Oct. 31 Pitahaya, 40 km. SE Guaymas, 100 feet, Sonora. southwestwardly, and returns from the same direction just before dark. Tonight's return flight was appreciably larger than that of the previous evenings. We have observed an almost daily increase in the number of shore birds on the slough, but many of them have passed unidentified. Most of them are out in the middle of the slough, feeding in shallow water, and approach through the slushy water-covered margin is not feasible. Nov. 1 This morning I crossed over to the north side of the slough and hunted east of the railroad tracks. Here the mesquite was much better developed, the upland vegetation being made up mainly of mesquite trees as high as 10-14 feet, spaced so that their peripheries were several yards apart. Between the trees grasses were of at least two genera the dominant ground cover. Additionally, there were scattered cacti and shrub thickets of the kind prevalent along the south shore, northwest of Camp. Dickers, House finches, refous-winged sparrows, and pyrshuloxias were more abundant here then in the sparser, more cactus dominated scrub south of camp. Today I realized that we have been collecting either two migrant spizellids or, what seems less likely,