The estuary as a survival location is a good one, for all the reasons you mentioned. But it would be interesting if someone had the money to do some testing on the water, plants and game in those areas. Most of the estuaries I've seen are overly loaded with algae due to chemical farming and manure runoff, plus all the other businesses that dump into the water sources, including community sewage operations.

You might be able to use snares to catch birds, but I'll bet you would need some practice. The easiest would be the scavengers, like gulls, using a chunk of waste meat on a hooked fishing line. But I have always assumed that scavengers would also be the least desirable. I would have to be pretty hungry to eat an opossum.