avicularium

An avicularium is a small, prehensile process found on many bryozoans. It resembles a bird's head with a movable mandible. These specialized zooids, often smaller than normal ones, have a proportionally larger operculum (a lid-like structure) with strong closing muscles, effectively acting as a jaw.12

Avicularia can be attached to normal zooids or, in some species like Bugula, they are mounted on short stalks and can move, closely resembling miniature bird heads, which gives them their name. While their exact function is not fully understood, they are thought to help keep the bryozoan colony clean by removing particles and preventing other organisms from attaching to its surface. The term "avicularian" describes something related to an avicularium.23