Hummingbird Diseases: From Pathogens to Prevention

Every minute of every day a hummingbird is susceptible to diseases and unknown pathogens. Have you ever encountered a hummingbird with an enlarged growth on their beak and wondered what hardships it has endured? Ever speculate if these growths are from a battle wound or from unsanitary conditions?

Having been curious about a hummingbird’s story and their personal journey in life, I researched and uncovered not only eye-opening but educational information about hummingbird diseases and how to prevent them. Can they be transferred to humans and is there anything I can do to help prevent diseases from spreading?

Can hummingbirds and humans transmit diseases to each other?

Hummingbirds are just like any other wild animal and can transfer diseases easily from one hummingbird to another. Humans can not transfer disease to hummingbirds and close contact with hummingbirds does not spread their diseases to humans with the exception of Salmonellosis (salmonella).

Hummingbirds are wild animals and have been documented to carry a variety of diseases such as:

  • Candidiasis (fungal tongue infection)
  • Avian poxvirus (tumor growths on beaks)
  • Aspergillosis (type of mold/fungus)
  • Salmonellosis (bacterial)

Transference of diseases can be linked to improper, infrequently cleaned or overcrowded hummingbird feeders.

Studies performed in California by the San Diego Zoo spanning from 1996 to 2016 examined wild hummingbirds that had died due to infectious diseases or trauma. Their findings show the hummingbird organs that were most affected were the lungs and the liver.

With that being said, continue to protect yourself and treat hummingbirds like you would any other wild animal. Hummingbirds that are infected or dead should always be handled using disposable gloves.

Below are the four common diseases spread by hummingbirds.


Candidiasis is a fungal tongue infection that causes an imbalance of bacteria in the hummingbird’s digestive tract and is spread through contaminated water sources or feeding grounds.

Identifying the correct and safe ingredients to use while making homemade hummingbird nectar will give your hummingbird friends a fighting chance in avoiding sickness. A hummingbird’s feeding station that is unclean becomes an easy target for diseases to multiply and spread.

Read my article on Forget Commercial Hummingbird Food, Try Making Homemade Nectar

One expert describes adding honey to homemade nectar (a danger to hummingbirds) as a main contributor to hummingbirds catching Candidiasis. Honey, water and heat create a perfect fermentation of bacteria. Old hummingbird nectar, even if using table sugar, will also cause yeast and bacteria to grow and make the perfect breeding grounds for candidiasis.

Hummingbirds catch candidiasis through poor hygiene or by consuming too much sugar or carbohydrates. Abide by the 1-4 ratio of sugar to water to refrain from hummingbird nectar that is overly sweet.

Candidiasis makes it extremely difficult for hummingbirds to consume and digest food causing them to become malnourished,eventually starving to death.

Fungal infections can be treated with medications by a professional therefore if you suspect a fungal infection, immediately transport them for treatment.

Avian Poxvirus

Avian poxvirus is a tumor growth on a hummingbird’s beak. It is transmitted from contact with hummingbirds that are already infected and from touching contaminated surfaces such as perches, feeders and exposed water sources. It can also be spread from contact with mosquitoes.

The Avian poxvirus tumors can grow on their legs, feet, eyelids, beaks and in their mouths. Enlarged sores in their mouth make it difficult for the hummingbird to locate or consume food. Mortality can be the ultimate end for a hummingbird when the situation cannot be cured or remedied.

There is a greater risk of spreading this disease at a commonly used and frequently visited hummingbird feeder that is not regularly cleaned and maintained.

Cutaneous pox (or dry pox) is the most common form of the Avian poxvirus. It is contagious between birds and can be fatal. Thankfully, humans are not affected by the cutaneous pox.

There are multiple variations of the Avian poxvirus that affect each hummingbird species differently. The virus can last from 7 to 14 days in the body. The good news is most hummingbirds who contract the virus will recuperate.


Aspergillosis is a common mold and a type of fungus that infects unclean hummingbird feeders. The spores that are produced become airborne, are inhaled, and can spread to the gastrointestinal tract where they wreak havoc on a hummingbirds’ digestive system.

Hummingbirds will experience a slow death if they become incapable of eating, digesting or absorbing any nutrition. Common symptoms include nasal discharge, weight loss and diarrhea.

Aspergillosis grows and thrives in moist climates where there is poor ventilation. The inability of the surrounding environment to “dry out” creates the perfect breeding ground for growth. This fungal infection also affects the lungs of hummingbirds who are immunocompromised. Pneumonia and bronchitis thrive when spores from the fungus are inhaled and settle in their lungs.

Hummingbirds with poor health will mask their illness and will continue to eat at feeding stations until they perish. Hence, this dormant disease is easily spreadable.


Salmonellosis or Salmonella is a common bacteria that affects most hummingbirds by infecting and contaminating food or water sources. This bacteria will affect the intestinal tract of the hummingbird, once again giving them the inability to absorb nutrients from their food sources.

