Flying up the Bird Tree

• Leonardo Campagna
• Trevor D. Price

DOI:https://doi.org/10.1016/j.tree.2018.10.001

In The Ascent of Birds, Reilly presents a walk up the backbone of the avian tree of life, starting with the basal ratites and ending with the flowerpiercers, a group of 18 tanager species that ‘gave up fruit for nectar’. The book consists of 27 chapters, each forming a pithy essay describing some special features of a clade or unusual species. 

The essays pay special attention to the timing of the major geological and biogeographic events that have shaped diversity in the clade (sometimes, as in discussion of the geese, in great detail) or the origin of a distinct species. 

Beyond that, the author seizes on special features that have captured his interest, especially morphological and physiological adaptations, and, when known, their genetic underpinnings. Reilly is both a scientist and a keen birder who has observed birds in remote corners of the world, illustrated by his account of the peculiar cow-like smell of the gut-fermenting hoatzin ( Ophisthocomus hoazin), a species on one of the longest branches in the avian tree of life (i.e., a bird with no living close relatives). 

Although, generally speaking, birders focus more on pattern than process, Reilly delves into the latter. This makes the book an excellent introduction for anyone interested in learning about the diversity of life, and its origins.