News Animals

Bird nests made with a toxic fungus seem to fend off attacking ants

Ants who encounter horsehair fungus nests develop odd behaviors indicative of toxicity

A tiny bird with a black head and yellow-green body perches on a branch

Some birds, such as this yellow-olive flycatcher (or yellow-olive flatbill, Tolmomyias sulphurescens), use fungal fibers in their nests that appear to repel aggressive ants, a new study shows.

Salvador Poot Villanueva/iNaturalist Mexico (CC BY-NC)

By Richard Kemeny

When building a bird nest in ant territory, the best defense could be an offensive fungus.

Swollen-thorn acacia trees are aggressively defended by multiple species of ants.