How to Know the Birds: No. 74, This View of (Bird) Life
How to Know the Birds: No. 74, This View of (Bird) Life
What: Olympic Gull, Larus occidentalis × glaucescens
When: Thursday, March 30, 2023
Where: Point Brown, Grays Harbor County, Washington
As gulls go, this one is impressively range-restricted. According to Doug Bell’s definitive 1996 monograph on the bird, it breeds north to Tatoosh Island off the extreme northwestern tip of the Olympic Peninsula and south to Coos Bay on the Oregon coast. Vagrants get around, dispersing south on the coast to the Baja peninsula and inland, more rarely, all the way to the Great Basin and even the Southern Rockies. The bird is a gull, after all, so some amount of vagrancy is to be expected. But it is concentrated mostly around the Olympic Peninsula; the Bell monograph pegs the area around Grays Harbor, Washington, as the distributional epicenter of this bird, known as the Olympic gull. And on a gray and drippy weekday afternoon in late March of this year, we found ourselves at Grays Harbor, in the company of birds like this one:
It’s an exemplary Olympic gull, with the wingtips a bit darker than, but not all that much darker than, the mantle, which, in turn, is a bit darker than, but not all that much darker than the mantles of the glaucous-winged gulls which proliferate around nearby Seattle. Shades of gray—that’s how it is with gull identification. Never mind all that, the Olympic gull is biologically fascinating, a point returned to over and over again in Doug Bell’s monograph, and reinforced in a Birding magazine article in 2005 by gull biologists Peter de Knijff, Andreas Helbig, and Dorit Liebers. The Burke Museum in Seattle, which we visited the next day, features the Olympic gull in a prominent “tree of life” exhibit in the museum’s main hall:
Yes, the Olympic gull is compelling for scientists, not to mention just a cool bird overall, but it’s also a conundrum for birders. An introgressed population of the western gull, Larus occidentalis, and the glaucous-winged, L. glaucescens, the Olympic gull is neither this species nor that species, so it doesn’t occupy an official slot in our checklists. On our day’s tally, the Olympic gull doesn’t earn a tick. Because it’s not a __________. Not a what? Yet it’s clearly a something, worthy of our notice. That’s what Bell and de Knijff et al. are saying, what the Burke Museum is displaying. And it’s what any visitor to Grays Harbor can see, plain as day, even on a day as dreary and drippy as that day we were out there. The Olympic gulls of Grays Harbor are Aldo Leopold’s “numenon,” the imponderable essence of a landscape: “Subtract the g[ull] and the whole thing is dead.”
“The grouse is the numenon of the north woods,” writes Leopold, “the blue jay of the hickory groves, the whisky-jack [Canada Jay] of the muskegs, the piñonero [pinyon jay] of the juniper foothills.” Then he announces, “I here record the discovery of the numenon of the Sierra Madre: the thick-billed parrot.”
Can you imagine traveling to the majestic pine forests of southern Chihuahua and declining to eBird the parrots there? Or scratching the pinyon jay from your New Mexico list, or deleting the entry for ruffed grouse in your field notebook for a brilliant autumn afternoon in Pennsylvania?
Hold that thought. We’re going to return to our Gedankenexperiment in just a moment. But a quick digression for now—for this bird, out there with all the Olympic gulls:
It’s a crow of course. And, contra the situation with gulls on the Olympic Peninsula, we have precisely one (n=1) crow to worry about in the region. This bird can only be an American crow, Corvus brachyrhynchos. But it wasn’t always that way. Until 2020, visitors to the region worried themselves silly about whether some of the crows there were a different species, the northwestern crow, Corvus caurinus. It turns out, though, that the erstwhile northwestern crow “is recognized as representing a geographical trend, rather than a species or subspecies, and thus is treated as a junior synonym of C. brachyrhynchos.” So decreed the American Ornithological Society in its annual “checklist supplement” published in The Auk.
