Rigor Vitae: Life Unyielding

Thursday, July 13, 2006

JUST ANOTHER BIRD IN THE CITY

A couple of months ago, a friend and I negotiated that badly designed new section of Salt Lake City highway known colloquially as “the Spaghetti Bowl,” where Interstates 80 and 15 intersect. Fortunately, she was at the wheel, because at the very point where the driver's attention is paramount, I spotted an adult Peregrine tiercel (Falco peregrinus) perched on a tower beside the freeway. I saw the bird for but a moment as we rode the tangled ribbon of mechanized motion, borne on concrete towers as high as sixty feet, and snaking over several man-made water-bodies: as urban and artificial a wetland as one could imagine. The next day, I spent an hour or so riding my bicycle around the area, searching for falcon whitewash and remains of prey. Thirty years ago, it would not have occurred to me to look for a nesting site in such a location; I thought of falcon eyries as the the apogee of wildness, until I visited Munich as a teenager. In the center of the thousand-year-old Bavarian capital is the Marienplatz, a huge, busy, and picturesque square, dominated on its eastern edge by the twin towers of the Frauenkirche, a spectacular fifteenth-century church with half a dozen Common Kestrels (Falco tinnunculus) nesting in openings in the masonry. That year a pair of Peregrines fledged four eyasses from the top of the west tower. The young falcons spent each evening chasing pigeons right over the heads of the oblivious crowds.

By the 1970s, Peregrines had probably been nesting in old European cities for centuries, but in America they were just learning that behavior. Salt Lake was graced with its first Peregrine eyrie, on the face of an elegant old hotel, in the early '90s. Both birds sported yellow seamless bands, betraying them as captive bred; as did practically all “wild” U.S. Peregrines of the day.

Last year I rode through an unfamiliar Salt Lake neighborhood, when I heard the screaming of a large falcon. I modified my itinerary and steered in the direction of the sound, which led me straight beneath a little 14 foot freeway overpass. I couldn't believe a falcon would nest in such a spot, and indeed, one didn't. The sound emanated from a loudspeaker mounted under the bridge: an ill-conceived scheme to discourage roosting pigeons. My search at the base of the Interstate junction proved fruitless as well, but I remain ever ready to accept urban ornithological surprises. A century ago, Salt Lake erupted from a high desert valley, banishing Coyotes and badgers, Horned Larks and thrashers. In the early days, the city itself must have been a dreary place for a naturalist, but since that time, the fauna has been busily adapting to the original insult. Robins were the first pioneers, followed by a few woodpecker and warbler species. Scrub jays, chickadees, and House Finches were also quick studies. Presently the city witnesses a boom of Black-biled Magpies (Pica hudsonica), Mourning Doves (Zenaida macroura) and introduced California Quail (Callipepla californica). In a previous post I wrote about the astonishing speed with which American Crows (Corvus brachyrhynchos) have colonized the city, their population surging far faster than reproduction alone could accomplish. The new flocks must attract transient birds.

The popularity of that concrete wetland under the Spaghetti Bowl has grown exponentially during its five years, as some waterfowl have become increasingly urbanized. Thirty years ago, the sight of a few braying Canada Geese overhead was a rare treat for most Americans. A few decades of concerted habitat management later, you can't swing a male model without hitting one of the birds, leaving many of those same Americans cursing as they scrape up the scuz. Today the Spaghetti Bowl is home to many birds species, like Double-crested Cormorants (Phalacrocorax auritis), Western Grebes (Aechmophorus occidentalis), Forsters Terns (Sterna forsteri) and others that I never saw in the city prior to 1990, along with a variety of ducks, geese, coots, and other lesser surprises. I'm not the life list kind of birder, but chronicling the bird life of this spot would be worth the effort.

White Pelicans (Pelicanus erythrorhynchus) are common in the American West, and at the height of the migration you can literally watch millions of the huge birds flock over Salt Lake, but their nerve never materialized until recently. During last fall's migration they filled the Spaghetti Bowl's ponds. Gunnison Island, in the Great Salt Lake, is home to a huge pelican colony. The lake is far too salty for fish to survive, so for centuries the birds have flown twice a day to Utah Lake, fifty miles away, to fish for themselves and their offspring. This behavior, too, is changing. For the past couple of weeks, as many as 14 pelicans have fished each morning in a little duck pond in the park by my home. As you can see in the photo, even the lawnmower fails to perturb them.

