There are lots of dogs on Vieques that, while not exactly wild, don't have any real home or owner. The Vieques Humane Society
http://www.viequeshs.org/ makes a valliant effort to find them homes (to the point of flying them to people in the US!) and get them spayed or neutered, but they're always over capacity and having to turn dogs and cats away. (You can donate on the website!) Many Viequenses don't really see a need to get their pets fixed or any problem with them roaming the neighborhood as they want, so the problem is a difficult one to tackle.
We have a family (3 generations, 5 or 6 dogs) that lives in our neighborhood that has had at least three litters since we've been here. They usually hang out at a
semi-abandoned house and one of our neighbors feeds them here and there, but definitely not enough. Of the recent litter of four pups one has already died and it looks like they've driven out the next weakest. He was huddled in front of our gate last evening.
We've been chasing them back down the hill when we see them hanging out in front of our house as a group, but on his own he was too pitiful to turn away. He's obviously been in some fights with his siblings, has a patch of fur missing on his side, and was very hungry. So we've taken him in for the moment. Charlotte (our Jack Russell Terrier) has been surprisingly OK with him. We're a bit torn on wherer or not we're willing to keep him. We'll take him to the vet on Monday and see where things go from there.