Holly's arrival lets the other rabbits know that something terrible has happened to their old warren. For the Captain of the Owsla to be so badly injured and to have traveled so far from the warren suggests some sort of awful event. We see that Fiver was right all along—they did need to leave their home. Although the other rabbits no longer need any further reason to trust Fiver, Holly and Bluebell bring up the point that leaving their home warren saved their lives, but brought no guarantee that things would be easy. They have been beset with dangers since they left. Blackberry's suggestion that they build their own warren gives them a chance to make the downs a true home. The rabbits have wandered for a long time, but know they have found a good living environment. When they finish constructing the Honeycomb and the rest of the new warren they will have a permanent residence.
Hazel does a very strange thing when he rescued the mouse, and it shocks the other rabbits. Although he acted on a sudden whim, his action further demonstrates that this group of rabbits is acting differently. Throughout their trip, and at all the other warrens they have visited, they have viewed other creatures as either enemies or nonentities. Now, however, Hazel has befriended a mouse by saving its life, and the mouse has promised to do him a favor in return sometime. The possibility of cooperation with other animals does not appear to have much precedence in rabbit history—with the possible exception of the stories of El-ahrairah—but it seems like a good idea. Hazel continues to prove himself a capable leader who thinks about things from a new angle. Although Hazel is not as insightful as Blackberry, he is better able to think about the whole group and what they need to do than is any of the other rabbits. If the mouse can help them sometime in the future, his act will not have been in vain. Either way, it costs him nothing to help the mouse, so it that regard is a wise decision.