I'm a new member of RSPB and would like to know what benefits there are besides entry and a magazine. Does membership include access to the international organization to which RSPB belongs? Discounts in the cafés?
First, a warm welcome to the RSPB Community.
Depending on what type of membership you've signed up for, have a look at the RSPB Membership pages online, or if you have your membership welcome pack, have a read through that.
I'm not aware of any discounts in the cafe's or for any other services, apart from access and parking charges which you'll be exempt from upon presenting your membership card to either the site reserve staff or by scanning the barcode on your card at the ticket machine.
https://www.rspb.org.uk/membership
Mike
Flickr: Peak Rambler