Eulica Americana Feb 9 Jewel Sale, 510 ft., Tilden Park, Contra Costa Co., Calif. Ducks showed a great deal of concern but the costs gave none. Once the two birds of the S pair were billing and bowing and nibbling near H14. I worked over the area M-Q 24-25 and LMN 21,22,23 looking for any sign of a platform constructed by costs but found no definite evidence. Several rafts of material were seen, all evidently of natural origin, some showing signs of animal use but no evidence of construction activity. While I was working in that north end all the costs moved down to the S end. Several instances of combat were observed, mostly charging but once a display was given. A bird that I believe to be a male charged one bird but did not hotly press the attack, rather displaying, immediately its mate came out from F9, crossed to C11, passing close to but ignoring the displaying bird and attached one of two birds behind the cat-tails there, driving it out to E 12. Territory defense is progressing but not very strictly. I have seen no evidence of aggressiveness against any thing but costs. Some times the ducks are in the way and have to hurry to keep from being trampled, but I have not yet seen a duck attacked directly. Feb 11 Ullin Calif Campus Alameda Co., Calif. X16 tax directly up to W4, bowed, and