Help with finding count of occurrences within a polygon layer

What I have is a polygon layer of study areas, then a point layer with records of observations, each observation has a collector number.
The observations are not accurate so they do not overlay the study areas properly but are related using a study area code.
I would like to be able to find how many collectors are active within each study area.

Does anyone have any experience with this?

edit: I should also mention that the number of observations within each study area can vary from 2 or 3 to over a few hundred.