"My Life in Bicycles," a New York Times op-ed essay from Jennifer Finney Boylan, is a charming if slight account of, yes, a life filled with bicycles. Its most vivid passage describes the color of bird poop.

In the Kennebec Highlands, on my mountain bike, I pedal past Kidder Pond, up to the blueberry barrens high atop Vienna Mountain. From there, I watch bald eagles and ospreys, and other birds, whose poop, owing to their diet of berries, stains the gray rocks purple.

A previous version of the article credited the purple poop to the ospreys and eagles, which, it turns out, defecate in unremarkable white. The Times regrets the error:

Correction: August 20, 2014

An Op-Ed essay on Monday described bald eagles and ospreys incorrectly. They eat fish, and their poop is white; they do not eat berries and excrete purple feces. (Other birds, like American robins, Eurasian starlings and cedar waxwings, do.)