Cogswell 1950 Tachycineta thalassina 2 Aug. 5 (at dusk) Floriston, 5300 ft., on Truckee R., Nevada Co., Calif. Many of this sp. present among numerous swallows flying up & down over & near the river, here in "Truckee Canyon". Aug. 7 E. side Boca Res., 5600 ft., Nevada Co., Calif. - at least 1 Violet-green flying with several Tree Swallows & many Cliffs. Aug. 21 Brosser Cr., 5650 ft., 1 1/3 mi. E, 3 1/2 mi. N Truckee, Nevada Co., Calif. - A flock of about 10 passed over in nearly a straight SWward course, crossing the valley rather than following it. I would judge them, therefore, to be actually migrating. They flew below tree-top height.