The explorers actually saw three types of crows during their long journey - the American crow, the northwestern crow, and the common raven.
Capt. Clark, November 29, 1805--The winds are from Such points that we cannot form our Camp So as to prevent the Smoke which is emencely disagreeable, and painful to the eyes. the shore below the point at our camp is formed of butifull pebble of various colours, I observe but fiew birds of the Small kind, great numbers of wild fowls of Various kinds, the large Buzzard with white wings, grey and bald eagle's, largered tailed Hawks, ravens & crows in abundance, the blue Magpie, a Small brown bird which frequents logs & about the roots of trees, Snakes, Lizards, Small bugs, worms, spiders, flyes & insects of different kinds are to be Seen in abundance at this time.
Capt. Lewis, March 5, 1806--The Crow raven and Large Blackbird are the same as those of our country only that the crow is here much smaller yet it's note is the same. I observe no difference either between the hawks of this coast and those of the Atlantic. I have observed the large brown hawk, the small or sparrow hawk, and the hawk of an intermediate size wiht a long tail and blewish coloured wings remarkably swift in flight and very firce. sometimes called in the U'States the hen hawk. these birds seem to be common to every part of this country and the hawks crows & ravens build their nests in great numbers along the high and inaccessable clifts of the Columbia river and it's S.E. branch where we passed along them.