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next day. The personnel conducting aerial surveys for AIM did not know the location of <br />the searcher efficiency decoys <br />IV.A.. Details of Detectability Trial Point Selection <br />Forty -five points within the study area were selected as locations for searcher <br />efficiency trials by overlaying systematically placed points on the "accessible" lands in <br />the study area (Appendix F). Accessible lands are defined as the BOR GIS coverage <br />titled land_own.shp and additional properties with known accessibility (i.e., Grand Island <br />Well Field Property). The systematic points were compiled from 414 points placed from <br />0 to 3.5 miles North or South of points (one every '/4 mile) along the main channel <br />(Figure 13) and from 26 points (one every 4 miles) along the main channel of the river <br />for a total of 440 points. The latter set of points was- selected because the TC was <br />concerned that too few points would be in the main channel. Thirty -seven points were <br />identified as "accessible" from the 414 points, and 8 points were identified as <br />"accessible" from the 26 points, respectively (Figure 14). <br />The 45 points were assigned to 5 volunteer cooperators (Jim Jenniges, Paul <br />Tebbel, Dave Carlson, Paul Currier, and Mark Czaplewski) for decoy placement from <br />April 18 to April 30t'. The decoy placement protocol recommended decoys be in place <br />from 6 am to 10 am but did not specify which day the decoys should be placed. Thirty - <br />two of the 45 points were placed by cooperators and are assumed to be a random sample <br />of decoys from the random sample of decoy points. Two of these decoys were removed <br />from the searcher efficiency analysis because the aerial flights did not fly within a mile of <br />the decoy location when the decoy was in place. <br />The aerial flight crews observed 17 decoys. Because the decoy locations sighted <br />by the aerial survey crew were not described with UTM's, there was difficulty in <br />determining which decoys the observers detected. In 2 of the 17 observed decoys, the <br />descriptions of decoy locations by the flight crew could not reliably be connected to . <br />locations of decoys placed in the study area on that day. Three cases could explain the <br />situation: 1) the decoy was in the wrong place, 2) the description of the decoy location <br />provided by the flight crew was wrong, 3) the flight crew observed a whooping crane or <br />other white bird. The two decoys closest to the descriptions were removed from the <br />analysis. <br />IV.B. Spring 2001 Estimates <br />Searcher efficiency estimated following the sampling plan results in study area <br />and channel estimates. The analysis estimates the percentage of the 28 decoys detected <br />by the aerial flights (Table 9). For accessible lands in the entire study area, 47.6% (95% <br />CI: 26.3, 69.0) of the decoys were observed by the aircrew. For the in- channel accessible <br />lands, 71.4% (95% Cl: 38.0, 100.5) of the decoys were observed by the flight crew. If <br />we choose to combine these two samples and estimate searcher efficiency. by land cover <br />class, 80.0% (8 of 10) of the decoys were observed in the channel habitat and 38.9% (7 of <br />18) of the decoys were observed in the upland habitats. Confidence intervals cannot be <br />calculated for these estimates. Estimates of searcher efficiency from this implementation <br />were based on flights at altitudes of 1000 feet and conditions associated with the Spring <br />survey. <br />Spring 2001 Whooping Crane Survey Report <br />11/19/01 <br />