The Ending - Spoilers
When Melanie was driving towards the island, it had a close up of the two love birds in the car. They seemed to be leaning towards the turns. I think that they were the whole reason for the birds on the island going crazy.
In the end, the little girl asked if she could bring along the love birds because "they haven't hurt anyone" and then they drive off in the car bringing the love birds along. Could this mean it would trigger this to happen wherever they go next due to the birds? I could be way off, but that is what I got from the movie. Other wise why bother mentioning them at all? Just because she loved them? Remember also that none of these occurrences happened until Melanie got to the island.