Birds in Winter: Surviving the Most Challenging Season
By Roger F. Pasquier
Princeton University Press, 2019

Readers of recent terrific books like Scott Wiedensaul’s Living on the Wind or Kenn Kaufman’s A Season on the Wind will already be familiar with some of the staggering details of bird migration, and many of those details are on display again in Birds in Winter, the new book by Roger Pasquier, associate in the Department of Ornithology at the American Museum of Natural History (and author of Watching Birds, a thoroughly first-rate introduction to the world of birds). But here the emphasis is on one of the biggest reasons for those amazing migrations: the fact that at least a third of Earth’s bird species have to deal with winter. 

Those birds, and all other birds, have evolved over the last 155 million years in a broader context of glaciation cycles; some awareness of winter is buried deep in the genes of even the most indolent tropical layabouts. But Pasquier’s main focus here is on how birds deal with winter, either by avoiding it or by riding it out. Migrations involve significant risks, not only the ones inherent in travel but also in the fact that time spent traveling is time lost to foraging for food or staking out territory. These dense but smoothly readable chapters deal with all of those factors in almost exhaustive detail. 

In the process, Pasquier also indulges frequently in the kind of fact-heavy wonkish digressions that made his book Watching Birds so delightful. No birds hibernate (with perhaps one fugitive exception), for instance, and this naturally leads to a short discourse on sleep:

Roosting and sleeping are the two activities most available to choice for wintering birds. Actual sleep varies by species in total amount and duration of each bout, with cavity roosters likely to sleep through all the hours they are there, while birds in exposed situations may sleep only for very short intervals between scans for predators. In addition to its restorative benefits, sleep is the most energy-efficient way to pass the time in cold regions, provided the bird is adequately fed, because birds then typically lower their body temperature. Some highly aerial species that never land during the winter sleep while on the wing, if at all.

Birds in Winter is extensively illustrated in black and white by Margaret La Farge, and it’s written in a perfect pitch between professional-level scientific detail and popular-level general interest. It’s of course a staggering comment on the dire state of the 21st century that such a book must perforce include a final note not about the fragility of the bird species it discusses but rather about the fragility of winter itself, but even Pasquier’s walking-to-work observations of various species in New York’s Central Park compel him to include such a note. It’s entirely possible that a book titled Birds in Winter appearing in 2059 instead of 2019 would strike its readers as bizarrely anachronistic; in the meantime, this present appears at summer’s end in the Northern Hemisphere, when quite a few avian residents are in the final stages of their year’s biggest travel plans. 

Steve Donoghue is a founding editor of Open Letters Monthly. His book criticism has appeared in The Boston Globe, The Wall Street Journal, The Historical Novel Society, and The American Conservative. He writes regularly for The National, The Washington Post, The Vineyard Gazette, and The Christian Science Monitor. His website is http://www.stevedonoghue.com.