May 17 Lake Tamescol 420 ft., Alameda Co., Calif.- left at J8 to preen. ♀ SW birds(or?) was preening at I 7.3, the ♂ Ruddy cut back into the cat willows of I 8. 24 which is on the dividing line between the two S territories. 2:30 p.m. as the SE ♂ crossed from L7 to K6, the ♀ on the nest "punk-runkled" several times. But he kept going, on to L 4. 2:34 - SE ♀ on nest is "punkzing" as a ♀ Mallard w/brood of 2 small yng lingeres a few feet out from the nest. 2:36-some bird just closed W/SE from near the island to J17. It was a W bird. ♂(♀ ?). 2:42 - SE ♀ off the nest, meet her mate at J8 and went on to platform there. he chasing, coughing, she "cackling"; she mounted him and intromission may have occured but it is doubtful. They both got off the platform, she dived, and by 2:45 p.m. he was settled on the nest. The M♂ in K7 was "punking" thru the whole affair. I wonder if the M♂ is keeping the SE ♂ in a copulatory state of mind by all her antics, but his & monogamous nature prevents copulation with her, so he vents his desires on the SE ♀ when ever an exchange is made, or at least tries nearly every time. Shortly before 2:42 a W bird was at F10.9 with one yng. W♂ at G/5 was in a threatening attitude, but did and