North American bird declines are greatest where species are most abundant

Efforts to address declines of North American birds have been constrained by limited availability of fine-scale information about population change. Using participatory science data from eBird, we estimated continental population change and relative abundance at 27 km resolution for 495 bird species from 2007-2021. Results reveal high and previously undetected spatial heterogeneity in trends; although 75% of species were declining, 97% of species showed separate areas of significantly increasing and decreasing populations. Populations tended to decline most steeply in strongholds where species were most abundant, yet they fared better where species were least abundant. These high-resolution trends improve our ability to understand population dynamics, prioritize recovery efforts, and guide conservation at a time when action is urgently needed., The data files in this archive provide estimates of population change and relative abundance at 27 km resolution for 495 bird species from 2007-2021 using participatory science data from eBird. Additional data files are included in the archive that provide simulation-based model performance metrics. For further details, consult the associated paper North American bird declines are greatest where species are most abundant (Johnston et al. 2025)., , This archive contains data for *North American bird declines are greatest where species are most abundant* (Johnston et al. 2025).

## Abstract

Efforts to address declines of North American birds have been constrained by limited availability of fine-scale information about population change. This archive accompanies a paper that describes the use of data from the participatory science project eBird to estimate continental population change and relative abundance at 27 km resolution for 495 bird species from 2007-2021. The archived materials, divided across Dryad and Zenodo, are composed of all data and R code that are necessary to conduct the analyses and produce the figures from this paper. The README.md file for this archive, which is part of the Dryad component of the archive, describes each of data files contained within the archive.

## Content

The full archive is split between Dryad and Zenodo; the Zenodo components of the data cannot be archived in Dryad because they inherit op...,