Zebra Finches are increasingly used as experimental animals, in particular in neuro-science research. There are presently no guidelines for the housing of these very active birds who are capable of exhibiting quite complex behaviour. The birds are often housed in monogamous pairs in small barren cages. In the present study it was investigated whether modest enrichment resulted in behavioural changes. The cages compared were small plywood box cages and cages double this size compared with similar size cages with additional perches, twigs as well as sand and water baths. An ethogram consisting of 17 different behavioural patterns was used. The behaviour of the birds was studied using a combination of alternating (15 sec) 1/0 and instantaneous sampling, 2 × 30 min per day during a continuous 4-week period. Vocalization, singing and exploratory behaviour was significantly increased in the enriched cages and flying was more frequent in the large enriched cage than in any of the other cages. The study demonstrated the usefulness of behavioural analyses to determine to what extent simple enrichment makes it possible for birds to exhibit a wider range of their natural behaviour.