallic, or soapy.
If you suspect the bird seed is past its prime based on the expiry date but it still looks, smells, and tastes normal, do a freshness test. Place a small amount in a bowl of water. Fresh seed will sink while expired seed may float or partially sink.
Does spoiled bird seed make birds sick?
Eating spoiled bird seed is unlikely to make most birds seriously ill. Many birds naturally ingest moldy, rotten, and even toxic foods in the wild. Their digestive systems are equipped to handle it better than humans.
However, eating rancid bird seed over time may cause minor intestinal upset and nutritional deficiencies in birds. There have been isolated reports of birds becoming ill or dying after eating bird seed heavily infested with fungi and mycotoxins.
To be safe, it’s best to stick to the shelf life guidelines anddiscard old seed at the first signs of spoilage. Even if the bird seed won’t make your birds sick, the degraded nutrients and rancid taste means it’s no longer perfectly fit for consumption.
Can spoiled bird seed hurt other animals?
While most birds tolerate spoilage, snacks like chipmunks and squirrels are more sensitive. Rotten bird seed can potentially cause serious illness if eaten by:
- Rodents
- Dogs
- Cats
- Chickens
- Horses
Signs of illness may include weakness, vomiting, diarrhea, tremors, and hypothermia. Never intentionally feed other pets or wildlife spoiled bird seed.
Even just having access to the storage area could harm them. Make sure dogs and rodents cannot get into the garbage bins containing old bird seed. Many dogs love munching on bird food and can get into deadly trouble if they eat moldy seed.
Does microwaving revive old bird seed?
Microwaving is sometimes suggested as a way to extend the life of aging bird seed. The theory is that the heat will kill bacteria and mold spores, stopping further deterioration. However, this is not an effective solution.
The microwave does not heat food evenly. It may kill some surface microbes but leave fungus buried inside untouched. Oil rancidity and nutritional loss cannot be reversed. Microwaving bird food can even create hot spots that burn seed hulls or further degrade nutrients.
At best, microwaving old seed provides no major benefits. At worst, it creates false confidence in spoiled seed while leaving potential toxins. It’s safer to simply discard bird seed at the first significant signs of aging.
Can old bird seed be composted?
Small amounts of discarded bird seed can be added to compost piles. It provides carbon and nitrogen to feed microbial growth. However, composting large quantities of bird seed can pose some problems:
- May attract pests like rodents to the compost
- Adds a lot of volume without much nutritional benefit
- Can clump into a thick sludge as it rots
- Moldy seed may release mycotoxins
To compost bird seed safely:
- Mix in thin layers with other compost, don’t pile thickly.
- Turn and aerate the heap frequently to prevent anaerobic rotting.
- Avoid adding seed with visible mold or heavy insect infestation.
Because of the potential drawbacks, many municipalities recommend disposing of large amounts of spoiled bird seed in the regular trash rather than compost. Small amounts can be beneficial but too much risks creating an imbalance.
Conclusion
With proper dry, cool storage in an airtight container, most types of bird seed will stay fresh and tasty for birds for 4-12 months past the best by date. Discard at the first signs of moisture, clumping, rancid odor, bugs, or mold. Spoiled seed won’t seriously harm birds but degrades nutritional quality over time. Don’t feed spoiled seed to pets or compost large amounts. Following these tips will help bird seed stay optimally fresh.