Sayre (If You Should Hear a Honey Guide, 1995, etc.) using "home at last" as her refrain, achieves an evocation of the ancient rhythm of migration, as warbler, salmon, green turtle, and wood frog mark the passage of the seasons as dictated by their biological imperatives. There are also a number of more incredible examples of migration: millions of monarch butterflies travel thousands of miles, Arctic terns cover half the globe in their peregrinations, spiny lobsters in lockstep formation poke along at five miles a day. Research into migration has yielded some tantalizing notions, of magnetic directioning and star paths and chemical traces, and Sayre includes some of this material, lightly in the text and more fleshed out in an explanatory spread at the end of the book. Text and the soft pastels impart the timelessness of migration, and may strike a deep chord in young readers. (Picture book. 4-8)