Real Dictionary

magpie
countable noun: A magpie is a large black and white bird with a long tail.
countable noun: If you describe someone as a magpie, you mean that they like collecting and keeping things, often things that have little value.

magpie in American English
any of several jaylike corvids, passerine birds characterized by black-and-white coloring, a long, tapering tail, and a habit of noisy chattering
noun: either of two corvine birds, Pica pica (black-billed magpie), of Eurasia and North America, or P. nuttalli (yellow-billed magpie), of California, having long, graduated tails, black-and-white plumage, and noisy, mischievous habits

magpie in British English
noun: any of various passerine birds of the genus Pica, esp P. pica, having a black-and-white plumage, long tail, and a chattering call: family Corvidae (crows, etc)