My professor, Dr. Chuck Yohn, the first professor to insist I address him by his first name, taught me to bird. The class was Vertebrate Zoology and I was living in a the corner of a cabin, in the corner of a peninsula, in the middle of a lake, in the middle of Pennsylvania, and surrounded by wilderness. One road led in and that same road led out. But I didn't have a car, so my road led wherever my feet landed. And with the lake beginning to freeze, my feet wandered in every direction.
I grew up watching feeders and learning what lived under rocks flipped in the stream. Northern Cardinal, House Finch, Two-lined Salamander, Hellgrammite. Now I was being taught taxonomy, niches, and the phenology of migration. Spizella arborea, Catharus guttatus, Pinus pungens, Acer saccharum.
"Hey Chuck! Will I get to see Indigo Buntings this summer?"
"Yeah. You won't be able to swing a dead cat without hitting one of them."
Earlier this week Chuck was teaching us about irruptive winter migrations of finches. Crossbills are dependent on cone-bearing trees like pines, hemlocks, and spruces. The upper and lower bill cross to allow the bird to pry open the cone scales and extract the seed. Which is of course how they got their name: Crossbill. Two species exist in North America, the Red Crossbill and the White-winged Crossbill. When cone crops are abundant, these finches remain in the boreal forest of Canada and New England. But if the cone crop is poor, they'll shift their range south in search of a more reliable food source. As I'd seen so far this winter, a large population of another irruptive finch species, the Pine Siskin, has been constant at the feeders hanging off the back porch of the Shuster Hall.
"Hey Chuck! There are two birds on the feeder with weird bills! They looked like they were crossed. Are those crossbills?"
"Where?! Are they still there?!"
"Nope, they flew off right after I put my binoculars to my glasses."
"Did they have wingbars?"
"Yeah, looked like two white ones."
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