Validating the assumptions of the Mayfield method

We tested the assumptions of thr Mayfield method (Mayfield 1975) using 416 Wood Thrush (Hylocichla mustelina) nests monitored from 1993-1997 in the Gr eat Smoky Mountains National Park. We tested for differences in nest surviv al throughout the breeding season and throughout the: nesting cycle. We com pared the Mayfield cumulative survival curve with a modified version of the Kaplan-Meier with staggered entry. In addition, we compared the group of n ests found during nest initiation with those found later in the nesting cyc le. There was no evidence nest survival varied through the breeding season or with different stages of the nesting cycle. Furthermore, the Kaplan-Meie r survival curve agreed with the Mayfield calculation. We found no evidence of heterogeneity. Validation of Mayfield assumptions is important because the method is widely used, allows for statistical comparisons, and is criti cal for estimating seasonal fecundity in bird populations.