[Note: this is a slightly-modified version of a posting I made originally to the Rocky Mountain Raptor Program listserv]
If you attended rounds last night or just read Joelle’s Rounds Notes, you know that this promises to be a great day, as 16 Swainson’s Hawks, many of which have spent an entire year or more in our care, will be released to take part in one of the great natural spectacles that our world has to offer. I will be tagging along for the release today, helping where I can of course, but also there to catch a glimpse of the birds which will depart in the next month for the pampas region of northern Argentina, a one-way trip of nearly 5,000 miles. Along with migrating Broad-winged Hawks, Mississippi Kites, and Turkey Vultures, they fly over places like Veracruz, Mexico on their way south in astonishing numbers – the so-called “River of Raptors” in Veracruz in the fall regularly documents as many as 50 THOUSAND Swainson’s Hawks flying through a *day* during fall migration. The total number of raptors passing overhead there in a season is over 3 million.
Now, if you’ve been with the program for any length of time, and helped with any of the programs or exhibits or just overheard the handlers talk about our educational birds, you’ve likely heard the stories about the Swainson’s Hawks and their epic migration. You may already know these birds spend their summers in North America, largely in the American West ranging from northern Mexico up into southern Canada, from as far east as the high plains to as far west as the Central Valley of California. Starting around now they begin to assemble into larger and larger groups, as recently-fledged young disperse from their nesting locations. The young however need to find these groups, because they don’t know the way to go. Apparently past experience with rehabilitating first-year Swainson’s Hawks has shown this to be the case. It’s quite a testament I think to how some birds, even those who we tend to think are not very intelligent or socialized, actually DO use their brains, cooperate at least in some way, and have the ability to be very receptive to new knowledge.
As a handler I’ve often heard other handlers refer to the juvenile Swainson’s Hawks as “young and dumb”, and I wouldn’t necessarily argue against that, having seen how they behave in their flight cages. But think about it — after these birds have completed an annual migration cycle, where they’ve paid attention to landmarks along the way, and having been guided by seasoned adults, they are then in subsequent years able to do the trip themselves, and even lead the way for the next generation. That’s called LEARNING. That means they have good memories, that they were paying attention to where they were, to whatever other sky phenomena they may use to guide themselves on this remarkable journey through vast desert, urban, rainforest, and savanna biomes. How is that any different from how WE are? Who among us is so inherently brilliant to have mastered so many life skills without the guidance of at least someone at some point? Well, maybe a couple of us, I don’t know, but certainly not me. For my part, I can say that in this specific way, I identify with the Swainson’s Hawk. Inasmuch as the birds we are about to release today are going to embark on the epic journey that will define the rest of their lives, I salute them and admire them for what they are about to do, and for the symbol of freedom, exploration, and determination for survival that it represents. What better demonstration of the capacity for growth and change and self-improvement is there, than to answer the call of one’s inner nomad like this?
This weekend I helped out at New West Fest, and on Saturday we had the female Swainson’s Hawk on display at the booth. At one point, I was relating the great Swainson’s migration to a booth visitor, describing the migration route they take. I told him that they assemble in North America, fly together in enormous kettles through Central America (Honduras, Costa Rica, Panama, etc.) and then reach the Darien Gap which connects Panama to Colombia and the rest of South America. I then said that after that we don’t really know where they go next, just that after another couple weeks they are in northern Argentina.
But I was mistaken. We now actually DO have a pretty good idea about where they go. Take a look at this map:
Swainson's hawk migration route. Data from USGS, Snake River Field Station, from 30 birds fitted with satellite tracking devices.
This is a map compiled recently from a study involving the fitting of satellite tracking devices onto migrating hawks. What is astounding to me is how, once they arrive in South America, these birds take as direct a route to their wintering grounds as possible. They’re not spreading out over the vastness of the Amazon, lost or confused or distracted – no, they know exactly where they need to go, and they’re not messing around. And don’t be misled by that little bend they take in their path around central Bolivia – that is a strategically smart detour they take, because that allows them to not waste energy flying over the unforested high Andes and the resource-sparse altiplano. It’s brilliant really, but it’s only in the past few years that we now have the scientific data to demonstrate just what these birds do on their southbound trip.
