Spring 2001 Whooping Crane Migrational Survey Protocol Implementation Report

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site was in other/barren, 1 use site was in a soy bean field, 1 use site was in lowland grass, and 1 use site habitat type was missing from the dataset. III.B. Distances to visual obstruction >1.5m The visibility in the four directions was not averaged over the use sites because the data contains the value `infinity' as well as missing data (Table 5). Visibility measurements were not taken at use sites without standing water. III.C. Flow The 7 riverine use sites were all located between the Grand Island and Kearney gages (Table 6). The flow during the spring migration season was highly variable within a daily cycle due to management for power generation at the Johnson Power Plant, Central Nebraska Public Power and Irrigation District (Figures 2, 3, 4 and 5). According to Glenn Engle (US Geological Survey, pers. comm.), the provisional record appears to- show ice in the channel at Grand Island for the first part of March (the flows appear too high when compared with flows at Kearney). The mean daily flow will likely be updated for this period. III.D. Substrate All 7 use sites in the wetted channel reported sediment type as coarse sand, between 1 and 4.9 mm. III.E. Unobstructed width Unobstructed width directly measured in the field at each use site in the wetted channel was not measured as described in the protocol. The measurements contained in this report were derived from the measured depth profile data. The average unobstructed width for each transect at each riverine use site is in Table 7. III.F. Water depths The depth profiles for each transect at each riverine use are presented in Figures 6 -11. For each profile, the average water depth was calculated by selecting points along the channel transect every 0.25m and predicting the depth based on linear interpolation between the two adjacent data points measured along the transect (Figure 12, Table 8). For areas of the channel too deep to wade a depth of —4 ft was assigned for calculations of average depth. III.G. Sandbar Elevation The protocol implemented in spring 2001 did not specify that sandbar elevations should be estimated. This parameter was not consistently recorded and cannot be summarized. IV. Searcher Efficiency The objective of the searcher efficiency trials was to estimate the percentage of whooping cranes located by the aerial surveys. Sandhill Crane decoys painted to look like whooping cranes were placed in random locations in the study area. Cooperators placed decoys in the evening, notified the ground crew leader, and retrieved decoys the Spring 2001 Whooping Crane Survey Report 4 11/19/01