Survival of Northern Bobwhite Chicks in Western Oklahoma

Abstract

We estimated survival for chicks within 59 northern bobwhite (Colinus virginianus) broods using a modification of the Mayfield method that allows for brood mixing and intrabrood dependence. Broods were monitored during 1992-94 on the Packsaddle wildlife Management Area in western Oklahoma. Daily survival rates (DSR) were calculated for chicks reared by both female and male parents, chicks from hatching to 20 days old, chicks from 21 to 39 days old, chicks from hatching to 39 days old, by year, and pooled over years. Survival rates of brood mates were dependent on each other (P < 0.0001); therefore, the entire brood was the appropriate sampling unit for estimating variation associated with chick survival. Daily survival rate estimates for chicks in broods raised by females and males did not differ. Daily survival rates of chicks ≤20 days old were not significantly less than DSRs of chicks ≥21 days old. No differences were observed among years for DSR of chicks pooled over sexes ≤20 days old or chicks ≥21 days old (P = 0.9997). Chick DSR pooled over the entire brood-rearing period (x = 39 days, SE = 4.1 days) did not differ among years for either sex or pooled over sexes. Survival estimates pooled over sex and years for chicks from hatching to 20 days old and from 21 to 39 days old were 37.9 and 96.8%. The estimate of chick survival pooled over sex and years from hatching to 39 days was 36.7%.