Who Goes Moo

This quartet of Animal Board Books features silhouetted photographs of birds and animals accompanied by pertinent statements or questions (``Mother penguin collects her own chick''; ``Who wears a collar and leash? Who wears a saddle?''). The photos are expectedly adorable, the brief captions straightforward and informative, and the production values high-however, in light of the many similar works crowding the bookshelves, the series has no particular luster of its own. Ages 1-4. (Oct.)