Yellow-billed Cuckoo Coccyzus americanus July 8 Sacramento R., 4 mi. n. of Glenn, Glenn Co., Calif: 3. Two on David Gaines Am. Birds Breeding Bird Census plot and one about 1/4 mile to the north. We got good looks at two of the birds. The most frequent call was a mournful coo-ing which was very similar to that of the Roadrunner. The guttural call was very ventriloqual, and the bird inflated its entire gular region to make the sound. The distinctive series of "coups" was also heard, but less frequently. Dave said most foraging is done in disturbed second growth (willow + cottonwoods) but that the nest may be in more mature riparian forest; habitat requirements appear to be wet areas + willow thickets - mature forest not necessary. Seasonal flooding necessary to maintain the disturbed nature of the habitat. The birds appeared mildly interested in tape-recorded cuckoo "coups" (Dave said their interest had waned with time), but one responded fairly vigorously to my whistled imitation of the cooing, coming to within 40'. This was the first time I'd seen this species in Calif.