Hummingbirds are amazing little creatures that have captured the fascination of people for centuries. Their ability to hover mid-air and fly backwards sets them apart from other birds. These tiny birds have extremely high metabolisms and must consume up to half their weight in nectar each day to survive. They get most of their nutrients from flower nectar and tree sap. To supplement their high-energy needs, hummingbirds also eat small insects and spiders. The primary component of a hummingbird’s diet is sugar in the form of nectar. This is why humans often put out hummingbird feeders with sugar water to attract these special birds. But what happens if the sugar water becomes contaminated with mold? Let’s take a closer look.
What is Mold?
Mold is a type of microscopic fungi that grows in filaments and spreads through the dispersal of spores. There are thousands of known species of mold. Mold spores are present everywhere – floating in the air, on plants, in the soil. These spores only grow when they land on a wet surface that contains organic material. Ideal environments for mold include damp areas like compost piles, wet leaves, rotting wood, bathroom tiles, drywall, carpet, or even nectar feeders. Grayish-white or greenish-black spots are usually the first sign of mold growth. Mold releases countless spores as part of its reproduction cycle. Exposure to elevated mold spores can cause allergic reactions.
Some common molds that grow on food or liquids include:
- Penicillium – blue or green mold on old bread, cheese, fruit
- Cladosporium – olive-green or black spots on strawberries, tomatoes, cucumbers
- Aspergillus – powdery gray or brown mold on nuts, onions, spices
- Mucor – grayish fuzzy mold on packaged food, jam, canned goods
Let’s take a closer look at how mold could end up growing in hummingbird nectar feeders.
How Does Mold Get in Hummingbird Feeders?
There are a couple ways that mold spores can contaminate the sugar water in hummingbird feeders:
- Airborne Mold Spores – Mold spores float unseen in the air all around us. When you are filling or refilling a hummingbird feeder, these spores can land in the sugar water. With the right conditions, they germinate and quickly multiply.
- Contaminated Equipment – If any equipment used to make sugar nectar has mold, like stored bags of sugar or measuring cups, the spores transfer to the feeder. Washing equipment in hot, soapy water can help kill spores.
- Spoiled Nectar – Any leftover sugar water sitting in the feeder from previous fillings can spoil and harbor mold growth. Change the nectar frequently.
- Dirty Feeders – Buildup of dirt, dust, insects, and residue can introduce mold spores. Regular cleaning is essential.
- Humid Environments – Warm, humid, rainy environments encourage fast mold growth. Keep feeders out of the rain and empty when not in use.
Even if you thoroughly clean and sterilize feeders, airborne spores can still contaminate the nectar. Let’s look at what types of mold grow in hummingbird feeders and the dangers they pose.
Common Mold in Hummingbird Feeders
Two of the most common molds found growing in hummingbird nectar solutions are Aspergillus and Penicillium. The preferred food source for these molds is the sugar content of the nectar.
Aspergillus
This mold can appear gray, brown, black, yellow, or green. It has a dusty or powdery texture and gives off a musty odor. It thrives in warm, damp environments with little air circulation. Aspergillus releases toxins called mycotoxins that can cause illness in birds and humans if ingested.
Penicillium
This mold is identified by blue, gray, green patches with a soft velvety texture. It grows in cooler, drier settings. Penicillium also releases mycotoxins and can be dangerous if consumed.
Both Aspergillus and Penicillium reproduce by releasing millions of microscopic spores into the air. Even dead mold continues shedding spores. So if a hummingbird drinks nectar containing these molds, what effect will it have?
Effects of Moldy Nectar on Hummingbirds
Unfortunately, when a hummingbird ingests sugar water contaminated with mold, it puts the bird’s health at serious risk. Here are some potential consequences:
- Digestive Issues – Ingesting mold spores can irritate the stomach and intestines, causing discomfort, vomiting, diarrhea.
- Immune Problems – Mycotoxins suppress the immune system, making the bird vulnerable to disease.
- Respiratory Distress – Mold spores inhaled into lungs can cause wheezing, labored breathing.
- Organ Damage – Toxins from mold can damage organs like the liver and kidneys.
- Fungal Infections – Mold can spread internally and externally, resulting in candidiasis, aspergillosis.
- Death – If the mold load is very high, it can be fatal. Sick birds become easy targets for predators.
The impacts really depend on the type of mold, the amount ingested, and the overall health of the bird. Young hummingbirds seem to be most at risk. Let’s look at some signs of mold sickness in hummingbirds.