Every crow on the peninsula—every crow in the entire Salish Sea region—has to be an America Crow. Any presumptive intergrade or intermediate between caurinus and brachyrhynchos sensu stricto is, effective 2020, just an American crow. Okay, but let’s not look past a bit of inadvertent apophasis in the AOS treatment: The northwestern crow “is recognized as representing a geographical trend.” That is to say, the bird is as interesting as ever. I made several recordings of the bird’s caw call, spectrographically a bit different from the crows I know so well in Colorado, and I recorded a weird two-note whistle I’ve never knowingly heard from any crow. I made videos of another crow capturing and consuming a crangonid, a behavior absolutely undocumented from Colorado. (Crangonids are coastal.) I even photographed a dropping, in case they figure out some day how to extract DNA from digital imagery. 😉
Nearby, yet another crow was kleptoparasitizing a shellfish from a second-calendar-year Olympic gull:
As with the crow wrangling the crangonid, we have here an ecological interaction presumably undocumented from Colorado and, for that matter, practically anywhere else beyond the Salish Sea and environs. Ecological interactions abound in the rocky intertidal zone. Like this one:
The particolored “starfish” are different varieties of the sea star Pisaster ochraceus, and the ovoid, seafoam-green blobs are a kind of anemone, the giant green anemone, Anthopleura xanthogrammica. Don’t be fooled by their apparent sedentariness. Like crows and gulls, Pisaster and Anthopleura are predators. I learned about Pisaster way back in high school in an AP Biology class; in a groundbreaking experiment that changed the entire field of ecology, the late Bob Paine of the University of Washington proved that the sea stars of the Olympic Peninsula are the “keystone species” in the fantastically complex rocky intertidal ecosystem.
“Subtract the grouse and the whole thing is dead,” according to Leopold. (I must fess up: Leopold wrote “grouse,” not “gull,” in his evocative “Guacamaja.”) And this corollary: “An enormous amount of some kind of motive power has been lost.”
Paine, who was active several decades after Leopold, showed that the power of Pisaster is more than motive. Subtract the sea star and the whole thing is actually, physically, literally, ecologically dead. Paine in fact subtracted Pisaster from small experimental plots and showed how community collapse resulted in the absence of “top-down control” by the voracious predators. Decades later, Paine’s findings have been unhappily replicated across vast spatial scales, as populations of Pisaster have crashed in the wake of anthropogenic environmental change.
Elsewhere on the sea rocks at Point Brown, we saw this:
You can probably see what’s coming next. The famous coda, today referred to as “The Tangled Bank,” to Darwin’s Origin of Species:
“It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us…There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.”
This particular bank is tangled not with birds singing and insects flitting, but rather with ochraceous sea stars and giant green anemones, with thatched and gooseneck and Pacific acorn barnacles. No matter. The generality of Darwin’s theory applies to tangled banks of all sorts, indeed to every other ecological community, on Earth.
Our visit to Grays Harbor was ending—our sojourn with ecologically distinctive Olympic gulls derived from the genomes of two other gulls, with behaviorally fascinating crows representing a geographic trend, with psychedelic sea stars in charge of it all, and more—and we took the time “to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us.”
There was one other player in this drama, his presence thus far only implied. This guy:
That’s me. A human. Produced by the same laws acting on the sea stars and Olympic gulls. Especially the gulls. Darwin didn’t know it, but we humans, like Olympic gulls, are intergrades. We are a composite, a chimera, of two species: Homo sapiens and H. neanderthalensis. The sapiens part of our genome is dominant, but the neanderthalensis component is not insignificant. Traits like blue eyes, blond hair, chest hair, and melanin-deficient skin, expressed by hundreds of millions of humans, reflect our Neanderthal heritage. Certain elements of human language may have Neanderthal origins, too, and, intriguingly, some of our most persistent cultural traditions, including religion, may also trace back to our Neanderthal antecedents.
Even more extraordinarily, every one of us—every human and every gull, every crow and sea star—is a perfectly assimilated chimera, or endosymbiont, of very distantly related prokaryotic and eukaryotic ancestors. Subtract either one from our humanity, with apologies to Leopold, and we would be gone in less than a heartbeat.
Neanderthals were not recognized as such until well after the publication of Origin (and we’re still in the process of revising our knowledge of H. neanderthalensis), and prokaryotes weren’t really understood as we presently understand them until well into the 20th century. So Darwin obviously didn’t know any of the fine details of the evolutionary checkered past of humanity. But he saw the big picture. I’ve written elsewhere that Darwin was insistent on the view that there’s more, much more, to understanding and appreciating life on Earth than worrying about whether a population of organisms is this species or that species. Not a one of us, I think it’s safe to say, would propose to delist the endosymbiont H. sapiens×neanderthalensis, the human being, from the book of life.
Same goes for the Olympic gull, wouldn’t you say?
Ted Floyd is the longtime Editor of Birding magazine, and he is broadly involved in other programs and initiatives with the ABA. Ted has written 200+ magazine articles and 5 books, including How to Know the Birds (National Geographic, 2019). He is a frequent speaker at birding festivals and has served on several nonprofit boards. Join Ted here for his semimonthly spot, “How to Know the Birds,” celebrating common birds and the uncommonly interesting things they do.
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