Suet is a popular food source offered to wild birds, especially in winter when natural foods are scarce. Suet provides birds with the high-fat content they need to maintain their energy levels in cold weather. However, many bird lovers have wondered if suet goes bad over time, and if birds will still eat suet cakes and other suet products after they have aged. In this article, we’ll examine the question “will birds eat old suet?” by looking at the shelf life of suet, signs of spoilage, and how to tell if the birds are actually eating the suet you provide. Quick answer: Birds will readily consume fresh suet. As suet ages, birds become more selective. If suet grows mold or smells rancid, birds will avoid it entirely. With proper storage, suet can remain usable for 1-2 months. Monitoring the suet and bird activity will help determine when it’s time to replace old suet cakes.
What is the Shelf Life of Suet?
Suet is the hard white fat found around the kidneys and loins of cattle and sheep. Beef suet has a higher melting point than other fats, which makes it appealing as winter bird food. The high fat content of suet offers birds up to twice as many calories per ounce compared to seeds.
Commercial bird suet is made by grinding suet into small bits or mixing it with other ingredients like peanut butter, cornmeal, oats, birdseed, and dehydrated fruit. The shelf life of suet depends primarily on the other ingredients used:
- Plain suet will keep for 2-3 months in the refrigerator or up to 6 months in the freezer.
- Suet combined with seeds and grains will keep for 1-2 months in the refrigerator or 2-3 months in the freezer.
- Suet enriched with nut butter or fruit will spoil most quickly, lasting for 2-4 weeks in the fridge or 1-2 months in the freezer.
Proper storage is key for maximizing the shelf life of suet products. Keeping suet cool and contained in an airtight bag blocks light, air exposure, and temperature fluctuations that cause oils to go rancid. Hardened suet lasts longer than soft suet logs or cakes. Freezing suet is ideal for long-term storage and will pause the spoilage clock.
Signs That Suet Has Gone Bad
As suet ages and starts to spoil, some clear signs will appear:
- Mold growth – Tiny spots of gray, green, black or white mold are an indication aged suet has become contaminated.
- Soft texture – Fresh suet maintains a hardened consistency. Suet with a mushy or slimy texture is past its prime.
- Strong rancid odor – Rancidity from oxidized fats causes suet to give off a distinct foul, waxy smell.
- Discoloration – Yellow or brown tinting of white suet shows oxidation of the fats.
If you detect any of these characteristics in your suet, it should be discarded and replaced with fresh suet for feeding birds. The increased moisture and mold growth can be unhealthy for the birds.
Will Birds Eat Spoiled Suet?
Birds have a strong sense of smell and taste. They are able to detect spoiled, rancid suet that is unfit to eat. Wild birds typically avoid consuming visibly moldy, smelly, or rotten suet. The notable exception is European Starlings, an invasive species with a knack for displacing native birds from feeders. Starlings have less discrimination and will eat questionable foods other birds won’t touch.
Healthy birds want high-quality, nutritious suet that gives them energy to maintain body heat and survive cold weather. As suet ages, the nutritional profile declines and potentially hazardous bacteria and fungi start to thrive. Birds can identify these changes and tend to shun old suet with obvious signs of spoilage.
However, birds may continue visiting the feeder and tasting aged suet to determine its freshness. Some crumbling of old suet is normal as birds repeatedly pluck at it. Crumbling alone doesn’t mean the suet has spoiled or the birds won’t eat it. Birds will try picking at the feeder for a day or two to find edible bits if the suet quality starts deteriorating but hasn’t completely spoiled. Over time, you’ll notice fewer birds interested in low-grade suet.
How to Tell if Birds Are Eating the Suet
To determine if birds will eat suet that’s been outside for an extended time, start by observing how much activity your suet feeder receives. Here are helpful signs birds are actively consuming the suet:
- Many birds visiting the feeder throughout the day
- Seeing birds clinging to the suet with their feet while pecking
- Fresh peck marks and indentations in the suet
- Rapid reduction in the size and shape of the suet cake or plug
You can also look below the feeder for evidence that birds are eating the suet:
- Suet crumbs collecting on the ground or snow below
- Outer suet paper rings on the ground after nuts are extracted
- A buildup of bird droppings underneath
On the other hand, signs that birds are not consuming the suet include:
- The suet looks untouched for multiple days
- No new peck marks visible in the suet
- Very little crumbling or debris under the feeder
- Few or no birds seen eating at the suet feeder
If the suet feeder goes unused for more than 2-3 days in cold weather, it’s likely the suet has lost appeal for the birds.
Replacing Old Suet
During winter, suet should be replaced every 2-4 weeks to ensure you’re providing high-quality bird food. Here are some tips for refreshing your suet supply:
- When putting out new suet, place it in a separate feeder from old cakes.
- Keep an eye out for birds preferring the new suet over old cakes.
- Remove and discard any unused suet that shows signs of mold, smells rancid, or is avoided by birds.
- Use more suet in winter when birds rely on it. Reduce suet in warmer months.
- Avoid leaving suet outside in heat which shortens shelf life.
Rotating fresh suet into your feeders will create a more sanitary and nutritious bird habitat. Discarding old suet also removes potential sources of bacteria and disease transmission.
Types of Suet That Last Longer
If you want to extend the usable life of suet, choose versions fortified with preservatives:
- Rendered suet – Commercially processed suet is rendered or cooked down to remove moisture that enables mold growth.
- No-melt suet dough – Special formulas resist melting in summer heat better than standard suet.
- Suet nuggets/pellets – Compacted suet bits limit air circulation and slow rancidity.
- Preservative-containing suet – Some brands use BHT, rosemary extract, or vitamin E to help maintain freshness.
You can also move your suet feeder to a shady area or add a shade canopy to help block heat exposure in warmer seasons. Freezing extra suet in winter for use later in the year extends shelf life dramatically.
Conclusion
Birds can detect when suet has spoiled and will avoid eating it. Fresh suet straight from the store is highly preferred and nutritional for birds. However, with proper storage, suet remains appealing to wild birds for 1-2 months and will continue being consumed. Monitor your suet feeder activity and discard suet once moldy, extremely hard, or smelly. Providing birds with the calories and energy from quality suet is important during cold winter months. With extra care and maintenance, you can successfully offer suet feeding that birds will relish all season long.
