Effectiveness of search patterns for recovery of animal carcasses in relation to pocket gopher infestation control

We tested four search patterns to identify one or more that consistently resulted in the location of a high percentage of above ground carcasses. Searchers found only 25·4% of placed carcasses. The random search pattern exhibited the lowest search efficiency (i.e. percent carcass recovery), 2·6%. This differed significantly from the other three search patterns (E/W transects; E/W transects followed by N/S transects; five randomly placed, 0·027-ha circular plots), which ranged in search efficiency from 24·5 to 36·2%. No significant difference in search efficiency over time was noted, and recovery rates were comparable in the morning and afternoon. Searchers did not differ in mean time spent searching or in carcass recovery efficiency. Carcass density did not influence search efficiency, but searchers found proportionally more carcasses on high carcass density plots. Starlings, the largest and least cryptically colored of the three carcass types, were recovered in the greatest proportion. Carcass degradation by various animals was confirmed to be an important contributor to rapid carcass deterioration. Selecting the best overall search pattern requires careful consideration of a number of factors. Because search efficiency was low regardless of search pattern, a substantial correction factor should be used to estimate the number of carcasses occurring on the surface after a baiting operation.