DOI: 10.5061/dryad.8w9ghx3x3
title: Data from: Evaluation of methods to estimate nocturnal bird migration activity: A comparison of radar and nocturnal flight call monitoring in the American West

description: Bird migration involves the movements of billions of individuals but is
 difficult to study because it occurs primarily at night. We sought to
 improve understanding of the methods available to study migration,
 particularly in understudied regions of western North America. We
 evaluated two methods: weather radar and nocturnal flight call monitoring.
 We analyzed variability in estimates of migration activity from each
 method, how estimates relate, and identified factors associated with
 variation in this relationship. We collected radar and flight call data
 from southern New Mexico in western North America during fall migration of
 2021 and 2022. Similar studies have occurred in eastern North America, but
 it is unknown if regional variability alters the relationship between
 estimates from each method. We found that estimates were positively
 related across a season, but relationships were variable among nights.
 Also, we discovered that the strength of the association between methods
 varied across sites, indicating that local factors may influence acoustic
 sampling. We determined that variation in acoustic estimates of migration
 activity was associated with cloud cover, crosswind, date, migrant height,
 migrant speed, moon illumination, tailwind, and time of night. For radar,
 we found crosswind, date, migrant height, migrant speed, tailwind, and
 time of night to be associated with variation in estimates of migration
 activity. Overall, our findings support those of previous studies from
 eastern North America and demonstrate that, despite regional differences,
 estimates from each method are also correlated in western North America.
 Our findings provide new insight into factors associated with variation in
 estimates of migration activity from two widely used methods and an
 improved understanding of factors that impact migration behavior.
description: # Evaluation of methods to estimate nocturnal bird migration activity: A
 comparison of radar and nocturnal flight call monitoring in the American
 West
 [https://doi.org/10.5061/dryad.8w9ghx3x3](https://doi.org/10.5061/dryad.8w9ghx3x3) ## Description of the data and file structure Data and code associated with the manuscript "Evaluation of methods to estimate nocturnal bird migration activity: A comparison of radar and nocturnal flight call monitoring in the American West" to be published in *Ornithological Applications*, February 2025. ### Files and variables #### File: RadarvsAcoustic\_Final.zip **Description:** Four items are included within this .zip folder. Two folders (Generated Data and Nighthawk Testing) include the data tables needed to run the two code files (Run First_Radar versus Acoustics_Bayesian Analysis and Run Second_Radar versus Acoustics_Models and Summary Statistics_Final). The two code files include all analysis that are presented within the manuscript and must be run in the order specified. Details pertaining to the data and code files are below- #### Generated Data Folder **ByDecile.csv:**  This file includes data for each site, for each night, for each decile of data collection. Exact specifications and descriptions of each variable and their calculation is included within the main text of the open access manuscript associated with this data. Column titles and description of data is below- SiteNightDecile- This column identifies the site (and year), night (corresponds to the ordinal date at sunset on the night data were collected), and decile (1-10, corresponding to the 1/10th of the night the data were collected) the data were collected. For instance, the first value is "WS2021_01_244_07" which corresponds to data collected at site 01 in 2021 on night 244 in decile 07.  CPH- The number of nocturnal flight calls detected by Nighthawk for the specific site, night, decile divided by the duration of that decile DecileDuration- The timespan of the specific decile in hours CallCount- the number of calls detected by Nighthawk for the specific site, night, decile NightDecile- the night and decile in which the data were collected DecileStart- The start date and time of that specific decile DecileEnd- The end date and time of that specific decile AveragevirKHDX- Averaged vertically integrated reflectivity as sensed by the KHDX weather radar during that night and decile, one value shared for all sites for each specific night decile combination as radar data was collected from a single radar AverageSpeedKHDX- Averaged speed of migrants (in m/s) as sensed by the KHDX weather radar during that night and decile, one value shared for all sites for each specific night decile combination as radar data was collected from a single radar AverageHeightKHDX- Average height of migrants (in m) as sensed by the KHDX weather radar during that night and decile, one value shared for all sites for each specific night decile combination as radar data was collected from a single radar AverageDirectionKHDX- Average flight direction of migrants (in degrees) as sensed by the KHDX weather radar during that night and decile, one value shared for all sites for each specific night decile combination as radar data was collected from a single radar Night- the night in which the data were collected, corresponds to the ordinal date at sunset on the night data were collected CloudCover- Average cloud cover within the decile of data collection as sensed by the Holloman AFB weather station and accessed from the Iowa State University environmental mesonet. Cloud cover is measured on a scale of 1-5 with 1 being no cloud cover and 5 being complete cloud cover, one value for all sites for that night as weather data was collected from one location near our recording sites Wind_direction- Average wind direction in degrees within the decile of data collection, provided by White Sands Missile Range meteorology branch, one value for all sites for that night as weather data was collected from one location near our recording sites Wind_speed- Average wind speed in m/s within the decile of data collection, provided by White Sands Missile Range meteorology branch, one value for all sites for that night as weather data was collected from one location near our recording sites Moon- Corresponds to the proportion of the moon that is illuminated above the horizon during that decile of data collection. Collected using getmoontimes and getmoonillumination function in r, one value for all sites for that night as weather data was collected from one location near our recording sites Crosswind- Average crosswind speed (exact calculation and formula