Birds have been introduced to new regions by humans for centuries, for a wide variety of reasons, but recent years have seen a growing concern over the increasing numbers and variety of introduced birds becoming established in the UK. This book contains papers presented at a recent conference which examine some of the conservation issues surrounding bird species introduced to new areas, or within their natural ranges, both in the UK and elsewhere. Subjects covered include monitoring captive bird populations, escapes, colonisation and hybridisation, and case studies of the ruddy duck and Canada goose.