The typical pattern is their home base will be in some southern state and then they'll travel north for pollinating. It happens along the east coast from Florida up to Maine and back. Some of it happens laterally west to east, so it's not true that every beekeeper is following the same pattern. The image of the bees after their hard work, which of course they don't, they kind of in.
Wally Thurman of North Carolina State University and PERC talks with EconTalk host Russ Roberts about the world of bees, beekeepers, and the market for pollination. Thurman describes how farmers hire beekeepers to pollinate their crops and how that market keeps improving crop yields and producing honey. Thurman then discusses how beekeepers have responded to Colony Collapse Disorder--a not fully understood phenomenon where colonies disband, dramatically reducing the number of bees. The discussion closes with the history of bee pollination as an example of a reciprocal externality and how Coase's insight helps understand how the pollination market works.