what is census capitation?
In Scouts (there is similar in Guiding, but the details are different) every young person pays an annual 'fee' to the Scout Association. I believe most Counties and then Districts put a surplus on top, so the amount varies, wherever you are in the Country, but it is about £38 - £40 here.
This covers HQs costs, (Staff, buildings,etc.), legal support, liability insurances, all training courses for adults, volunteers costs (not many claim, but we don't want anyone not to be a Leader because they can't afford the costs), occasional equipment costs (eg a projector for the training team), things like room hire for County meetings or Regional meetings, and probably a lot of other things I can't think of at the moment.
Well organised groups include that figure in their budget and break it down into the subs everyone pays every month / term, or does a fund raiser, or uses recovered gift aid to subsidise it or whatever, and less organised groups give all parents a bill, in January.