This is the memory palace. I'm Nate Demet.

1347 birds in drawers and boxes, dead and labeled with paper ID tags tied to their thin

ankles. They are horned larks and grasshopper sparrows, field sparrows, red-headed woodpeckers

and eastern tohies. The oldest of these, two tohies, black-winged and black-hooded with red

brown feathers flanking their white bellies. In the lark, a brown speckled male with streaks

of bright yellow framing its face. Have been in storage in natural history museums since

1880. Lank flat, wings enfolded, chins up, beaks up, legs stretched out, looking like each could

be thrown like a dart. Specimen tags trailing behind like a banner from a plane circling over a

beach on the summer's day. The rest were collected in various fields and forests and town greens

and nature preserves in at least one shopping mall over the course of the falling 135 years.

Then a few years back, a couple of PhD students, Shane Dubra and evolutionary biologist and

Carl Fuldner, a photographer and art historian, opened up those drawers and boxes where those

birds were collecting dust. And I mean that metaphorically, these were well-capped museum specimens.

And the two men started collecting dust. And I mean that literally.

Their theory, and it was a good one, was that those five specific species of birds

could tell them about air pollution in five states between 1880 and 2015. Each of those species

has white bellies that can become discolored by soot and other particulates. Further, at least once

a year each of the species' molds and grows a new set of feathers. So if you looked at say specimen

116522, a female horned lark collected at Getterspond in Ann Arbor, Michigan in 1949.

You know that the soot that still clings to that dead bird, that blackens her white feathers like

the face of a chimney sweep. Dates to 1949. So some of the black carbon put into the air by a

coal plant outside Gary Indiana in 1899, or a smelting factory on the Allegheny in 1922,

...