I mention these stories only to shed some light on one dynamic of nature; this shouldn't be taken as excusing urbanization's speedy spread. Some creatures learn to adapt to the radical change of a city, but only a minority, and the diversity of fauna across the span of urban habitat worldwide is truly puny. In the recent internet conversation about Eagle Owls' (Bubo bubo) invasion of Great Britain, some American commentators suggested the species would behave like American Great Horned Owls (B. virginianus), and it appears that both species adapt rather easily to city life, but such assumptions shouldn't be made too quickly. To adapt to living in a city, a bird needs to have (1) habitat requirements that can find a compromise in its new home and (2) the psychological inclination to make that change. The fact of two young Killdeers (Charadrius vociferus) being fledged last week from a parking lot in my neighborhood should give little solace to their dwindling congeners the Piping and Snowy Plovers (C. melodus and alexandrinus). Prairie Falcons (F. mexicanus) still outnumber Peregrines 15 to one here, but I don't ever expect them to nest in the city. Any falconer who's worked with both birds knows how much more offensive a creature a human is to the former species. Among the the many tens of thousands of vertebrate species, I've gotten to know but a very few personally; still, my guess is that the Prairie Falcon's attitude is not only more typical, but more justified.
_____________________
upper: THE PLUMING POST--PEREGRINE FALCON & ROCK DOVE (1989) acrylic 30" x 20"
lower: Pelicans photographed by CPBvK July 12, 2006

5 Comments:

Anonymous rob said...

Great post. I'm constantly torn between surprise and pleasure that some birds are adapting to the city, and absolute horror at how many other species are being displaced by urban growth. Utah is ground zero for a lot of this kind of change, as suburbanization and growth of exurban housing developments have obliterated so many native habitats in the last 15 years--making nice homes for robins and quail, but displacing the species that have spent the last few million years adapting to the arid West.

7:53 AM  
Anonymous DouglasG said...

I too have recently seen a Peregrine. I knew they frequented the area because of the occassional pigeon leg I would find here or there. However, I had never spied one until yesterday...

9:56 AM  
Blogger Lord Garavin said...

What an excellent post, Carel, not to mention your beautiful artwork. Your observations are spot on. Here in Rochester, NY we've played host to a pair of Peregrines since 1998, both unbanded. They nest on the headquarters building of the Eastman Kodak Co, and as you'd expect from the "World's Imaging Leader", they have their own website complete with 5 cameras. The site's been closed for the season since the fledglings have left the nest, but a dedicated cadre of watchers keeps an eye on the fledglings until they disperse.

I have no talent for painting, but I'm a passable hand with a camera, and our local falcons are my favorite subject. If you're so inclined, check my blog for some recent photos and commentary.

3:50 PM  
Anonymous Roger B. said...

Very interesting. I recently wrote about urban peregrines in the UK, so it was good to get a US perspective.

Your comments about Canada geese were also interesting. They are rapidly becoming a problem species here in the UK. From central London to the Cairngorm Mountains there's hardly a lake in Britain that doesn't have a burgeoning population of Branta canadensis.

2:36 AM  
Blogger cpbvk said...

Rob: Utah certainly is under extreme pressure. Expect more commentary on that. My favorite places seem to get defiled faster than I can find new favorite places. At least there's plenty of opportunity to watch these interesting changes.
Douglas: Since the end of agricultural application of DDT and the instigation of captive propagation and reintroduction, it's possible to see Peregrines just about anywhere. In cities, most people don't notice them, since they don't look that different from a pigeon to the uninitiated.
L.G.: Thanks for your remarks. I enjoyed your wonderful falcon shots.
Roger: It's interesting to hear that urban Peregrines are a new phenomenon in the UK. Do you suppose they nested in London pre-DDT? I should mention that my assumption about them nesting in European cities for centuries was purely speculative.

8:19 AM  

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