Date: 9/5/26 4:33 am From: Nathan Tarr (via carolinabirds Mailing List) <carolinabirds...> Subject: County Maps
Harry, Regarding your question about generating county maps from eBird data, I also have some resources that could help. However, Ivara’s maps look great and I can’t be of much help in the short term. I spent the last 4-5 years of my time with the NC Coop Unit and USGS National Gap Analysis Program (GAP) developing a process for attributing species to polygons. We needed to attribute all U.S. birds, mammals, and herps to 12-digit HUCs by integrating expert opinion and observations with existing maps, hopefully capturing range shifts over time. We were working nationally, but I developed a process that could be adapted and applied to any boundary polygons (i.e., counties) and spatial extent. Details are in this preprint: https://www.biorxiv.org/content/10.1101/2025.05.14.653500v1 . The case study is for the Fisher, but I have generated maps of birds in the past as well. I was set to publish that paper in the Journal of Fisheries and Wildlife Management and then revise all the GAP range maps under our new framework, but then Trump was elected, the program fell apart, and the journal told me they were no longer allowed to publish anything (they were affiliated with the FWS). The framework depends on software (really just a repository of code) that I built for curating occurrence records from GBIF and eBird that was published by the USGS: https://biss.pensoft.net/article/93823/ . It probably needs to be updated at this point as no one has been maintaining it. Also, the size of the EBD had become a barrier to use nationally, even with eBird's auk package. We (GAP) encountered many issues over the years while trying to incorporate and integrate occurrence records, expert opinion, predictive models, and historical maps and the framework we were about to adopt provided a way to deal with them. I would be happy to talk more about this, answer questions etc. if you are interested. I have been slowly working on applying the process for some personal projects in my free time (I’m doing public health data management at UNC now), but I’d be interested in helping with the BNC and Biodiversity Atlas if you want. Thanks for all your amazing work on the BNC website and everything else you contribute to conservation in NC! Nathan M. Tarr https://nmtarr.wordpress.ncsu.edu/
