I'd be willing to bet money that all the survey companies have already hired all of their pilots for the season. With these hard times in aviation and little to no movement many pilots are doing 2-3 seasons of survey work before being able to move on to better things.

Bradslvr is right on. There are many different vendors and they all have different pay scales for the same exact job. I have done this work in the past and am going back to doing it again this season. Beats being a CFI if you can handle being on the road for so long. It's not for everyone though, you'd better be good at flying a plane with no autopilot.