Hummingbird is a new algorithm update that is intended to help Google better work with sentence based questions as opposed to keyword queries. At this point there is little information on how this algorithm works or what exactly it will do.
More information is coming abut how what this new algorithm does. In this FAQ they explain that the change focuses mainly on how Google processes queries rather then how it judges and ranks sites. While this may shift rankings, it’s focus is on answering the question in context rather than matching keyword terms. The important thing for an SEO if to keep creating high quality content that answers questions and adds value.