Bonjour Monsieur, comment allez-vous?
It sounds like you might have to be a bit of an explorer - the best way to set up a calendar is to do regular inspections and maintain a notebook - it will take time but it's a great way to learn about your bees and beekeeping on Reunion in general. As AllenF mentioned if there isn't a beekeeping society on Reunion it might be a great opportunity for you to get a group of like minded individuals together...
This monsieur might be a good place to start Francois Payet - Beekeeper - Le Tampon Region
I'm from St Denis in Reunion Island (21° south) and I like ti find a tropical beekeeping calendar, I was looking it for a while without chance by now
Could anybody help me?
Thanks by advance