Densities in early summer of one to three adult blue racers per acre probably are typical of the better types of habitat in the region of my study. The upland field area estimated to have 2.82 racers per acre was better habitat than the other two study areas. Prior to 1948 it had been cultivated and severely eroded. In 1949 most of it was sown to seeds of prairie grasses, and by 1958 different parts of it were dominated by different species of native perennial tall grasses interspersed with areas that supported a weedy type of vegetation, and other areas that supported dense thickets of sumac, dogwood, elm saplings, or other woody plants. The abundance and diversity of dense cover and of small animals made this area especially favorable habitat for the racer. Table 23. Captures Recorded and Populations Estimated From Them in Headquarters Field Area of Reservation Column headings: A: 1955 B: 1956 C: 1957 D: 1958 E: 1959 F: 1960 G: 1961 H: Seven-year average ==========================+=====+=====+=====+=====+=====+=====+=====+==== | A | B | C | D | E | F | G | H --------------------------+-----+-----+-----+-----+-----+-----+-----+---- _First Census_: | | | | | | | | May | 11 | 21 | 7 | 24 | 17 | 13 | 6 | 99 June-July-Aug. | 20 | 11 | 25 | 20 | 22 | 12 | 14 | 124 Recaptures | 2 | 1 | 4 | 5 | 5 | 2 | 0 | 19 Estimated population | 110 | 231 | 44 | 96 | 75 | 78 | ... | 92 | | | | | | | | _Second Census_: | | | | | | | | May-June | 18 | 25 | 17 | 28 | 27 | 15 | 13 | 143 July-Aug.-Sept.-Oct | 15 | 8 | 17 | 15 | 15 | 11 | 8 | 89 Recaptures | 4 | 1 | 7 | 5 | 9 | 3 | 1 | 30 Estimated population | 68 | 200 | 41 | 84 | 45 | 55 | 104 | 61 | | | | | | | | _Third Census_: | | | | | | | | May-June-July | 26 | 28 | 22 | 31 | 31 | 20 | 19 | 177 Aug.-Sept.-Oct | 5 | 7 | 13 | 12 | 6 | 5 | 2 | 50 Recaptures | 1 | 2 | 7 | 5 | 3 | 1 | 1 | 20 Estimated population | 130 | 128 | 47 | 87 | 63 | 75 | 148 | 63 | | | | | | | | _Three Sets Combined_: | | | | | | | | Combined first samples | 55 | 74 | 46 | 83 | 75 | 48 | 38 | 419 Combined second samples | 40 | 26 | 55 | 47 | 43 | 28 | 24 | 263 Combined recaptures | 7 | 4 | 18 | 15 | 17 | 6 | 3 | 70 Estimated population | 105 | 160 | 47 | 87 | 63 | 75 | 101 | 75