Snowbird: Integrative Biology and Evolutionary Diversity in the Junco and . (eds.) 2016. University of Chicago Press, Chicago, IL. xiv + 389 pp, 8 page color insert, B&W photos and many figures. ISBN 9780226330778. $60 (Hardcover). Also available as an e-book.
“Indeed, there is not an individual in the Union who does not know the little Snow-bird” (Audubon 1831). This quote is used by the editors in their Introduction to Snowbird as a way to emphasize the seeming commonness of the junco. In fact, it is this commonness in North America that has allowed the junco to play such a large role in our understanding of organismal and evolutionary biology. Snowbird is about juncos, but it is about so much more than a small genus of birds. The contributors to this volume have done a wonderful job of illustrating how a research focus on just one taxonomic group can greatly benefit multiple fields of biology. This book joins a handful of recent books (e.g., Losos 2009, Martin and Ghalambor 2015) that have convincingly argued for the importance of focusing on organisms and their natural history for a better understanding of general concepts in biology. The editors of Snowbird did an admirable job of integrating seemingly disparate topics to make the point that studying juncos can significantly advance the fields of integrative and evolutionary biology. The larger lesson is that this could be true for any taxon if one works at it in an integrative and collaborative manner.
Snowbird is divided into four parts, each implicitly and explicitly connected throughout the book. Each part has a preamble that is a very useful synthesis of what is to come in the chapters for that section. Part One (Chapters 2–3) gives a historical context to the importance of the genus Junco as an exemplar in past, current, and future studies of integrative and evolutionary biology. Part Two (Chapters 4–7) does a remarkable job of synthesizing what initially began my interest in juncos: endocrinology, physiology, life histories, and evolutionary ecology. There are several reviews of the decades-long research program of the Ketterson–Nolan lab, even fairly recent ones, but these chapters have just the right balance of breadth and depth to make them stand out from any one (or two) review paper. Each chapter focuses on a particular aspect of junco biology, but connects to the adjacent chapters in the section well. Males and females are both covered, as well as the many correlational and experimental studies. Modern genomic approaches are included here as well to show how emerging technology can be applied to old questions. I usually feel that overhyping current technology can be risky because the technology will inevitably change, dating the book; however, these chapters do a good job of avoiding this possible problem, and instead focus on their current and potential future utility. Part Three (Chapters 8–9) focuses on the evolutionary diversification and systematics of the genus Junco. This was the topic I was least familiar with, which made it all the more fascinating. The five major lineages appear to have diverged very recently, and the two lineages that many readers will be most familiar with, Dark-eyed Junco (Junco hyemalis) and Yellow-eyed Junco (J. phaeonotus), are fairly homogeneous with the neutral genetic markers studied. Chapter 8 presents the first preliminary molecular phylogeny of the entire genus with good sampling, but future molecular work will be required to fully understand divergence within the large, homogeneous clade mentioned above. This is especially true in light of the observation that there is tremendous variation in color patterns, but with seemingly high genetic similarity. Chapter 9 proposes the possibility that unidirectional migration and chromosomal inversions may help us better understand this mystery. One extra gem was in Part Three: the preamble gives a wonderful account of how collaborations develop between investigators in seemingly disparate fields and across vast geographic distances. Up-and-coming scientists should take this to heart and follow this example. Part Four (Chapters 10–14) delves into mechanisms of divergence among populations given the topics already covered in the preceding sections of the book. Because of the recent divergence within Junco, there are many opportunities to study historical and real-time divergence events. Chapter 10 wonderfully summarizes a phenotypic comparison between a very recent urban colonization and likely colonizers. Much can happen in a few decades! An important take-away from this part, as emphasized in Chapter 11, is that mean population differences do not always predict within population patterns, and I think this is applicable to many species. Chapters 12 and 13 cover cues that individuals use to communicate. Although many will be familiar with the visual and acoustic cues used by juncos and other bird species, the evidence for olfactory communication (Chapter 12) was very tantalizing, and I look forward to further research on this front! Chapter 13 details the intricacy and mystery of junco song, as well as the unexpectedly low song complexity in the genus. Dark-eyed Juncos display a high rate of improvised or invented songs during development and very low rates of song sharing among males compared to other species. The reasons why should keep investigators busy for some time!
Chapter 14, although included in Part Four, easily stands alone as its own section of the book. Here, the editors Ketterson and Atwell lay out an exciting agenda for future studies centered on juncos (and beyond). Each chapter has suggested avenues of moving their field forward, but Chapter 14 really synthesizes what we do not know and prioritizes what we need to know. This chapter is not just a recap of previous chapters. I was very impressed with the somewhat unconventional organization of this chapter. It begins by looking back at what the Birds of North America species accounts for the Dark-eyed and Yellow-eyed junco suggested as knowledge gaps. We have filled many of those gaps, but some still remain. They then make novel and synthetic recommendations for how to advance each of the fields covered in Parts Two–Four. Finally, they conclude the chapter by articulating to which fields in biology juncos can contribute. These include ecology; divergence, speciation, and microevolution; and organismal biology. The latter field is crucial, as they point out, because a focus on organismal biology will allow those in different disciplines to understand each other's work and work together. This is essential as biology continues to become a trans-disciplinary field.
Snowbird was written for science professionals, including undergraduate and graduate students, as well as birders, educators, and naturalists. This was a successful goal, and I would recommend it highly to my colleagues and students who have an interest in integrative and evolutionary biology. The book has much technical detail, but not so much to be off-putting, and it is not too laborious to read. All too often edited volumes do not integrate well, and the result is a somewhat haphazard collection of related papers. That is not the case with Snowbird. Each chapter cites other chapters frequently, and those citations span the various conceptual parts of the book. It reads as a well-planned, integrative volume. I have very few problems to mention. There are very few typographical or editorial errors, and each chapter is well written. The only thing that I think could have been improved is how the various endocrine axes were described. There could have been an earlier, full explanation of how the hypothalamus ultimately influences the gonads and adrenals to then in turn influence target tissues in a variety of ways. As it is written, this is given on a need-to-know basis. The information is there and adequate in every case, but there is redundancy in several chapters. On a positive note, that redundancy lets each chapter stand alone, and perhaps that was the ultimate goal. The final chapter is presciently titled, “Standing on the Shoulders.” Perhaps the editors meant the early work by Jonathan Dwight or Alden Miller, or the extensive work by the Ketterson–Nolan laboratory, or maybe the recent work by the many others that contributed to or inspired this volume. Regardless, Snowbird represents an impressive set of shoulders on which to stand and guide us as we learn about our natural world.
