Complex sentence: But as immense flock of birds begin massing around Gull Island, it becomes clear that something is very wrong in this isolated, deceptively calm oasis and fear mounts as a marine biologist is the target of a mysterious, grisly attack.
Split into simpler sentences: But as immense flock of birds begin massing around Gull Island, it becomes clear that something is very wrong in this isolated, deceptively calm oasis. The fear mounts as a marine biologist is the target of a mysterious, grisly attack.