Mar 25 Jewel Lake, 5/10 ft., Contra Costa Co., Calif. is in that area. Looked over area A-C 12x13- no nests there, tho I chased the S pair out of there. -Lake Temescal, 420 ft., Alameda Co., Calif.- The nest at 76.5 has four eggs in it, meaning that two were laid during the night. They were marked #3 & 4. Both SE birds were ready, the male in partial display while I was near the nest, the ♀ showed less demonstration than the ♂. While I was at the nest I could hear- (just now a male giving “pukh-puk pukh-puk pukh-wh, whk, whk”; in partially display, that is head a little lowered, tail elevated as it faced and swam from -I 11 towards I 9).- another pair over near H6 making some low noises (“punk-ruk” etc). -A rather severe battle at F15-16- a pair chasing, with considerable splattering c-2 other birds, to H17. The male crowed “Kuk-Kuk-kuk” 3 times, before it turned S again. This bird was displaying as it crowed. ♂A bird came over to the nest at P16.2, climbed on it, it nearly sank, and stood for a moment plapping one foot on the nest, then slapped the other one. Finally, after some greening in left, swimming off to beyond P24. Counted at least 11, and figure there are at least 4 more unseen today. Saw ♂.