Bird nest fungi, also known as bird’s nest fungi, are a common type of fungus typically found growing on mulch or woody debris. Their distinct cup-shaped structure resembling a bird’s nest gives them their common name. Here’s a quick overview of bird nest fungi and their common names.
What do bird nest fungi look like?
Bird nest fungi have a very unique appearance that makes them easy to identify. They form small cup-shaped “nests” that are usually 1-3 cm wide. These nests grow in clusters, with each nest held up by a tiny stalk or stem. The inside of the cup is smooth and shaped like a bowl. Often the cups will have a layer of “eggs” – which are actually the fungus’s spores.
The nests are made up of fungal threads called hyphae that form the cup-like structures. The color can range from white to brown or gray. As the fungus matures, the eggs will rupture and release powdery olive-brown spores. Below the cups, there is usually whitish mycelium at the base.
Key Identifying Traits
- Grow in clusters
- Small cups on stems
- Smooth bowl-shaped nests
- Often have round spore capsules
- White mycelial fuzz at base
What are some common species?
There are over 10 genera and 50 species of bird’s nest fungi worldwide. Some of the most common include:
Splash Cups – Cyathus striatus
This is one of the most common and widely distributed species in North America. It grows on woody mulch and gets its name from the “splash” method it uses to disperse spores when hit by falling raindrops.
Tiny Nests – Crucibulum laeve
As the name suggests, this species has very small nests, around 2-5 mm wide. It is found on decaying leaves and twigs in forests in North America and Europe.
Hairy Nests – Crucibulum vulgare
Identifiable by the hairy exterior, this species has a cosmopolitan distribution. The hairs allow its spores to latch onto passing insects for dispersion.
Eyelash Cups – Cilia Cyathus
This species has distinctive “eyelash” like hairs inside the cups. It grows on mulch and forest debris in North America.
Species | Key Features | Location |
---|---|---|
Splash Cups | Smooth interior for splash dispersion | North America |
Tiny Nests | Very small nests | North America, Europe |
Hairy Nests | Exterior hairs | Cosmopolitan |
What do they grow on?
Bird nest fungi thrive on woody mulch, forest debris, and well-rotting logs. Specific substrates include:
Mulch
Bark and wood chip mulches, either in gardens or landscaping, are prime real estate for bird nest fungi. The nutrients and moisture are ideal for growth.
Dead Wood
Decaying stumps, fallen branches, and logs are also suitable environments, as they allow the fungus to degrade lignin and cellulose.
Living Trees
While less common, some species can grow as parasites on living tree trunks and roots.
Are bird nest fungi edible?
While not outright toxic, bird nest fungi are not recommended for consumption. The small, tough cups contain very little nutritional value. Additionally, some species have sharp hairs or calcium oxalate crystals that can irritate the mouth and throat if ingested.
Certain Cyathus species have reportedly been used in folk medicines in China and Nepal due to antioxidant and antimicrobial properties. However, they are not widely eaten as food. There are no known health benefits to eating bird nest fungi, and they are so fibrous as to be unpleasant to eat.
What ecological roles do bird nest fungi play?
As decomposers, bird nest fungi break down and recycle nutrients from dead plant material. Their ecological roles include:
Decomposition
Their mycelium secretes enzymes and acids that break down lignin and cellulose in wood. This makes nutrients available to other organisms.
Nutrient Cycling
They facilitate the transfer of carbon and nitrogen from dead organic matter back into the ecosystem for reuse.
Soil Health
Like other wood decay fungi, they help aerate soil and make soils more porous for improved drainage and oxygenation.
Biodiversity
As prey for small insects, worms, and other fauna, they contribute to forest food webs and support other life.
Are bird nest fungi dangerous?
Bird nest fungi are not dangerous or toxic to humans or plants. They help break down dead wood and do not damage living trees or spreads disease. Two minor cautions include:
Skin & Eye Irritation
The spines or hairs on some species can be irritating if handled extensively. Spores may cause eye irritation if there is direct contact.
Allergies
Rarely, some sensitive individuals may develop a minor allergic reaction if spore inhalation triggers an asthmatic response.
In most cases, bird nest fungi are harmless aside from minor nuisances. They do not spread any tree diseases and will not harm garden or landscape plants.
Should I remove bird nest fungi from my property?
Bird nest fungi rarely require control or removal. As decomposers, they are beneficial components of gardens, forest ecosystems, and mulched landscapes. Reasons to remove them include:
Aesthetics
The cups may look unattractive as they age and collapse. In maintained garden beds, they can be simply picked off and discarded.
Allergies
Those with spore-related allergies may want to eliminate extensive growths to reduce irritation.
Large Growths
Heavily mulched areas sometimes host expansive colonies. Removal helps reduce the overall load of fungal spores.
For most, though, removal is unnecessary. Raking or turning mulch periodically can help reduce growths. Letting the fungi run their course also allows the benefits of decomposition.
Key Facts
- Bird nest fungi have small, cup-shaped fruiting bodies that resemble eggs in a nest.
- They thrive on mulch, rotting wood, and forest debris.
- Splash cups, tiny nests, and hairy nests are common species.
- As decomposers, they recycle nutrients back into the ecosystem.
- Bird nest fungi are harmless and generally do not require removal.
Conclusion
With their unique cup-shaped fruiting bodies, bird nest fungi are fascinating and easily identifiable woodland finds. They play vital ecological roles as decomposers while posing no risks to garden plants or people. While not a food source, their unusual “nests” and splash or hairy dispersal make them a distinctive sight on forest floors and mulch beds across North America and beyond.