provided in manuscript) in m/s for the decile of data collection, one value for all sites for that night as weather data was collected from one location near our recording sites Tailwind- Average tailwind speed (exact calculation and formula provided in manuscript) in m/s for the decile of data collection, one value for all sites for that night as weather data was collected from one location near our recording sites Year- Year in which the data were collected #### **ByNight.csv:**  This file includes data for each site, for each night of data collection. Exact specifications and descriptions of each variable and their calculation is included within the main text of the open access manuscript associated with this data. Column titles and description of data is below- SiteNight- This column identifies the site (and year), night (corresponds to the ordinal date at sunset on the night data were collected) the data were collected. For instance, the first value is "WS2021_01_244" corresponds to data collected at site 01 in 2021 on night 244.  Night- the night in which the data were collected, corresponds to the ordinal date at sunset on the night data were collected CPH- The number of nocturnal flight calls detected by Nighthawk for the specific site, on a specific night divided by the duration of that decile NightStart- The start date and time of that specific night NightEnd- The end date and time of that specific night Moon- Corresponds to the average proportion of the moon that is illuminated above the horizon during that night of data collection. Collected using getmoontimes and getmoonillumination function in r, one value for all sites for that night as weather data was collected from one location near our recording sites CloudCover- Average cloud cover within the night of data collection as sensed by the Holloman AFB weather station and accessed from the Iowa State University environmental mesonet. Cloud cover is measured on a scale of 1-5 with 1 being no cloud cover and 5 being complete cloud cover, one value for all sites for that night as weather data was collected from one location near our recording sites Wind_direction- Average wind direction in degrees within the night of data collection, provided by White Sands Missile Range meteorology branch, one value for all sites for that night as weather data was collected from one location near our recording sites Wind_speed- Average wind speed in m/s within the night of data collection, provided by White Sands Missile Range meteorology branch, one value for all sites for that night as weather data was collected from one location near our recording sites KHDXvir- Averaged vertically integrated reflectivity as sensed by the KHDX weather radar during that night, one value shared for all sites for each specific night decile combination as radar data was collected from a single radar KHDXSpeed- Averaged speed of migrants (in m/s) as sensed by the KHDX weather radar during that night, one value shared for all sites for each specific night decile combination as radar data was collected from a single radar KHDXHeight- Average height of migrants (in m) as sensed by the KHDX weather radar during that night, one value shared for all sites for each specific night decile combination as radar data was collected from a single radar KHDXDirection- Average flight direction of migrants (in degrees) as sensed by the KHDX weather radar during that night, one value shared for all sites for each specific night decile combination as radar data was collected from a single radar Crosswind- Average crosswind speed (exact calculation and formula provided in manuscript) in m/s for the night of data collection, one value for all sites for that night as weather data was collected from one location near our recording sites Tailwind- Average tailwind speed (exact calculation and formula provided in manuscript) in m/s for the night of data collection, one value for all sites for that night as weather data was collected from one location near our recording sites #### Nighthawk Testing Folder **NighthawkTest_RandomFiles2021.csv and NighthawkTest_RandomFiles2022.csv:** These two files include the randomly selected acoustic recording files that were then manually screened as a way to validate the performance of the Nighthawk model on our data. Column names are shared between the two files and detailed here- filename- The unique filename associated with the randomly selected audio file that was manually screened for nocturnal flight calls. The filename was included within this dataframe as it allows for identification of the site from which the recording originated and provided a way to identify where each call count came from. Duration- The duration of the recording associated with the file identified by filename StartTime- The data and time at which the recording associated with the file began Quarter- as all files were 1 hour in length, and we selected 15 minute segments for manual screening, this number corresponds to which 15 minute segment within the hour long file was screened NighthawkCalls- The number of nocturnal flight calls detected by Nighthawk within the randomly selected 15 minute segment ManualCalls- The number of nocturnal flight calls detected by manual screening within the randomly selected 15 minute segment ### Key Information Sources All weather data were provided by the Iowa State University Environmental Mesonet and accessed for the Holloman AFB weather monitoring station. All weather radar data were accessed and processed for the KHDX weather radar location using the BioRad package in r All nocturnal flight call recordings were collected using Wildlife Acoustics Song Meter Micro recorders on White Sands Missile Range. All recordings were processed using Nighthawk.  Further detail of these key information sources can be found within the open access manuscript associated with this dataset. ## Code/software Two R Markdown files are associated with this dataset and are needed to recreate analyses and figures associated with our manuscript. Run First_Radar versus Acoustics_Bayesian Analysis must be run first, and Run Second_Radar versus Acoustics_Models and Summary Statistics_Final must be run second. If you are wanting to run these files, you will need to set the appropriate working direction using the #Set working directory section at the beginning of each code file. R is required to run the two code files associated with this dataset; the two scripts were created and run using version 4.4.1 Code files are written in R Markdown and necessary libraries are specified within each code file. Annotations are provided within each of the two script files describing file setup, library and data loading, data processing, analyses, and figure creation