Bugula avicularia

Bugula avicularia is an erect bryozoan, common to British waters. The species forms branched, bushy, fan-shaped colonies which grow to between 2-3 cm in height. The branches of the colony are broad and flat, and when alive appear orange-brown in colour. The branches are arranged in a spiral formation around the main axis and divide dichotomously. Autozooids are rectangular or narrowing at the base.

Bugula avicularia mainly colonises other animals such as hydroids and other bryozoan species e.g. Flustra foliacea, which themselves may be attached to shells. Small modified zooids which resemble rootlets (Rhizoids) are used to attach to the colony to the substrate.

The species has been recorded from the intertidal zone, but is more common in subtidal waters down to approximately 100 m. It ranges from Shetland to Madeira, and can be found off all British coasts. It is also known to occur in the Mediterranean and the Red Sea, and potentially elsewhere, but is extensively confused with other species, especially B. stolonifera.