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Common bird’s nest fungus (Crucibulum laeve)

Clinging to twigs and branches like tiny birds’ nests, each common bird’s nest fungus looks like a clutch of white eggs. Using the power of raindrops to fling spore sacks into the air, it wraps a short cord around any twig it connects with and waits for the right conditions to spore.

This fungus resembles tiny birds' nests.

Credit: Hakan Soderholm / Alamy Stock Photo

Quick facts

Common name: common bird’s nest

Scientific name: Crucibulum laeve

Family: Nidulariaceae

Fruiting season: July to October

Habitat: decaying wood in woodland

What does common bird's nest fungus look like?

Common bird’s nest is a distinctive woodland fungus that looks like a bird’s nest filled with small, white ‘eggs’ in the bottom.

Cap: the tiny cups, 4–10mm across, are at first covered by a velvety, cinnamon-yellow membrane called an ‘epiphragm’. The membrane eventually ruptures, revealing a clutch of flattened white ‘eggs’ called periodoles, which contain the spores. Each periodole is attached to the cup by a thin cord called a ‘funiculus’.

Spores: the periodoles containing the spores use the energy of raindrops to splash out of the nest, up to four feet away. The sticky end of the minute cord which attached them to the cup can come into contact with a twig and rapidly wind around it. Typically, there are five to eight periodoles in each nest, each 1.5mm in diameter. The spores are oval-shaped and the spore mass is white.

Not to be confused with: other bird’s nest fungi, such as the fluted bird’s nest fungus (Cyathus striatus) which has ribbed nest walls; and bird’s nest fungus (Cyathus olla), which is larger.

Credit: DP Wildlife Fungi / Alamy Stock Photo

Where to find common bird's nest fungus

Common bird's nest fungi are found throughout the UK. Look out for them in clusters on decaying wood, twigs and bark fragments in all types of woodland, particularly where dark and damp. Also found in parks and gardens on wood chips and bark mulches. However, they are so small, they are easy to overlook.

Value to wildlife

They are nibbled by small creatures and even cows and horses, which helps to disperse the spores in the animals’ dung.

Did you know?

In the eighteenth century, before we knew how fungi reproduce, the ‘eggs’ were thought to be fungi seeds.

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