On 9 January 1972, while studying a concentration of shorebirds at the mouth of the Salinas River, Monterey County, my attention was attracted by a flock of approximately 30 swallows feeding over the water well offshore. At first glance these appeared to be Tree Swallows (Iridoprocne bicolor) and Violet-green Swallows (Tachycineta thalassina) in equal number, but as I watched them, a Rough-winged Swallow (Stelgidopteryx ruficollis) suddenly appeared. In characteristic fashion it enabled me to watch it, approaching within 50 feet of me, then temporarily going out of sight as it mingled with the other swallows, only to reappear again from the middle of the river. Under these circumstances there was no question as to its identity, but had it been possible I would have collected it in order to determine the race. I spent the better part of an hour hoping it would feed, even briefly, over the marsh in which I was standing, but it never did.