DOI: 10.5061/dryad.g79cnp617
title: Data from: A call in the dark: Nocturnal flight calls and their potential to advance the study of avian migration

description: Migratory birds have experienced widespread declines in abundance and face
 numerous threats. The conservation of migratory species relies in part on
 an improved knowledge of active migration behavior, but this behavior is
 difficult to study as most birds migrate at night. Flight calls, which are
 species-specific calls produced by many nocturnal migrants during flight,
 offer an opportunity to improve our understanding of migration behavior
 and serve as a tool to monitor populations. Although nocturnal flight call
 monitoring has been historically limited to small spatial and temporal
 scales, recent technological advancements have allowed researchers to
 largely shed these constraints. Despite this expansion, there are many
 unanswered questions regarding the function of flight calls and the
 proximate drivers of calling behavior. There are also unaddressed concerns
 that the methods used to record nocturnal flight calls, as well as other
 organismal, environmental, and social factors, may bias data in ways that
 impede (or prohibit) comparisons across time and space. Research that
 addresses these limitations and potential sources of bias will advance the
 use of nocturnal flight call monitoring for migratory bird
 research.  
description: Data for Figure 1 (The number of peer-reviewed publications using
 nocturnal flight call monitoring to address ecological, behavioral, or
 methodological questions by year from (a) 1899 to 2024 and, (b) 1999 to
 2024), were generated using the Web of Science online database with the
 search term “nocturnal flight call AND bird”. The search was conducted on
 June 25th, 2024. All titles and abstracts were screened to ensure the
 relevance of included articles. Articles cited within relevant articles
 produced by the search were screened for inclusion as well. All articles
 can be found in the table
 "Screened_WebofScienceSearch_6.24.24.xls" associated with this
 dataset. Code to generate Figure 1 can be found int he
 "Figures1and3.RMD" document associated with this
 manuscript. Data for Figure 3 (An example of how
 weather conditions (in this case, strong headwinds aloft) may lower the
 flight height of migrants, causing an increase in call rates (nocturnal
 flight call per hour, NFC/hr) detected at ground-based autonomous
 recording units that is not attributable to changes in the density of
 birds aloft (as measured by radar). Panel (a) depicts avian migrant
 density at various heights above ground level (agl) as measured by the
 KHDX Next Generation Weather Radar in southern New Mexico on the night of
 September 30th, 2022, showing migrants clustering at low flight heights,
 most of which are below the horizontal dotted line representing the
 maximum sampling height of ground-based autonomous recording units
 (although this height has not been well defined). Panel (b) depicts
 headwinds aloft (assuming southbound migration) within the area sampled by
 the KHDX radar on the same night, indicating strong headwinds aloft and
 weaker headwinds at ground level. Panels (c) and (d) depict the same data
 as (a) and (b) but for a night (September 8th, 2022) in which headwinds
 were more evenly distributed, resulting in more migrants flying above
 recorder sampling range), were generated using the bioRad package in r
 (Dokter et al. 2019), wind data were accessed from the North American
 Regional Reanalysis dataset (Mesinger et al. 2006). Nocturnal flight call
 data were extracted from the dataset- https://doi.org/10.5061/dryad.8w9ghx3x3. Code to create figure 3 can be found in the "Figures1and3.RMD" document associated with this dataset. This code file also includes all necessary information for processing radar and wind data.
description: # Data from: A call in the dark: Nocturnal flight calls and their
 potential to advance the study of avian migration
 [https://doi.org/10.5061/dryad.g79cnp617](https://doi.org/10.5061/dryad.g79cnp617) ## Description of the data and file structure Data were pulled from multiple sources to generate the figures associated with this manuscript- For figure 1, data were generated using the Web of Science online database with the search term “nocturnal flight call AND bird”. The search was conducted on June 25th, 2024. All titles and abstracts were screened to ensure the relevance of included articles. Articles cited within relevant articles produced by the search were screened for inclusion as well.  For figure 3, the bioRad package in R was used to obtain weather radar data for the KHDX radar site for the time period of interest. Wind data were accessed from the North American Regional Reanalysis dataset. Nocturnal flight call data were obtained from the dataset here-[https://doi.org/10.5061/dryad.8w9ghx3x3](https://doi.org/10.5061/dryad.8w9ghx3x3) ### Files and variables #### File: Screened\_WebofScienceSearch\_6.24.24.xls **Description:** Data were generated using the Web of Science online database with the search term “nocturnal flight call AND bird”. The search was conducted on June 25th, 2024. All titles and abstracts were screened to ensure the relevance of included articles. Articles cited within relevant articles produced by the search were screened for inclusion as well. The variables described below are only those that are relevant to the manuscript associated with the dataset, and do not reflect all variables generated by the original Web of Science search. Due to the nature of the Web of Science search, some cells contained no value and these cells were filled with "null". ##### Variables * Publication Type: Created from Web of Science, corresponds to the type of publication * Found in Initial Search?: Y (yes) or N (no), depending on whether the article was found in the initial Web of Science search (Y), or if it was added following screening of articles from the search (N). * Found in Literature Screening?: Y (yes) or N (no), depending on whether the article was found in the initial Web of Science search (N), or if it was added following screening of articles from the search (Y). * Authors: the authors of the article * Article Title: Title of the article * Source Title: Journal Title * Publication Year: year the article was published #### File: NARRWindDataSep30Oct01.csv **Description:** Wind data accessed from the North American Regional Reanalysis dataset for the first time period of focus for inclusion with Figure 3 in the associated manuscript. ##### Variables * latitude: Latitude in decimal degrees * longitude: Longitude in decimal degrees * SurfaceHgt: Height of measurement in m above sea level * uwind: U wind component in m/s * vwind: V wind component in m/s * hgt: Height of measurement in m above ground level * pressures: Pressure level zone associated with the height of the measurement * date: Date of the measurement * utc: Time (in utc) of the measurement * windDir: Direction of the wind in degrees * windSpeed: Speed of the wind in m/s * pressureslevel: Pressure level zone associated with the height of the measurement #### File: NARRWindDataSep0809.csv **Description:** Wind data accessed from the North American Regional Reanalysis dataset for the first time period of focus for inclusion with Figure 3 in the associated manuscript. ##### Variables * latitude: Latitude in decimal degrees * longitude: Longitude in decimal degrees * SurfaceHgt: Height of measurement in m above sea level * uwind: U wind component in m/s * vwind: V wind component in m/s * hgt: Height of measurement in m above ground level * pressures: Pressure level zone associated with the height of the measurement * date: Date of the measurement * utc: Time (in utc) of the measurement * windDir: Direction of the wind in degrees * windSpeed: Speed of the wind in m/s * pressureslevel: Pressure level zone associated with the height of the measurement ## Code/software The "Figures1and3.RMD" document here is used to create figures 1 and 3 within the manuscript associated with this dataset. All necessary packages are stipulated within the document and the code is annotated to describe workflow. All data not generated within the code file are included within the files associated with the dataset here.  ## Access information Other publicly accessible locations of the data: * NA Data was derived from the following sources: * NA