I didn’t expect a seabird, a violin, and a pair of dividers to have much in common—but this voyage has a way of connecting strange dots. One moment we’re drifting through the foraging range of the rare spectacled petrel, hoping to spot its wingtip brushing the water; the next we’re learning to measure nautical miles with old-school tools in a navigation workshop. And somewhere in between, our naturalist Greg—equal parts showman and snake-whisperer—introduced us to a gallery of brilliant and delightfully bonkers naturalists who once mapped the wild world in their own eccentric ways.
Spectacles on a Bird
Inaccessible Island is the primary breeding site of the rare spectacled petrel (Procellaria conspicillata), a seabird that returns here each year from September to March. They nest in burrows and begin laying eggs in October. Chicks hatch in December and fledge by March.
When we cruised past Inaccessible Island, the skies were quiet—most of the birds had already left. But now, as we sail within the eastern edge of their foraging range, not far from South Africa, a few have found us.
For the past several days, spectacled petrels have followed our ship. They skim low over the surface, dipping into the wake before catching a wind current and rising effortlessly into the air. I’ve never seen one land on the water—and I’d love to witness one take off. They’re said to appear as if they’re walking on water when they lift off, which is how they got their name: petrel, a diminutive of Peter, after Saint Peter’s legendary stroll across the Sea of Galilee.
As for the “spectacled” part? That comes from the delicate ring of white feathers around their eyes—giving the impression of a bird wearing glasses.
Brilliant, Brave, and Bonkers
Greg, our onboard naturalist, is quite a character—he’s got a soft spot for anything scaly, slimy, or venomous, and he’s never met a spider or snake he didn’t admire. In his talk, “A Fool to Nature,” he spotlighted the eccentric brilliance of naturalists during the Age of Discovery, pausing occasionally to poke fun at “twitchers” (birders). I left with a new appreciation—and a few jaw-dropping stories—about some wildly committed scientists I’d never heard of before.
George Eberhard Rumphius: The blind botanist of Ambon, he catalogued Indonesia’s flora with unshakable devotion—even after losing his sight, his wife, his daughter, and his life’s work to fire and quake.
Richard Spruce: A quiet Englishman with a spine of steel, he braved 15 years in the Amazon cataloguing mosses, dodging disease, anacondas, and revolution—all for the love of liverworts.
Thomas Edward: A penniless Scottish shoemaker with 11 children and a home bursting with specimens, he once walked into the sea to end it all—only to spot a rare skua, turn back, and chase it for science. Even despair couldn’t compete with a new tick on his bird list.
Constantine Samuel Rafinesque: A polymathic French naturalist who named thousands of species—some real, some possibly imaginary. He once tore through Audubon’s home completely naked, chasing bats with Audubon’s own violin—shattering both instrument and decorum. He named thousands of species, blurring the line between science, dream, and delirium.
Lord Walter Rothschild: A British banker who preferred beasts to banking, he amassed the world’s largest private zoological collection and once rode a zebra-drawn carriage to Buckingham Palace just to prove it could be done. His museum housed 300,000 bird skins, 2.25 million butterflies, and at least one cassowary that chased guests. He refused to marry, preferred birds to people, and ensured that half the animal kingdom bore the names of his friends—or himself.
Frank Buckland: Surgeon, showman, and zoologist with the appetite of a mad emperor, he tried to eat his way through the animal kingdom—roasting crocodiles, nibbling porpoises, and declaring mole “the vilest dish known to man.” If it moved, he studied it; if it didn’t, he probably tasted it.
J.L.B. Smith: South African chemist-turned-ichthyologist who nearly keeled over when a “living fossil” coelacanth landed in his lap—thought extinct for 65 million years. He spent years obsessively chasing a second one, fueled by cigarettes, fish guts, and sheer scientific fervor. When he got hold of one, he was so terrified of losing it that he slept in the same room with the rotting fish—nose be damned, science first.
John Gould: A sharp-eyed ornithologist and even sharper entrepreneur, he set Darwin straight about his finches—and then set about selling birds to the British elite in lavish, hand-colored tomes. With his wife’s artistry and a flair for self-promotion, he turned feathers into fortune and natural history into a status symbol.
Heiko Bleher: A living German ichthyologist who seems to have missed the memo that the Age of Exploration ended, this fish-obsessed thrill-seeker discovered hundreds of freshwater species—often while hacking through jungles, dodging bullets, or contracting exotic illnesses. If it swims in a forgotten river, Bleher’s probably chased it.
Show Me the Way
This afternoon’s navigation workshop introduced us to measuring distance on a nautical chart by hand using a pair of dividers and a Mercator-projection chart. The method is simple and surprisingly satisfying:
Place one tip of the dividers on your starting point and the other on your destination.
Without changing the spacing, move the dividers to the chart’s latitude scale (along the side).
Read off the number of minutes of latitude spanned.
Convert to nautical miles—remember, 1° = 60 nautical miles.
One challenge with this method is maintaining the spacing of the dividers, especially in rough seas. A jostled hand can throw off your measurement.
While this is a practical and time-tested method, it’s not the only way to estimate distance. In the age of sail, navigators often relied on rhumb lines—routes that maintain a constant compass heading. On a Mercator chart, rhumb lines appear as straight lines, but that can be misleading. Though they look shorter than great-circle routes on a flat map, a great-circle path is always the shortest distance between two points on a sphere
Rhumb-line sailing is easier to steer, as it doesn’t require frequent course corrections. In contrast, great-circle navigation demands ongoing adjustments but can reduce the total distance traveled—by up to 15%, depending on latitude.
The manual divider method provides a reasonable approximation for short distances. But for greater accuracy over longer spans, you can calculate distance using the differences in latitude and longitude between two points. With a simple formula—and a calculator or spreadsheet—the computation becomes quick and easy.
Closing Thoughts
As this marvelous day inches toward dinner, I spot a ship on the horizon—a striking sight after so many days surrounded only by sea since we left Inaccessible Island. It disappears as quickly as it came, but its brief appearance reminds me that we’re not alone out here—just scattered points on a vast ocean, charting our own courses.
The naturalists we met today were, in their own way, navigators too. Driven by wonder, obsession, or pure eccentricity, they mapped the unknown—not always efficiently, but always with heart. As we steam toward South Africa, dividers stowed and petrels in our wake, it’s nice to think we’re sailing in the spirit of their curiosity.
“Those who contemplate the beauty of the earth find reserves of strength that will endure as long as life lasts.” —Rachel Carson
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