Signs of Sickness from Mold
Watch for these physical indicators that a hummingbird may be suffering ill effects from contaminated nectar:
- Loss of appetite
- Lethargy
- Ruffled feathers
- Disinterest in flying or feeding
- Difficulty breathing
- Sudden weight loss
- Green diarrhea
- Eye or nasal discharge
- Loss of directional control
- Tremors or seizures
The sooner mold poisoning is identified, the better the chances are for recovery with treatment. Let’s look at some ways we can help prevent mold in the first place.
Preventing Moldy Nectar
To minimize the risk of mold growth in homemade nectar solutions, here are some tips:
- Use sterile equipment – Disinfect feeders, bottles, scoops with a 10% bleach solution. Rinse thoroughly.
- Use fresh ingredients – Unopened bags of white sugar work better than brown sugar, honey, or artificial sweeteners.
- Boil the mixture – Heating the water kills mold spores before filling feeders. Let cool before pouring into feeders.
- Add vinegar – A few drops of apple cider vinegar per quart helps inhibit mold growth.
- Avoid overdiluting – Follow a strict 1:4 sugar-to-water ratio. Weak solutions mold faster.
- Fill feeders halfway – Less nectar means less chance for contamination.
- Change nectar regularly – Every 2-3 days in warm weather; 5 days in cooler temps.
- Clean feeders thoroughly – Use a bottle brush to scrub insides. Rinse in hot water.
- Dry feeders completely – Let air dry upside down before refilling.
- Avoid moisture – Keep feeders sheltered from rain. Take down if wet.
- Discourage bees – Use bee guards. Bees can spread mold between flowers and feeders.
Following these tips religiously can help provide hummingbirds with a safe, mold-free nectar source. But what if despite your best efforts, you end up with moldy nectar?
What to Do With Moldy Nectar
If you discover mold growing in your hummingbird feeder, here are the proper steps:
- Take down the feeder immediately – Prevent sickening the birds
- Discard the old nectar – Dump out liquid, don’t rinse remains down the drain
- Scrub the feeder – Use hot water, soap, vinegar, bottle brush
- Sterilize with bleach solution – 1 part bleach, 9 parts water. Saturate and let sit 10 min.
- Rinse thoroughly – No bleach residue should remain
- Air dry feeder – Upside down in the sun; pat dry with cloth
- Make fresh nectar – 1:4 ratio sugar:boiled water; add vinegar
- Refill feeder halfway – Prevent waste of unused nectar
- Monitor birds closely – Watch for signs of sickness
- Change nectar every 2-3 days – Frequent changing deters recurring mold
With this process, your feeder should be mold-free and safe for hummingbirds again. But is there anything you can do for birds already sickened by moldy nectar?
Treating Sick Birds
If you spot any hummingbirds in your yard appearing ill or lethargic, remove nectar feeders immediately. Then:
- Capture the sick birds – Use a butterfly net or small box. Handle carefully.
- Place in a pet carrier – Dark, quiet, well-ventilated.
- Provide fresh water – Give birds clean water to drink.
- Contact a wildlife rehabilitator – Get professional medical treatment.
- Avoid antibiotics – Can kill healthy gut bacteria needed to fight mold.
- Administer antifungals – Prescribed to treat systemic fungal infections.
- Treat symptoms – May include IV fluids, nutritional support.
- Release birds once recovered – Usually 1-2 weeks of rehab.
With quick intervention, sick hummingbirds can often recover fully. Some key points to remember:
- Act quickly at first signs of illness
- Always provide clean nectar and clean feeders
- Consult an avian vet for proper diagnosis/treatment
- Support wildlife rehabbers in your area
- Educate others about the dangers of moldy nectar
Let’s recap the key points in this article:
Conclusion
Hummingbirds have unique nutritional needs because of their super-charged metabolisms. They rely heavily on the sugar in nectar to provide sufficient energy. While feeders allow us to observe these special birds up close, they also pose risks if they become contaminated with mold. Warm, humid conditions encourage mold growth in sugar solutions. Two common culprits are Aspergillus and Penicillium molds. Consuming the toxins these molds release can cause respiratory issues, organ damage, infections, and even death in hummingbirds. By preparing fresh nectar properly, changing it frequently, and cleaning feeders thoroughly, we can reduce the chance of mold. But if contamination does occur, it is crucial to remove moldy liquid right away and rehabilitate any sick birds. With extra care and vigilance, we can make sure our backyard feeders provide only healthy nourishment for hummingbirds to thrive. These tiny feathered fliers deserve our best efforts to keep them safe.