Which ports? And what time of year? You see Ani and bananaquits most everywhere. (Bananaquits are a hoot, very bold). If going to St. John the US Park service has some pubs detailing the birds seen there. Some of the more unusual birds there are least and Roseate terns and brown pelicans. St Tom and St Maarten are pretty built up, but supposedly Northern Parula warblers can be seen in "moist woodlands" during winter. There are good guidebooks detailing birds of the Carribean and Mexico, depending on your itinerary. (But the best, most birds we saw in the Carribean were in El Yunque sp? rainforest in Puerto Rico.)
Carla