I recently moved to a new server. Now I see a huge drop in kilobytes downloaded per day. Pages crawled per day stays the same. Can this be caused by the new server ? or is there another reason. (maybe Panda or Penguin ?)
If it's the same site, I'm going to guess that you minified js/css files or enabled caching on the new server. Caching alone will significantly reduce bandwidth - you can confirm by looking for 304 status codes in your web server log file.