Caribbean sugar mills were powered by water, animals, wind, or steam, yet the evidence indicates major differences between islands in terms of which mill type predominated. We suggest that windmills offered few, if any, advantages over animal mills and several serious disadvantages. Why, then, were so many windmills built during the eighteenth century on some of the islands of the eastern Caribbean and so few on others? Here, we draw on Costly Signaling Theory to help explain these patterns. The preference for windmill-building may have had less to do with functional requirements or economic efficiency than with cultural competition, the signaling of membership of the planter class, and the display of power throughout the plantation landscape. [ABSTRACT FROM AUTHOR]