Whooping Crane Migrational Habitat Use Draft (2)

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Movement Pattern Summary The average distance moved across the 13 crane groups was 3.22 miles (95% CI: 0.10, 6.34) with the minimum of 0.49 miles and the maximum of 21.64 miles. Movement patterns of each crane group are shown in figures 4 through 15. Trends in the Index of Use The index of crane use was calculated for each monitoring season (Table 8). The systematic surveys resulted in 1168 flights that were completely flown. The 6% of the flights which were incomplete were not used to avoid the bias associated with uneven coverage of the study area in the east-west direction. The estimate of the annual change in the index of use for whooping cranes in the study area was -0.0008 (95% CI: -0.0286, 0.0269). This estimate was not significantly different from zero (p=0.9547). The estimate of the annual change in the adjusted index of use for whooping crane in the study area was -0.0057 (95% CI: -0.0507, 0.0393). This estimate was not significantly different from zero (p=0.8042). The negative trend for each index is shown in Figure 16. The winter peak count of the Aransas-Wood Buffalo population increased throughout the Cooperative Agreement period and was not a significant covariate in the model (Figure 17). Activity Summary Feeding behaviors were the most common activity observed during crane group monitoring in the spring and fall and for both seasons combined. Crane groups spent an average 73% of the observed period (95% CI: 63, 82) feeding in the spring while they spent 69% of the observed period feeding (95% CI: 62, 76) in the fall (Table 9). The second most commonly observed activity was resting, crane groups spent 15% of the observation period resting in the spring (95% CI: 5, 24) and 9% of the observed period (95% CI: 5, 14) was spent resting in the fall. Alert and preening activities were fairly uncommon, crane groups spent 7% of the observation period (95% CI: 2, 11) alert in the spring and 11% of the observed period (95% CI: 3, 19) was spent alert in the fall. Crane groups spent 3% of the observation period (95% CI: 1, 5) preening in the spring and 10% of the observation period (95% CI: 5, 15) was spent preening in the fall. Courtship and defensive behaviors were very rare, less than 2% of the time, and only observed in the spring. These results are based on observations made by ground crews and observations are limited to diurnal activities. Habitat Selection Means were estimated for each land cover habitat parameter for the channel, upland, and for the study area combined with the systematic observations (Table 10). Some variables had significantly different values when the means were calculated including opportunistic observations. We chose to report the means based on the systematic sample because they are an unbiased representation for the population of interest. Opportunistic observations are spatially biased because they were obtained with an unknown detection probability and an unknown level of effort. Means estimated from the combined systematic and opportunistic samples are in Appendix B. 11