This project contains CT scan data for 19 bird specimens sampled in [Legendre et al. (2024, *Zoological Journal of the Linnean Society*)][1]. The data is hosted on Box as .zip files (one for each specimen). Due to file size constraints, data for specimen FMNH 320844 (*Phlogophilus harterti*) is in two separate .zip files. Scans for two specimens of *Oreotrochilus chimborazo* sampled in Legendre et al. (2024) are not included here due to them being part of the supplementary material of a forthcoming study. Each file has the title format: "Genus_species_specimennumber" and contains: - A folder with 16-bit images of the scan, in TIFF format (high resolution) - A folder with 8-bit images, in JPG format (low resolution) - A 'contents.docx' file that summarizes information about each specimen, including scanning parameters The dataset, tree, and code used in this study, all uploaded on GitHub, are also linked in this repository to ensure full replication. Additional data are available as Supplementary Information of the paper ([Tables S1, S2, and S3][2]). [1]: https://doi.org/10.1093/zoolinnean/zlae001 [2]: https://academic.oup.com/zoolinnean/advance-article/doi/10.1093/zoolinnean/zlae001/7609951#supplementary-data