I feel almost disloyal, saying it, but here goes: I’m working on a new project. A non-junco project.
Not that I’ve stopped working on juncos. When we teach science, we tell students “Science is never finished”—true in the larger sense that science is always testing new hypotheses, refining old theories, and correcting erroneous ideas; but also true in the sense that we scientists pretty much never stop doing things once we start them. I’m still analyzing data on the juncos.
But I’m now also generating data on tuco-tucos.
The noble tuco-tuco, a subterranean South American rodent.
Male Common Yellowthroat, a frequent visitor at the banding station.
Unusually heavy rains have put much of the banding station underwater for the past three months. One side effect of this is that, on the days when the area is sufficiently dried out for us to squelch out in our rubber boots and band birds, the mud shows the tracks of everyone else who has been out there before us.
Usually the denizens of the banding station of whom I am aware are the birds we catch in the nets and band. These tend to be small- to medium-sized songbirds. The mud reveals an entirely different set of creatures living in the area.
Raccoon hand prints near a human bootprint.
For birds, cleanliness is not optional. They rely on their feathers for flight and insulation, and only replace those feathers once or twice each year. In between molts, they need to keep their feathers as whole as possible.
Feathers, like our hair, are made of protein; and like all organic things, they degrade over time. Sunlight hastens this degradation, but certain aspects of the feathers themselves can slow it: dark feathers colored with melanin last longer in sunlight, for example. Of more concern, though, are the many creepy-crawly things that like to eat protein, and will happily hang out in a bird’s feathers, munching and laying eggs.
To combat these parasites, birds coat their feathers in protective oil from the preen gland located at the base of their tail, and they bathe.
But they have to be careful. Small wild birds are lunch for everything from feral cats to Cooper’s Hawks, and no bird wants one of these sneaking up on it while it is obliviously scrubbing behind its ears. So they bathe in bursts, a plunge into the water followed by a quick look around.
Did anybody see that?
Planet Earth II, the new BBC documentary narrated by Supreme Voice of Nature Sir David Attenborough, devotes one of its six episodes to animals living in cities. It’s unsurprisingly great. (Even if the ultimate masters of urban living, pigeons, who you might expect to be celebrated in this context, instead spend the episode getting unceremoniously eaten.) The “Cities” episode has to walk a delicate line, heralding animals’ ability to adapt to human landscapes without failing to acknowledge that humans overwhelmingly destroy habitat rather than creating it. It mostly leans to the optimistic side of the line; one segment makes New York City seem like a wildlife paradise.
The darker side of cities is represented by a segment on hatchling sea turtles. The turtles use the shine of moonlight on water to guide them from their nest in the sand into the ocean. Unfortunately, we humans love to shine lights even brighter than the moon, and more than half of the tiny turtles are drawn away from the ocean by the city’s lights.
A hatchling Hawksbill sea turtle in Planet Earth II.
As Attenborough narrates, footage rolls of the baby sea turtles gamely clambering across sidewalks and onto busy streets, heading for the ocean that isn’t there. The bodies of roadkilled turtles are visible in the background. One turtle makes it across the street, then tumbles halfway into a storm grate and gets stuck, lost to view save for one forlornly-waving flipper.
As soon as the episode ended, I began typing into Google: “planet earth 2 did”—at which point Google helpfully autocompleted the rest of the sentence: “planet earth 2 did they help the turtles“. Everyone else who had seen the episode wanted to know, too.
Like elephants or dinosaurs, male Northern elephant seals on land are massive past the point of useful reference. A 5000-lb animal falls off our everyday mental scale; it’s just enormous.
Yet, lounging around on the sand at this time of year—their mating season—these beasts look like they need some band-aids and Neosporin. Their thick, strong hide is marred with new gashes laid over old scars. Titans they may be, but even titans can fall when they square off against other titans.
Two males facing off. The male on the left has blood on his nose.
Nothing better demonstrates the axiom “familiarity breeds contempt” than the pigeon. Pigeons have remarkable navigation skills and are extremely powerful fliers. They perform courtship dances and mate for life (as much as any bird does, anyway). Both parents care for the chicks. They have an adaptation—”crop milk,” a substance that they produce and feed to their chicks, similar in concept (if not physiology) to how we mammals produce milk for our babies—that allows them to breed in habitats most birds could never hope to raise a family in. They thrive in urban environments, making them probably the first and most-often seen wild animal of many city-dwellers. They recognize each other as individuals. They are smarter than you think.
Concerning their usefulness to humans, pigeons are easily raised in captivity and edible. They have been bred into many domestic varieties with strange attributes, such as the propensity to roll over in mid-air. Charles Darwin studied domestic pigeons extensively, and they contributed to the formation of his theory of evolution by natural selection. They have been important message carriers in wartime; pigeons have received the Dickin Medal—like the Medal of Honor, but for animals—32 times, more than any other species (dogs are closing in with 31 medals).
And they come in sparkly colors with crazy eyes.
“Rats with wings,” people say—patently untrue: you can’t get plague from pigeons. “Dirty,” people call them; as if it isn’t our dirt they are wearing, and yet thriving anyhow.
One of the joys of biology lies in appreciating how strange and varied the world is. When humanity starts to feel claustrophobic, you can imagine the life of an albatross, aloft over the ocean for most of her life, searching out schools of delicious fish by their scent; or a cuttlefish, flashing colored signals at his companions as he shoots through the currents, flexible tentacles waving. When the world feels narrow and limiting, you can remember that clownfish change sexes depending on their place in the dominance hierarchy, with males becoming female when they advance to the position of top dog.
Yet—amazingly—biology used to be even wilder. Before satellite tracking and genetic analysis, before “biology” was a recognized science at all, natural philosophers looked at a perplexing natural world and invented some truly outside-the-box explanations for what they saw.
Some of these are fairly well known: for example, the idea that there is a “homunculus”—a tiny human—inside the head of each human sperm cell.
To be fair, we now know that sperm (and eggs, etc.) contain the genetic blueprint for building a human, which isn’t all that far off from containing a tiny human.
But my favorite old science myth involves—of course!—birds.