Nesting Ecology of the Ring-necked Pheasant in Eastern South Dakota

Nesting of the ring-necked pheasant (Phasianus colchicus) was studied in 1973 and 1974 and 90 randomly chosen 4.05 – ha plots in the Lake Sinai Township of south-western Brookings County. Nest initiation and hatching peaks over the 2-year period occurred from 1-15 may and 16-30 June, respectively. Average density of nests was 0.3 per hectare in 1973 and 0.2 in 1974. Average clutch size for combined years was 8.6 for all nests and 10.8 for nests where clutches hatched. Clutch sizes declines as the nesting season progressed. Fertility of eggs in nests where clutches hatched was 96 percent. Hatching success varied between years with 21 percent of 111 clutches in nests hatching in 1973 and 28 percent of 75 clutches in nests hatching in 1974. Fifty percent of the nests in 1973 and 65 percent in 1974 were destroyed while 28 percent and 7 percent of the nests were abandoned in 1973 and 1974, respectively. Highest densities of nests per hectare for cover types as averaged over both years were found in tame hay, 2.19, and roadside, 2.13, while lowest nest densities occurred in pasture, 0.12; flax, 0.13; and small grain, 0.14. Highest hatching success for clutches in nests in the various cover types as averaged over both years occurred in flax, 100 percent, and shelterbelt, 50 percent. Lowest hatching success occurred in alfalfa, 8 percent, and fencerow and pasture, each with 7 percent. Approximately 34 percent of the total nests with hatched clutches was found in idle farmland while roadside and small grains each contained 14 percent. Chi square analysis showed no significant relationship between nest success and cover conditions, amount of dead vegetation at nest sites, height of vegetation, physiognomy of the nest, or shape of the plot. Two major causes of nest failure during the 1973 and 1974 nesting seasons were predation and agricultural machinery. Rate of predation was difficult to estimate since many nests destroyed by predators may have been inactive or abandoned when destroyed. Mammals were associated with 51 percent of all nest failures on sample plots during the study period. Thirty-five percent of the clutches in nests destroyed by mammals showed evidence of incubation while the remaining percentage associated with mammalian predation included abandoned nests, active nests in the pre-incubation period, and nests of unknown category. Losses to machinery on sample plots in harvested crops accounted for 17 percent of all unsuccessful nests each year. Agricultural machinery was a major cause of nest loss in alfalfa as mowing occurred just prior to peak hatching each year. Sixty-nine percent of all nests located in fields of alfalfa but not included within the sample plots during 1973 and 1974 were destroyed by mowing. Losses to machinery in small grains and flax were considerably lower due to later dates of harvesting