Cogswell 1950 Wilsona pusilla 2 June 24 (cont.) Finally the two flew across the streambed - one immediately returned to side where original chase had been taking place. Both of them then sang - began foraging - each apparently in his own territory now. June 30- Beij Bend, 5750 ft., on S. Fork Yuba R., Placer Co., Calif. - 2 came (a.m.) from aspen + older thickets in shady opening of tall fir + pine forest to join other birds at my owl call. (p.m.) Same result. Both sang at once (i.e. = 2 JS). July 5- 2100-7300 ft., 3/4 mi. W Donner Pass, Placer Co., Calif. - 3 heard July 8} singing in dense chaparral of bitter cherry, manzanita, tobacco brush, + aspen on S-facing slope. There are still some good rivulets draining the area, but it is hardly "riparian". (2 here on 8th) July 5? Cisco Grove, 5650 ft., on S. Fork Yuba R., Placer Co., Calif. ? July 8} 2 heard singing in dense riparian thickets of willow, creek dogwood, + aspen under tall cottonwoods. There were several yellow warblers here also. July 11 near Sugar Bowl Lodge, 7000 ft., 1.2 mi. SSW Donner Pass, Placer Co., Calif. - songs still frequent in willow thickets. July 19 700ft, "Sugar Bowl" (4 mi SE of last) - 2 singing a (early am), few times only, from willow thickets of cold N-facing slope. Those of meadow nearer lodge seem to have largely ceased singing. July 20- calls only, heard in this same spot early m.a.m. July 31 near Sugar Bowl Lodge - 1 giving a subdued song in alder thickets along stream. The species is as free quent in conifers now as in willows; mostly just foragers.