Back to the booth this weekend. I got to give my own Swainson’s spiel of course, but also listen to other handlers’ spiels, which was very interesting to me. In general, and this applies for any booth experience, people are initially confused by the mere name “Swainson’s Hawk”, as most laypersons have never heard that name before. Handlers tend to then explain, myself included, that the bird was named after someone named Swainson, which seems true enough, but then also add in, only half-jokingly perhaps as a way to bond or connect with the person we’re talking to, that Swainson must have had a big ego to name a bird after himself. After hearing that apocryphal explanation several times that afternoon, I got to wondering, what’s the real story there? Did Swainson really name a bird after himself? So, that night after I got home I did a little research…..
There was indeed in the early 1800s a British man named William Swainson. He was one of many amateur naturalists in that era who essentially were professionals, once they had a regular source of income that could pay for the time it took to collect specimens and participate in nature societies like the Linnean Society, of which Swainson was a part. In his case, he “retired” young on a military pension, and spent the rest of his life indulging his real passion, which apparently was studying animals and making illustrations. He became quite accomplished at making lithographs. He was one of the first if not *the* first person to make pictures like this, and I encourage you to do a Google image search on “Swainson’s lithographs” to get an idea of the kinds of illustrations he made. John J Audubon was an admirer of his, for good reason. Swainson worked with another naturalist named John Richardson and in the late 1820s they produced a volume called Fauna Boreali-Americana, which featured hundreds of Swainson’s excellent depictions of birds observed and collected by Richardson in North America. From what I can tell, Swainson himself never visited North America, although he did spend a fair amount of time in Brazil.
Anyway, one of the birds depicted in the book was indeed what we now call a Swainson’s Hawk, but of course it wasn’t identified as such in it. Richardson had described the bird as a form of Buteo vulgaris, which is now called Buteo buteo, basically the Common Buzzard of Eurasia. (The Common Buzzard is a close relative of all buteonine hawks, which if you aren’t aware, includes Red-tailed Hawks, Rough-legged Hawks, Ferruginous Hawks, Broad-winged Hawks, and many others.) A different naturalist some years later, Charles Bonaparte, noticed this and corrected this error. He knew that the bird in Swainson’s illustration was a different species, and it was he, NOT William Swainson, who was the first to give a scientifically correct description of it. However, he too was an admirer of Swainson’s work, and in tribute to his great lithographs, he named the bird after Swainson, Buteo swainsoni. And THAT is how the Swainson’s Hawk got its name.
In this manner, Swainson had other types of birds named after him too, including the Swainson’s Thrush, Swainson’s Warbler, Swainson’s Flycatcher, and Swainson’s Toucan (now usually referred to as the Chestnut-mandibled Toucan, although the scientific name still bears the swainsoni tag). From what I can tell, in that era of discovery and exploration in the 1800s it was actually quite rare for a naturalist to name a bird after himself – instead, he usually named it after someone else who he admired, or otherwise though deserved mention in some way. That’s still generally true I think.
That all said, I did also learn though that it’s not unfair to posit that Swainson probably did have a big ego. In an unrelated matter, Swainson later in his life moved to New Zealand, and a few years after that was offered a position as a “Botanical Surveyor” in Australia, based largely on his sterling reputation as a naturalist and illustrator. However, Swainson had little or no real experience with plants, and other more knowledgeable and experienced botanists of his day were more than a little annoyed at his simplistic and casual approach to describing new plants in Australia, where he took it upon himself to name hundreds or even thousands of species of plants, many of which weren’t really separate species in the first place.
In my book, that takes some cojones and an ego, to go into a field that you know you’re not an expert in and just go all willy-nilly on a naming spree, just because you can.