Mayhew 1950 April 2 Conaway Ranch, 2 miles east of Woodland, Yolo Co., Calif. greatest concentration of pairs appeared & be in the ditches at the edge of grain fields in sections 7, 27, & 28. A number of the pairs held so tight & the territory that a car driving by them did not make fly. Others, however, took off as soon as a car came near, but usually circled the area at quite a distance. Nine pair returned to their territories almost immediately, apparently, because I had to retrace my route on 2 different occasions, & each time, all of the pairs that had been flushed were flushed a second time from the same spots. In almost every case, the ♀ was the first to fly, followed by the ♂. The ♂ seemed to be aware of leaving the territory, but always followed the ♀. At no time today did I see any ♂ have to defend his territory. It appeared to me that there is more than enough room for territories for all the mallards that are present on the ranch without any need for overcrowding. April 4 Today I counted breeding pairs on all the land from the ranch headquarters north of the River Road. Then I covered all the territory east of