Winter censuses on 125 acres of typical farmland in the Thames Valley near Oxford were taken between 1926 and 1935 by means of a line of several observers systematically covering the entire area, sometimes 3 or more times per month. The summer population was determined by marking the location of resident birds on a map on each of 2-4 surveys over the area. The winter population varied from 3.6 to 5 birds per acre, with those species occurring in hedges fluctuating least in numbers and those occurring in flocks on cultivated land fluctuating the most. Summer censuses were obtained from 1931 to 1934, inclusive, on 300 acres of the same farm and averaged about 2 birds per acre. Compared with winter, the summer population was about one-half the size and was everywhere more constant from year to year.