Survival Rates for Northern Bobwhites on Two Areas with Different Levels of Harvest

We estimated survival rates for radio-marked northern bobwhites ( Colinus virginianus) in south-central Iowa from I 984 to I 988. Survival rates and survival functions were calculated for 2 areas that received different and varied amounts of hunting pressure. Survival from fall-spring averaged 17.1 % ± 6.9% on the Brown\u27s Slough study area (BSSA) and 20.1 % ± 5.7% on the Millerton study area (MSA). Although these estimates were not different (P = 0.898), the survival functions did differ between the 2 areas (x2 = 25.82, P\u3c0.001). Mortality due to hunting averaged 27.7% ± 8.2% on the BSSA during the fall-spring period and 12.3% ± 4.9% on the MSA. Predators accounted for 52% of fall-spring mortality on the BSSA and 79% of the mortality on the MSA. The BSSA had much lower rates of predation the 2 months following the hunting season. Survival rates during both the spring-fall period and annually did not differ between the 2 areas (P = 0.395 and P = 0.979). Hunting did not appear to be a limiting factor for quail numbers on these areas during the study

Breeding Strategies of the Northern Bobwhite in Marginal Habitat

We studied nesting behavior of radio-tagged northern bobwhite (Colinus virginianus) in south-central Iowa from 1984 to 1988. Female bobwhite incubated 78% of81 clutches where incubation was observed and males incubated 22%. On only 1 occasion were both a male and female observed to incubate the same clutch. Incubation was initiated on 73% of the nests by females before 1 July, while incubation was initiated on 56% of the clutches by males after 1 July. Males hatched 16% of all clutches, first nests by females accounted for 69%, renests for 4%, and second clutches by females that had already hatched 1 clutch for 11 %. Chicks from 3 of the first broods of females that hatched ~l brood survived for ~l week and were not accompanied by other adults. These breeding strategies appear to provide bobwhite populations multiple chances at recruitment in variable environments

Survival Rates of Northern Bobwhite Chicks in South-Central Iowa

We estimated survival rates for radio-tagged northern bobwhite quail chicks (Colinus virginianus) in south-central Iowa from 1986 to 1988. Survival rates and survival functions were calculated for chicks from broods raised by females, broods raised by males and from broods that did not have an adult associated with them. Survival functions differed between broods with hens and those without adults. Predators accounted for almost all of the observed mortality

Results of the August Roadside Survey for Upland Wildlife in Iowa: 1963-1988

Results of the August roadside survey collected from 1963 through 1988 were examined to determine if trends could be detected in the counts of ring-necked pheasants (Phasianus colchicus), northern bobwhite (Colinus virginianus), gray partridge (Perdix perdix), cottontail rabbits (Sylvilagus floridanus), and white-tailed jackrabbits (Lepus townsendii). The counts also were compared to harvest estimates co determine if correlations exist. Statistically significant linear trends were detected statewide for pheasants, gray partridge and jackrabbits during the 1963 co 1988 period. Trends were downward for all species except gray partridge. During the late 12 years (1977 through 1988), the only significant trend detected was for gray partridge, where counts increased. The survey results also were examined for trends on a regional basis where possible. Significant correlations were found between the mean counts and harvest for all species. For cottontails, however, chis relationship appears to have changed as the correlation of the counts with harvest since 1977 is near zero

Influence of Simulated Harvest on Iowa Wild Turkey Populations

Computer models were used to simulate autumn harvest of a wild turkey (Meleagris gallopava silvestrus) population in Iowa. Parameters were based on estimates of survival rates, fecundity rates, and age and sex ratios from field studies in mixed forest-farmland from 1977 to 1981. Simulations with average survival and fecundity parameters resulted in a population growth rate of 4% per year. If female survival rates were reduced 4.8% or fecundity was reduced 13.9%, the population became stationary. Interaction of hunting and non-hunting mortality was incorporated according to 3 hypotheses: additive, completely compensatory, and compensatory mortality rates up to a threshold. Estimated allowable autumn harvest rates, based on the goal of a stationary breeding population, ranged from 4.7% to 9.5 % of the females and from 14.8% to 28.4% of the males. At these harvest levels, female survival would have to increase approximately 5% and fecundity 16% to compensate for the harvest and return the population to former growth rates. The time required for the total population to decline by 25% of present levels ranged from more than 100 years at 5% harvest rate under additive mortality to almost 74 years at 10% harvest rate under the threshold theory