Survival, Reproductive Success, and Spread of Introduced Rio Grande Turkeys in Northeast Iowa

Thirty-nine Rio Grande wild turkeys (Meleagris gallopavo intermedia) from Texas were introduced in the Yellow River State Forest, Allamakee County, Iowa, in the winter of 1960-61. The population was studied in three northeastern Iowa counties from June, 1966, through September, 1967; concentrated field studies were centered in and near the Paint Creek Unit of the forest. Adult turkeys appeared to tolerate the northeastern Iowa climate well, but poults may not be so tolerant. Although reproduction has occurred each year since the introduction, poult survival seemingly has been sporadic, possibly because of differences in weather conditions during the rearing seasons. Records indicate production was favorable for 1961, 1965, and 1967 compared with 1962, 1963, 1964, and 1966 when it seemed to be less so. The turkey population appeared to be rather stable by the end of the study but probably never has exceeded 100. Nevertheless, each year there has been a progressive extension of the turkeys\u27 known range. Sighting records have shown that the main inhabited turkey range was composed of 71 square miles in 1961, 100 in 1962, 108 in 1963, 139 in 1964, 149 in 1965, 316 in 1966, and 343 in 1966-67. Verified sightings have been made across the Mississippi River in Wisconsin and up to 41 miles from the release area in Iowa