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Topographic tales from tracking ocean wanderers

2018; Elsevier BV; Volume: 28; Issue: 16 Linguagem: Inglês

10.1016/j.cub.2018.06.061

1879-0445

Stephen C. Votier,

Marine animal studies overview

Animal tracking has revolutionised biological science. The emergence of devices sufficiently small to safely track wild animals (also called bio-logging), together with statistical tools sophisticated enough to interpret the huge data streams that tags generate, has provided groundbreaking insights into animal behaviour. This is especially true for seabirds. Although their definition is debatable [1Votier S.C. Sherley R.B. Seabirds.Curr. Biol. 2017; 27: R448-R450Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar], these birds spend the vast majority of their lives at sea and previous attempts to understand where they go, why, and to what end have relied on arduous boat surveys or snapshots provided from coastal headlands. These challenges left many unanswered questions — questions that seabird tracking is now beginning to answer. Michael Brooke’s book, Far From Land, provides an entertaining and highly digestible account of what we have learnt from the past three decades of seabird tracking research, and what we have learnt is nothing short of staggering. For instance, seabirds have the longest migration of any animal and tracking has revealed the true extent of this movement: an eye-watering 80,000 km round trip performed by Arctic terns (Sterna paradisea). Tags also reveal that albatrosses are able to circumnavigate the southern oceans — one of the windiest places on Earth — but expend little more energy than when sat on land. Tracking has also revealed the diving prowess of seabirds: emperor penguins (Aptenodytes forsteri) can dive for more than 20 minutes, to depths of over 500 m. Seabirds also do some unusual things to overcome the paucity of food in tropical seas: magnificent frigatebirds (Fregata magnificens) have the lowest body mass for their wing span of any bird and this light frame enables them to exploit warm air that rises from the sea, in much the same way that vultures do on land. In short, this book shows the huge diversity of movements both within and among species and how such behaviours can give rise to the low pace of life that characterises these ocean wanderers. Accounts of the research that has revealed these findings, beautifully illustrated by Bruce Pearson’s illustrations, form the basis of Far From Land. One of the key strengths of Brooke’s writing is its accessibility. He covers a wide range of topics and has a knack for simplifying concepts that helps the narrative to flow. For instance, stable isotopes are a widely used form of inferential bio-logging, but this can prove to be a tricky concept to understand. However, his section on stable isotopes is simple and easy to comprehend — an exemplar to others who write on this topic in a much more opaque language. There are also excellent explanations of the highly efficient flight styles employed by albatrosses, such as slope soaring (where birds use uplift produced by the wind that hits waves to generate forward movement) and dynamic soaring (where birds can extract energy by virtue of gradients in wind speed caused by friction close to the water’s surface). Once again, these explanations are characterised by their simplicity and insightfulness. Another nice feature of Far From Land is the inclusion of vignettes of seabird researchers. Many of the examples are accompanied by some insight into the person behind the research (including some nice anecdotes about the author’s experiences too). These are sufficiently brief as to not detract or drift into mawkishness, but they do hint at the diversity and nature of seabird biologists (I can attest that the seabird community is typified by many genuinely nice people — maybe this is linked to the personality traits required to thrive in the far-off places that these birds inhabit). These elements steer the book away from being too much like a textbook, although I would have been happy to see more of this personalised perspective of the science. So, is Far From Land any good? As a seabird biologist who is especially interested in tracking, it is perhaps unsurprising that I thoroughly enjoyed the book, yet I think it would appeal to a much wider audience than just the converted, such as myself. It is well written, tripping along at a nice pace, and should keep anyone with an interest in marine biology or ornithology entertained. It is something of a cross between a popular science book and a textbook — think A Short History of Nearly Everything (Bill Bryson’s fabulous 2003 popular science book) for seabird biologists. For this reason, I can see it being especially valuable to students with an interest in the topic. Certainly the students that I teach — both undergraduates and postgraduates — could benefit greatly from reading this book. I will therefore be recommending it.