Survival and reproductive biology of the Bachman's Sparrow

We estimated breeding season survival rates and nest success for Bachman's Sparrows at the Savannah River Site, South Carolina, using radio telemetry. The 1995 breeding season (2 May-9 Aug) survival rate was 0.905 (95% C. I. 0.779-1.03) with 2 mortalities out of 20 individuals. The 1996 breeding season (10 May-25 Jul) survival rate was 0.882 (95% C. I. 0.729-1.04) with 2 mortalities out of 18 individuals. No significant differences in survival rates were detected between years, sexes, or habitat types. The overall breeding season survival rate was 0.893 (95%, C. I. 0.794-0.992). Daily nest survival rate in 1995 was 0.952 (0.013 SE N=26) and 0.889 (0.027 SE N=15) in 1996. Daily nest survival was significantly greater during 1995, with only 1 of 15 nests fledging a single individual in 1996. Nests attempts initiated before 15 June (0.975 [0.012], N=15) had higher survival rates than later nest attempts (0.914 [0.029] N=11, C2=3.77, 1 df, P=0.05).