Simultaneous use of mark-recapture and radiotelemetry to estimate survival, movement, and capture rates

Biologists often estimate separate survival and movement rates from radiote lemetry and, mark-recapture data from the same study population. We describ e a method for combining these data types in a single model to obtain joint , potentially less biased estimates of survival anti movement that use all available data. We furnish an example using wood thrushes (Hylocichla muste lina) captured at the Piedmont National Wildlife Refuge in central Georgia in 1996. Thr model structure allows estimation of survival anti capture pro babilities, as well as estimation of movements away from and into the study area. In addition, the model structure provides many possibilities for hyp othesis testing. Using tie combined model structure, we estimated that week ly survival of wood thrushes was 0.989 +/- 0.007 (+/-SE). Survival rates of banded and radiomarked individual; were not different (<(alpha)over cap>[S -radiocd, S-handed] = log[(S) over cap(radiocd)/(S) over cap(banded)] = 0.0 239, 95% CI = -0.0196 to 0.0486). Fidelity rates (weekly probability of rem aining in a stratum) did. not differ between geographic strata (psi = 0.911 +/- 0.020; <(alpha)over cap>[psi(11), psi(22)] = 0.0161, 95% CI = -0.0309 to 0.0631), and recapture rates (p = 0.097 +/- 0.016) of banded and radioma rked individuals were not different (<(alpha)over cap>[p(radiocd), p(handed )] = 0.145, 95% CI = -0.510 to 0.800). Combining these data types in a comm on model resulted in more precise estimates of movement and recapture rates than separate estimation, but ability to detect stratum or mark-specific d ifferences in parameters was weak. We conducted simulation trials to invest igate the effects of varying study designs on parameter accuracy and statis tical power to detect important differences. Parameter accuracy was high (r elative bias [RBIAS] <2%) and confidence interval coverage close to nominal , except for survival estimates of banded birds for the "off study area" st ratum, which were negatively biased (RBIAS -7 to -15%) when sample sizes we re small (5-10 banded or radioed animals "released" per time interval). To provide adequate data for useful inference from this model, study designs s hould seek a minimum of 25 animals of each marking type observed (marked or observed via telemetry) in each time period and geographic stratum.