This Detailed Review Paper (DRP) is intended to provide the current state-of-the-knowledge in the area of avian endocrinology, with a particular focus on the evaluation of possible endocrine disruption in birds in two-generation tests. The content of this review is intended to describe test methods, already existing or in development, that could be used in testing chemicals for their potential to interact with the endocrine system of birds and likely to create population damage. However, the methods described do not strictly focus on endocrine disruption in terms of endpoints measured, but rather also on reproductive and developmental performance of individuals exposed. It is planned that test methods under development or enhanced, will be validated to establish their relevance (i.e. whether the test is meaningful and useful for the intended purpose) and their reliability (i.e. reproducibility of test results over time within and among laboratories).