↑The names jay and magpie are somewhat interchangeable, and the actual evolutionary relationships are rather complex. For example, the Eurasian magpie seems more closely related to the Eurasian jay than to the Oriental Blue and Green magpies, whereas the Blue jay is not closely related to either.
Ericson, Per G. P.; Jansén, Anna-Lee; Johansson, Ulf S. & Ekman, Jan (2005): Inter-generic relationships of the crows, jays, magpies and allied groups (Aves: Corvidae) based on nucleotide sequence data. Journal of Avian Biology36: 222-234. PDF fulltext