My favourite Rhino Saving charity recommends:
Work or volunteer in the conservation / charity sector
There are currently exciting opportunities at the Ol Pejeta Conservancy in Kenya. On their conservation programme, you will have the opportunity to help to create an effective monitoring programme for Northern White rhino, as well as to work on various ecological monitoring projects. This is a great programme to gain experience in the field, and we thoroughly recommend it. Please contact firstname.lastname@example.org for further details and see the links : OlPejetavolunteerpolicy.pdf & OPejetavoluntaryopportunities.
Also check the excellent sites below for voluntary opportunities and advice.