Walsh's (Mouse Paint; Mouse Count) mice characters here deliver a somewhat disjointed nature lesson. Spying a young oak tree, "detectives" Dot and Jabber set out to find the larger oak that produced the acorn that sprouted into the smaller tree. After a mole points them in the right direction, the duo wonders how the acorn traveled from the bigger tree to the location of the newer tree. ("Do you think it walked?" asks Jabber). Reaching the large oak, they discover their unexpected answer (they observe a squirrel making off with a newly fallen acorn and burying it in the ground). A concluding note explains alternative ways in which acorns travel from place to place (moved by water, birds or people). More distinctive than the narrative, Walsh's spare, cut-paper collage art has a three-dimensional look and gives these inquisitive mice an appealing, comical quality. Ages 3-7. (Sept.)