Are you certain there are no rescue organizations in your area? We have both a reptile refuge and a wild bird (owls, eagles, hawks etc) sanctuary up here in the lower mainland of BC. We even have places that will take sick, injured or young seagulls. I would phone the humane society just in case. I am certain that they could help you or at least give you some advise or direction on what to do with them.
It really bothers me when people just abandon their animals. You should see the amount of iguanas, snakes and even snapping turtles and caymens that they have at the reptile refuge up here! I have been there a couple of times and there are plenty of horror stories. And people wonder why I have more respect and love for animals than I do my own species.