There are no ancient Tasker records for Buckinghamshire, but Thomas Tasker and his wife Hannah seem to have made up for things from the late 1700's onwards, with dozens of Tasker children and grandchildren in Preston Bissett. Preston Bissett is only a little village, midway between Buckingham and the Oxfordshire border, so maybe Thomas's parents were from one of the thriving North Oxfordshire Tasker tribes...?

A William Tasker, possibly part of the Preston Bissett clan, married Anne Busbey in Buckinghamshire in 1778, with the family having six children in all.  James - the 4th child, born in 1785 - was sent to Tasmania as a convict in 1820. He may have been married at the time, but was to marry again later in Australia (Thanks to Pat Beard for this information!).  
In total there are 121 Buckinghamshire Taskers on the IGI.