Common symptoms from this bacteria include diarrhea, ruffled feathers and lethargy. Once symptoms occur hummingbirds have 1 to 3 days left to live. Rapid growth is transferred and spread by overcrowded feeding stations that have not been properly cleaned regularly.

Experts say Salmonella is the only disease that can be spread to humans when handling sick or dead birds. Therefore it is important to protect yourself by wearing gloves and washing your hands after touching an infected hummingbird. Humans cannot get sick by touching healthy hummingbirds.

Other Hummingbird Pathogens

Various types of diseases have been known to infect hummingbirds such as trichomoniasis, haemoproteus parasites, intestinal adenovirus and bacterial septicemia.

Trichomoniasis (trik-oh-moh-ny-uh-sis) is a virus caused by parasites that infect the digestive and urinary tract system. These parasites cause sores in the mouth and throat prohibiting the hummingbird from swallowing. This in turn slowly starves the hummingbird to its death. The disease is spread by hummingbirds consuming contaminated food.

Haemoproteus parasites (hey-moh-proh-teh-us) are transmitted and spread through blood sucking insects. This includes mosquitoes, biting midges and louse flies. These insects infect the hummingbirds similar to malaria infecting humans.

According to a National Institutes of Health study, Haemoproteus blood sucking parasites may be viewed as hummingbird specialists.
See the NIH research article here…

Intestinal adenovirus (ah-deh-no-vi-rus) is more like the common cold but specifically causes infections in the respiratory and intestinal tract. When intestinal damage occurs it affects digestion. Hummingbirds can become malnourished and die due to starvation.

Bacterial septicemia (sep-te-see-mee-uh) is caused by bacteria in the bloodstream leading to blood poisoning. This toxic blood is quickly transferred throughout the body causing damage to the hummingbirds organs and can be fatal if not treated.

Some main causes of blood infections are from:

  • Urinary tract infection (UTI)
  • Lung infections
  • Digestive issues
  • Head trauma and physical injuries

Insect Invasions in a Hummingbird Nest

Hummingbird nests can provide the perfect home for diseases and pathogens to accumulate and cultivate. Some common types of bugs that invade nests are booklice, carpet beetles, cloth moths and spider beetles.

Booklice are very small bugs that have no wings and feed on fungi. They do not bite or transfer diseases but can be irritating to a hummingbird in high cultivating masses.

Carpet beetles gather inside the breeding grounds and consume anything from fungi to feathers and natural fibers. Their voracious appetite for anything in the nest, including the nest, is destructive and damaging to the hummingbird nest.

Cloth moths eat natural fibers such as wool and silk. A bird’s nest is the perfect breeding ground for rapid procreation of these pests. When hummingbird nests are located near inlet vents and air infiltrations in a home there is the opportunity to find these invasive moths in closets eating clothing materials.

Spider beetles look like small spiders or ticks and feed off of bird excrement. These beetles increase in population when freshly displayed baby hummingbird squirts are seen in and around the base of the nest.

Susceptible to Mites and Lice

Have you ever spotted a hummingbird on a high perch preening themselves and witnessed their back leg scratch their neck and head similar to what a family pet dog would do when he has fleas? You can bet these hummingbirds are suffering from the same uncomfortable experiences and do not even have a kind owner to watch over and take care of them.

Hummingbirds are also susceptible to hosting mites and lice. They can become infested with feather mites or blood-sucking mites. One type of mite enjoys drinking blood, while the other mite likes to catch a free ride to their next destination on the feathers of the back of a moving hummingbird.

Blood sucking mites can cause anemia and death especially to young babies when they attack the host in large numbers.

Feather mites attack the heads of hummingbirds where it is difficult for them to reach when bathing or preening. These parasites are able to destroy the head feathers of hummingbirds exposing their skin to the sun. If a hummingbird is successful in getting rid of the mites their head feathers will grow back in two or three weeks.

Research has also found that nearly 60% of feather mites are found in tail flight feathers of Anna hummingbirds. A male Anna hummingbird has 24% more mites on their tail than a female Anna hummingbird.

The conducted analysis done by researchers shows individual tail feathers have more mites on the outer perimeter edges rather than mites found nestled in the inside of the tail feathers.

Contracting head mites or tail mites is extremely devastating to a hummingbird. Imagine being bald and your raw skin is exposed to the blistering hot sun making you look unattractive, undesirable and sickly. Nobody wishes that upon their worst enemy.

Disposing of a Dead Hummingbird

When disposing of the remains of a deceased hummingbird, it is strongly recommended to wear gloves. Most often the feathers of a dead hummingbird carry more parasites, bacteria and viruses than a living hummingbird. Use disposable gloves or a plastic bag when safely discarding the body of a dead hummingbird. The two most common options of removing a dead hummingbird from your yard is to bury it in the ground for mother nature or to put it in the trash.

If you decide to discard the hummingbird in the trash, the best thing to do is to place and wrap the hummingbird in a plastic bag. Burying a hummingbird responsibly requires digging their resting place at least 1 foot deep in the ground. Since the body is small it will decompose naturally and feed nutrients into the soil providing a healthy base for plant life to grow.

