The two children are getting ready to feed the birds. They are standing on the shore of the lake, dressed warm for the cold weather.
What they don't realize is that the birds walking towards them are zombie birds. Their feathers are dropping from their bodies and their eyes are clouded over. As they honk, their calls are really saying "Feed, Feed."
Soon, the children will realize they are in danger. They will run to a nearby cabin and lock themselves in to protect themselves. The zombie birds will get lost in their own calls and wander up the shoreline looking for more food