How the African cattle egret arrived in South America in 1930 remains a mystery, as does its later (1950s) appearance in Massachusetts. Oddly, too, the bird ""seems to have waited until conditions were just right"" to show up in Florida, which once had no large hooved animals but had by then become an important livestock area. Another mystery is the cattle's tolerance for its constant companion, who lives off the insects flushed out by the larger animal's movements, but does not seem to perform any reciprocal service. Even the bird's courtship behavior is strange; not only do both partners turn an exciting bright red but the displaying male, once his gyrations have attracted an audience, will drive off any other cattle egret, male or female, who comes near; the aggressive female must land on his back and peck his head, resisting his attempts to throw her off, until he is quieted. Scott begins this introduction with an evocative vision of the egrets in their native Africa, and he keeps you intrigued throughout with the birds' unique and puzzling behavior; Sweet's photos, superior as usual, include an excellent hatching sequence.