The Origin and Distribution of Birds in Coastal Alaska and British Columbia: The Lost Manuscript of Ornithologist Harry S. Swarth. edited by Christopher W. Swarth. 2022. Oregon State University Press, Corvallis, OR, USA. 170 pages. ISBN 9780870712050. Paperback ($29.95).
Harry Swarth (1878-1935) was a prolific ornithological explorer, curator, collector, and thinker. In 2019 his grandson Christopher found a manuscript that Swarth had completed shortly before his death. The unedited manuscript, which is based on over 1,000 days of rugged expeditions to southeast Alaska and adjacent British Columbia between 1909 and 1934, forms the core of this book.
In the century-old manuscript, Swarth compares the coastal “Sitkan District” (Southeast Alaska; the “panhandle”) with the “Cassiar and Omineca Districts”, in British Columbia just inland over the icy ridges of the Coast Mountains. He reflects on his extensive collections and observations and explains a phenomenon that to this day continues to puzzle many birders who visit the region. If only this had been available to read when I moved here 30 years ago! Like many birders from eastern North America, when I ventured this far west I expected to see the “western” birds. Instead, at a longitude that’s as far west of Vancouver and Seattle as the Great Plains are east, birds are in their eastern forms: Myrtle Warblers, Slate-coloured Juncos, and Yellow-shafted Flickers. Why is that? Well, Harry Swarth makes sense of it. Even now that we know a whole lot more about biogeography, glacial history, and evolution, Swarth’s explanations still ring true.
One of Swarth’s passions was investigating geographic variation, and the origins of bird distributions. He was intrigued by the distribution of western forms like Red-breasted Sapsucker and Rusty Song Sparrow (then considered a full species; there were more splitters than lumpers back then). Their ranges extend all across southern B.C., but further north their range narrows, and at the northern extreme they are restricted a very narrow band along the Alaskan coast. After years of observation and analysis, he surmised that landbirds on the Alaskan panhandle originated from straight south, while landbirds in B.C. east of the Coast Mountains, even though their ranges extend very close to the Pacific coast, had their origins in a broad area extending to the Atlantic.
Hence the Slate-coloured Juncos in southern Yukon look almost the same as those in Ontario, while a couple hours’ drive away in Skagway, Alaska the nesting juncos are Oregon. A simpler theory of geographic variation of birds may have been that widespread species separated into isolated areas and gradually became distinct. But Swarth finds many examples among his collections and observations that support the alternative scenario, that subspecies that live side-by-side in this region did not diverge from a common form; they arrived from different directions.
Swarth made several expeditions, each 3-5 months long, to this region, traveling by boat and on foot. His extensive exploration of the Alaskan panhandle included 32 field camps from Juneau to Ketchikan and beyond. In British Columbia he spent time on Vancouver Island, and north of there in the Skeena and Stikine river valleys as well as in the vicinity of Atlin, including Carcross, Yukon. Travel at that time from Swarth’s home in Berkeley, California to Atlin, B.C. took at least a week and involved trains alternating with steamships on ocean and lakes, via Alaska and Yukon. Fishing and hunting provided sustenance during the expeditions, each of which included Swarth and just one field assistant.
The book consists of the full original manuscript (74 pages including photographs), plus maps, itineraries, and excerpts from Swarth’s field notes. Swarth’s passion and sense of humour come through in both the manuscript and in the field notes. He wrote in an engaging style that generally fell out of favour in ensuing decades but is now refreshing and entertaining to read.
His descriptions will connect with those familiar with the region:
“The Sitka Spruce…grows in such density as to suggest…a particularly thick pelaged fur. The view that meets one from a coastal steamer, day after day, is of an interminable series of vistas of dark green slopes covered with almost unbroken stands of conifers, the generally green coloration so thickly speckled with gray dead trunks as to produce almost a pepper-and-salt effect.”
“The poplar woods are pleasant to be in at any time, but in the fall…there is one peculiarly charming quality developed, one that is most manifest on gloomy, overcast days. The yellow foliage has exactly the tone of brilliant sunlight, and stepping from the dense shade of spruce timber…one receives the impression of a sudden clearing away of the clouds overhead, with the resultant burst of sunshine. Time and again…I have had to correct an erroneous impression…a conviction so strong that it was hard for one to be otherwise convinced.”
Swarth had no knowledge of glacial refugia or island biogeography, both fields that have developed more recently, but had a grasp of those concepts nonetheless. He surmised from his observations that the retreat of glaciers from the Alaskan panhandle was far more recent than east of the Coast Mountains:
“…there are hundreds of square miles of unvaried spruce forest, dark and cheerless, and almost birdless. On some of the westernmost islands in particular one can easily yield to an impression that everything is so new and unfinished that the birds have not yet found the place.”
For researchers and birders from the region, or traveling there, the book offers a fascinating view of the state of our bird fauna a century ago when there were few roads and forest clearings, and when some of the major glaciers in southeast Alaska were actively retreating. For naturalists and historians, there are entertaining and apt descriptions of the landscape, its flora and fauna, and the extraordinary efforts required for field work in this remote region in the early 20th century. For ecologists and climate scientists it gives perspectives on why and how species move into new areas – perspectives that are strikingly relevant for modern-day predictions of where and how northern species will move in our changing environment.
Photographs from the expeditions enhance the book, showing the landscape as well as the working conditions, equipment that had to be hauled to the field sites, small wooden boats relied upon for transportation, and the rough field settings in which specimens were prepared. Allan Brooks’ beautiful paintings add to the presentation; the artist was a friend of Swarth’s and his field assistant in the Atlin area.
The manuscript, field notes, trip lists, and handy glossary of early-1900s taxonomy are accompanied by chapters contributed by current-day ornithologists. These are helpful for putting Swarth’s work in context and answering an obvious question: do Swarth’s impressions and analysis still stand, a century later? What has changed, and what else do we know, about the birds of the region? Even for readers with only a passing interest in this area, the book is an engaging read due to Swarth’s deep insights and thoughtful analysis, his colourful writing style, and the extraordinary efforts required to study birds a century ago.
For many parts of the world, comparison of present-day bird life with a 100-year old manuscript would yield a story of declines, loss, and non-native introductions. But here, especially in the Sitkan region which has so recently emerged from underneath glacial ice, and also in the many other areas which have remained sparsely populated by humans, if anything the birds are more diverse, and in some cases more numerous, than in Swarth’s time. It would be fascinating to get Swarth’s take on the current state of bird populations here, especially the expansion of new arrivals taking advantage of a changing environment.
Pam Sinclair
Canadian Wildlife Service
Whitehorse, Yukon
Header photo: Danielle Brigida/USFWS
Suggested citation:
Sinclair, P. Review of the book The Origin and Distribution of Birds in Coastal Alaska and British Columbia: The Lost Manuscript of Ornithologist Harry S. Swarth edited by Christopher W. Swarth. Association of Field Ornithologists Book Review. https://afonet.org/2023/04/the-origin-and-distribution-of-birds-in-coastal-alaska-and-british-columbia/.
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