A motorcyclist suffered serious head injuries after hitting a deer on the A413.
The 51-year-old biker was travelling through Wendover Dean towards Great Missenden when he collided with the animal and was thrown off his vehicle.
As well as serious head injuries he sustained a number of broken bones and was taken to the John Radcliffe Hospital where he remains.
The deer died as a result of the collision, which happened at around 9.45pm on Monday, August 10.
Police are appealing for anyone who may have seen the motorcyclist prior to the collision itself or may have seen any deer on the section of road prior to the collision.
If you have any information about the incident call the 24-hour Thames Valley Police enquiry centre on 101 quoting URN 1534 10/8.
If you do not want to speak directly to the police you can contact the independent charity Crimestoppers anonymously on 0800 555 111. No personal details are taken, information is not traced or recorded and you will not go to court.