Evaluation of methods to estimate nocturnal bird migration activity: A comparison of radar and nocturnal flight call monitoring in the American West

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 ac..., , , # 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 ...