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Objective 1: Comparing the Two Survey Methods Methods: Isolated all 6 minute recorded standard surveys (172 in total) Use “recognizers” to automatically.

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Presentation on theme: "Objective 1: Comparing the Two Survey Methods Methods: Isolated all 6 minute recorded standard surveys (172 in total) Use “recognizers” to automatically."— Presentation transcript:

1 Objective 1: Comparing the Two Survey Methods Methods: Isolated all 6 minute recorded standard surveys (172 in total) Use “recognizers” to automatically detect and identify target species calls on recordings NO!! Ran into problems: missed detections and too many false positives

2 Manual Scan Method Resorted to the “Manual Scan” Method Quickly visually and aurally scan through recording to detect target species Robust design occupancy model in Program MARK

3 Probability of Detection -Each species -Each survey repetition -Each survey method

4 Why? Most calls not detected on ARU recording, but that were detected during Standard Survey, were too faint or not “strong” enough to be recorded by ARU – Reduced detection by ARUs was likely due to human observers being able to detect birds at greater distances

5 However Because ARUs are in the field for longer periods than human observers, there are more cumulative opportunities for detection

6 Objective 2: Factors affecting detection Looking at temporal and environmental variables that may affect calling and/or detection of these species Generalized linear mixed models in R – Presence/absence from 3035 three minute recordings, from 43 ARU stations – Hourly weather data

7 Variables of Interest Random effect = Survey Site Fixed effects = – Year – Julian day – Precipitation (yes or no) – Temperature – Wind speed – Atmospheric pressure – Moonlight – Hours after sunset

8 Yellow Rail Precipitation No precip. = 0.63 (95%CI = 0.55 and 0.71) Precip. = 0.47 (95%CI = 0.36 and 0.59)

9 Le Conte’s Sparrow

10 Nelson’s Sparrow Precipitation No precip. = 0.22 (95%CI = 0.16 and 0.30) Precip. = 0.08 (95%CI = 0.03 and 0.16

11 Management Implications Incorporate these factors into existing survey protocols to improve survey efforts –Standard surveys –Use of ARUs Improvement of systematic surveys

12 Acknowledgements Funding:


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