It took just one sighting of a swallow-tailed kite to dispatch Susan Cerulean on a pilgrimage through its fragmented and ever-shrinking habitats. In ""Tracking Desire"", Cerulean immerses us in the natural history and biology of Elanoides forficatus. At the same time, she sifts through her past - as a child, student, biologist, parent, and activist - to muse on a lifelong absorption with nature.