May 7 Redwood City San Mateo Co. Caly. big slough with mud banks, spartina, grindelia & salicornia goes right into middle of town, passing gas tank. To filthy, no birds. One heard singing near gas tank but was apparently from garden across street. In middle of town hit willows. Would have been an excellent continuing for song sparrows one if wellenok I didn't look at them - houses & streets everywhere. I covered the slough between Bayline & Ditmer Highway. Heard birds in Redwood City yards. Creek north of Redwood City - No good. 1 pair in willows then 500 or more yds to marsh - couldn't find birds on inside of highway - good small marsh on Bay side in 3-50 yds - rich grindelia, salicornia with some saltgrass spartina along banks - saw possibly one bird. ?? why no more? now singing.