It’s the time of year when migrants come through the banding station on their way from their breeding grounds in the north to their wintering grounds in the south. We see a greater variety of species now—not just those who like to breed here, but everyone who thinks our patch of forest looks like a good place to stop for a snack. It isn’t just that these are different species, though: these birds have a different feel to them. These are travelers on a genuinely long and perilous journey. We banders are, I hope, just a blip in any bird’s day—a frightening moment to be shaken off by mid-afternoon—but the days we interrupt for these migrating birds are epic days.
This is physically manifested, on the birds, as fat.
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.
You would think an embryo in an egg could relax. They can’t eat, or go anywhere; what can the world ask of them, besides that they grow? A decade ago it would have seemed ridiculous to talk about “embryo behavior.” Now, though, we know that even embryos have things to do.
It’s almost a pity that we introduce children to caterpillars so young. The magic of the transformation of a squishy, unimpressive tube into a living, fluttering creature apparently made of stained glass gets muddled up with the rest of the magic of childhood and is too easy to forget when we grow up. Everyone knows about caterpillars turning into butterflies, but almost no one really thinks about it.
Even before they turning into butterflies (or moths), caterpillars are impressive. They hatch tiny, into a bird-eat-caterpillar world, and their one crucial job is to grow big in time to metamorphose. This isn’t a particularly complex task—there’s a reason caterpillars are basically just digestive systems on legs—but it isn’t necessarily easy, either. They need to find the right food and eat it quickly without being eaten themselves.
Every scientist has a few favorite science stories: those papers or sets of papers that we read early in our careers and then reread often, that we think of when we imagine our own ideal research program. One of mine—not exactly a hidden gem, as it’s in all the textbooks now, and is the subject of a very good general-audience book, The Beak of the Finch—is the Grants’ work on Galápagos finches. Peter and Rosemary Grant have spent decades documenting how bill size and shape in these finches fluctuates as rainy years and droughts change the food available on their small island. It’s as complete a picture of evolution in real time as anyone has ever drawn, and a powerful argument for predictable rules (like “bills must be the right size to open the seeds that are available”) leading to unpredictable outcomes in the complexity of a natural system. It’s beautiful.
I wanted to see if I could see similar patterns in the juncos. Like the finches, juncos are primarily seed-eaters. Unlike the finches, the juncos are not neatly contained on a small island; and unlike the Grants, I did not have 30 years to study them. Fortunately, I work in a museum, which is basically a biological time machine. Want to know what junco bills looked like in 1915? No problem!
Thus my time communing with the long-dead feathered denizens of the specimen drawers. Where the Grants had had to live through the decades of data they acquired, I took a shortcut.
Like all shortcuts, however, there were some downsides. I did not get to live in the Galápagos. Also, I was very limited in which juncos I could measure: I might be interested in juncos from a certain mountain range, but if a junco from that range hadn’t been stuffed and placed in a drawer 70 years ago, I was out of luck.
This is a chicken. Its long-ago ancestors were the dinosaurs we now depict as cheap plastic children’s toys in a futile attempt to downplay their ferociousness. The chicken traded those gnashing teeth for a beak, but it still has its forebears’ claws for ripping and disemboweling.
I guess what I’m trying to say is: Whole Foods, your terminology is incorrect.
Baby panda bears have paws. Dinosaurs do not.