On the other hand, if you decide to bury the hummingbird there is a possibility their resting site could be disturbed. By placing the body in the trash even though it seems inhumane, will eliminate potential scavengers looking for a meal or aiding in future contamination.

Either way is acceptable, it all depends on your driven outcome.

Feeder Maintenance and Disease Prevention

Preventing the spread of diseases is significantly beneficial for hummingbirds, humans and the overall health of our ecosystem. Here are a few guidelines to follow when preventing diseases from spreading around your hummingbird feeders.

  • Clean your hummingbird feeder frequently
  • Purchase feeders that have a wider mouth for easy cleaning
  • Rotate and spread out your feeding stations
  • Eliminate pesticides

Frequently Clean Feeders

Clean your hummingbird feeder at least once a week when using glass feeders. Frequent cleanings eliminate mold and mildew from building in your feeder. More regular feeder cleanings are necessary during warm weather since conditions are easier for bacteria to grow.

Plastic feeders can cause homemade nectar to ferment more quickly than glass feeders during the warm weather season. If you use a plastic feeder, frequently change the nectar.

To disinfect a feeder that is covered by black mold, soak and scrub it using a diluted solution of hydrogen peroxide or white vinegar. The diluted ratio is 2:1. Two parts water to 1 part hydrogen peroxide or white vinegar. Do not use warm soapy water to clean your hummingbird feeders. The soapy residue left behind which is not beneficial to the hummingbird.

Use a bottle brush to reach and clean difficult places. Completing this step eliminates black mold that builds up in or around the feeder preventing contamination.

Mold and fungus can also easily build up from using the standard size yellow bee guards. These guards are added to the flower or opening that is attached to the feeder to prevent bees accessing the nectar. Remove them and clean separately.

Let the feeder completely dry before refilling.

Wide Feeder Mouth

Purchase feeders that have a wide mouth and make sure your bottle brush fits the mouth of the feeder for proper cleaning. If one of your feeders has too much black mold built up and becomes too difficult to clean, throw your feeder away and buy a new one. As a hummingbird enthusiast I am sure you will agree that the health of your hummingbird is more important than trying to save a few dollars.

As a rule of thumb, even if there are no signs of diseases being transferred from hummingbird to hummingbird, continue to regularly clean your feeders.

Rotate and Spread out Hummingbird Feeding Station

Regularly visited feeding stations require fresh hummingbird nectar and clean spaces. To accomplish this, rotate and spread out your feeding stations to avoid contamination from a single sick hummingbird infecting the rest of the group.

Crowded and unkempt feeding stations increase the chances of spreading diseases. Allowing the hummingbirds to have plenty of space and room to feed will reduce the spread of diseases.

Remove Pesticides

Remove and eliminate any harmful pesticides in your backyard. Any chemical agent that is used to cure or protect a plant from insects or diseases can interfere with a hummingbird’s daily life and unintentionally harm them.

If you have a pest or mold problem in your landscaping area and need stronger agents there are some safe products on the market that are available such as Neem oil which is considered to be organic. Neem oil is non toxic to birds, mammals, bees and plants.

Products that use Neem oil are Garden Safe Fungicide3 (a 3 in 1 product) or concentrated 70 percent Neem oil products. When using these products make sure to spray at night while the hummingbirds are sleeping. When the product is dry it does not affect the hummingbirds.

If you see a distressed hummingbird that is sick or injured attend to their needs quickly and provide them with assistance to prevent further infections and diseases from spreading. If a hummingbird is suffering and does not get the proper medical attention they need in a timely manner they will most likely die.The sooner the hummingbird receives help the better the chance it will respond positively to treatment and have a more successful rate of recovery.

For further assistance, contact your local wildlife veterinarian, rehabilitator or a hummingbird rescue center.


Hummingbirds are vulnerable to catching diseases and dying from exposure to dirty and contaminated feeding stations and water sources, other affected hummingbirds, contacting nest parasites and not sustaining enough food to function properly due to their sickness.

The best place diseases can easily multiply and spread occurs at overcrowded feeding stations. Keep your area clean and feeders separately distanced apart to prevent diseases from spreading.

Wild animals carry diseases and it is recommended, not mandatory to use gloves when handling them. A person cannot get an infectious disease from physically touching a hummingbird, except for a hummingbird infected with Salmonellosis. Thoroughly wash your hands with warm soap and water after handling any wild animal.

When disposing of a dead hummingbird it is always advantageous to protect yourself by wearing disposable gloves and wash your hands afterwards.

Taking a fast action approach when encountering a distressed hummingbird can lead to positively saving a hummingbird’s life while taking the necessary precautions to protect yourself.

Happy Hummingbird Watching!

Backyard Visitors

Hi Everyone! I have always loved our backyard and have been fascinated with all the wildlife living there. I am especially amazed by the skill, strength, and beauty of hummingbirds. I hope this article answered your questions.

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