Bird migration perils cold temperatures on the wintering grounds kills thousands of birds, resulting in 30-90% population declines of migratory birds. For example, between 27000 and 62000 ducks, mostly tufted duck and common pochard, starved to death during a very cold winter in March 1986. The passing of Migratory Bird Treaty (US, 1916) and Migratory Birds Convention Act (Canada, 1917) made it illegal to kill or capture migratory birds. Even though migratory bird acts were passed at the beginning of the 19th century, many countries still have no laws or programs to protect migratory birds. International bird trade is a multibillion-dollar industry and
What Bird is That? kookaburra seated on and within a large red question mark. It contains 36 coloured plates of paintings of Australian birds by the author, as well as several black-and-white photographic plates of habitat. There were numerous reprints and revised editions in various formats produced well into the 1980s. The first edition was sponsored by the Gould League of Bird Lovers of New South Wales of which Cayley was a Council member. In return for its sponsorship, Cayley offered the Gould League four tenths of his 10% book royalty. However, initial sales were slow and in 1935 he sold his entire share