Good Afternoon Deanna,
One of the best ways to to know exactly what new developments are about to happen in the communities of the Bronx would be to call each Community Board (12 of them) in Bronx County to find out when the Land Use Committees meet. You can google (Community Boards in Bronx County) to get the numbers or just call 411 and ask for any community board (1-12) and the operator would give you the specific board.
This is a great way for you as a potential buyer to become familiar with the community when it deals with land use and land/community development. This is the starting point for developers to present what they are looking to build in each respective community. This is also a great way for you to become more active in the different communities.
I hope this is beneficial to you.
Luis A. Sterling, GRI, e-Pro, Realtor