A pair of picture books make ideal introductions to spring or Easter basket treats. In Countdown to Spring! An Animal Counting Book by Janet Schulman, illus. by Meilo So, youngsters can count down from 10 to one as different animals frolic in the fields (""9 Butterflies. See them flutter by""). About the original, PW wrote, ""The illustrations provide the sweetest treat; laid with luscious brush strokes, So's cheerful, delicate watercolors delight the eye.""