On May 28, 1806, while camped at Weippe Prairie, waiting for the snow-choked Indian trail across the Bitterroot Mountains to thaw out, Meriwether Lewis had time to study and describe this bird with his usual thoroughness, immediately correcting Clark's error as to the bird's taxonomy:
since my arrival here I have killed several birds of the corvus genus of a kind found only in the rocky mountains and their neighbourhood. [it] has a loud squawling note something like the mewing of a cat. the beak of this bird is 1-1/2 inches long, is proportionably large, black and of the form which characterizes this genus. the upper exceeds the under chap [beak; properly, mandible] a little. the head and neck are also proportinably large. the eye full and reather prominent, the iris dark brown and puple black. it is about the size and somewhat the form of the Jaybird tho reather rounder or more full in the body. the tail is four and a half inches in length, composed of 12 feathers nearly the same length. the head neck and body of this bird are of a dove colour. the wings are black exccept the extremities of six large f[e]athers occupying the middle joint of the wing which are white. the under disk of the wing is not of the shining or g[l]ossy black which marks its upper surface. the two feathers in the center of the tail are black as are the two adjacent feathers for half their width the ballance are of a pure white. the feet and legs are black and imbricated with wide scales. the nails are black and remarkably long and sharp, also much curved. it has four toes on each foot of which one is in the rear and three in front. the toes are long particularly that in the rear. This bird feeds on the seed of the pine and also on insects. it resides in the rocky mountains at all seasons of the year, and in many parts is the only bird to be found.
from The Journals of the Expedition Under the Command of Capts. Lewis and Clark