Extinct Birds 2nd edition

How do we know that a bird is extinct? This is a tricky question. Only today I heard on the news that a Bruijn’s bush‐turkey, not seen for 60 years and thought extinct, has turned up in New Guinea, being eaten by some hunters! And this sort of thing has happened before. Since the first edition of this book was published in 1987 several species seem to have been lost but two presumed extinct have been re‐discovered. Indeed, the book deals with some birds that I fervently hope are still hanging on in some remote outpost, birds such as the...