Pi based Camera trap/Trail camera/Wildlife camera

I have had several commercial wildlife camera traps. The biggest problem I have with them all is the "Trigger Time". If you have a fast moving animal (say a mouse running from cover to cover), most of the commercial offerings miss it completely.
A Raspberry Pi, running "motion" software traps all images and only records if there are a certain number of pixels different from one frame to the next. So no action is lost.
On a Raspberry Pi B+ an ordinary USB camera appears to record at about 5 fps