The dataset provided by Holling(1922) includes species and body masses of boreal forest birds. It is a commonly used dataset for discontinuity analysis. This dataset is not publicly accessible because: It is secondary data accessible online. It can be accessed through the following means: All data used are freely available and located in the appendix of Holling (1992):https://esajournals.onlinelibrary.wiley.com/doi/abs/10.2307/2937313. Format: Electronic text files. This dataset is associated with the following publication: Barichievy, C., D. Angeler, T. Eason, A. Garmestani, K. Nash, C. Stow, S. Sundstrom, and C. Allen. A method to detect discontinuities in census data. Ecology and Evolution. Wiley-Blackwell Publishing, Hoboken, NJ, USA, 8(19): 9614-9623, (2018).