A technique is described for sampling sections of the sky individually during a raptor migration count to obtain an unbiased estimate of the true number of raptors passing. This allows an estimate to be made of the efficiency of raptor detection by an observer counting at the same location and time. Practical and statistical issues are addressed that must be understood for efficient use of the technique.
Sattler, Gene D. and Bart, Jonathan, "A Technique for Evaluating Observer Efficiency in Raptor Migration Counts" (1985). Faculty Publications and Presentations. Paper 40.