I cannot confidently say that chapter 30 has any kind of organized plot. A lot of action happens in this chapter, but the result is that the chapter has a "this happened, and then this happened, and so on." feel to it. The simple summary of the chapter is that Mr. Robinson and his sons are exploring a part of the island that they have never been to before. The new part of the island is much less tropical. It is more like a desert. The group sees something off in the distance, and it winds up being a flock of ostriches. The family decides that capturing one of the huge birds is a good idea. They ultimately fail at this goal. The dogs that they have with them end up freeing themselves and chasing the flock. The Robinson boys then let loose their trained falcon, and the falcon ends up killing an ostrich. They are all upset. Next, they find some ostrich eggs and decide to take them home. However, before going home, they decide to explore a valley area. Ernst goes off on his own, and then returns at a run while screaming. He is being chased by two bears. Mr. Robinson shoots and kills both bears, and the family returns home with the skins of the bears.