This repository contains code and data for Callaghan et al. 2021. Global abundance estimates for 9,700 bird species. PNAS. (https://doi.org/10.1073/pnas.2023170118). This readme is intended to provide an overview of the data analysis. eBird data are free to download (https://ebird.org/data/download) and we used the eBird basic dataset (version ebd_relMay2019). The first thing to note is that the eBird dataset is a ‘live’ dataset whereby records from the past can be added or removed currently. This means that we could have used a record in our dataset that was present when we downloaded the data, but no longer present. This readme is set up to guide an interested user through the repository and only focuses on highlighting the main steps/workflow and does not highlight the function of every R script. It anticipates that a reader has read the Methods section of the paper in detail.