Grassland habitat and reproductive success of ring-necked pheasants in northern Iowa

We used radio telemetry from 1990-1994 to compare reproduction of 185 female pheasants in a diverse landscape with 25% perennial grassland habitat in Pale Alto County, Iowa, with that of 72 pheasants on an intensively farmed landscape with 9% grassland in Kossuth County, Iowa. Median dates of the beginning of incubation of first nests were almost identical on the areas, hut median incubation date of renests was earlier at Pale Alto (22 June) than at Kossuth (5 July). Mean clutch size in first nests was 12.6 eggs, which was greater than clutch size of 9.9 for renesting attempts. Success of first nests was 57.3% at Pale Alto and 44.8% at Kossuth, whereas success of renests was 45.6% at Pale Alto but only 26.9% at Kossuth. Linear logistic regression revealed that nest success averaged 62.3% in undisturbed blocks of habitat such as CRF versus 44.8% in small, linear, or disturbed habitats, regardless of the study landscape. Hen success averaged 70.6% at Pale Alto and 52.2% at Kossuth, and it varied more among years at Kossuth. Pheasant nest success was higher in a diversified agricultural landscape with large blocks of undisturbed habitat. When nesting is restricted to small or disturbed habitat fragments pheasant reproduction is probably reduced enough to limit the potential rate of population increase.