It's easy to bird Cuba on your own. Just get the Birdwatchers' Guide to Cuba, Jamaica et al if you haven't already got it and plan your own route. Hiring a car is easy. Once you get out of Havana the roads are deserted. There are homestays everywhere. we used them on both trips except for Cayo Coco where you have to use the hotels there. I put contact details of some guides in my first trip report on here. Angel is a lovely man and a great guide but didn't have a car when we were there - he only had a motorbike.