Ticks spread a number of diseases, plus they are disgusting and annoying. But which areas have the most? Where do hikers need to take precautions? Models have attempted to create "heat maps" showing when and where ticks are most abundant. Another approach uses citizen science data: where do people report seeing the most ticks?
I used iNaturalist data to compare relative abundance of ticks in several US states. iNaturalist users post photos of observations on the website, which can be easily queried in the Explore tab. However, some areas of the country have many more people using iNaturalist, so it is necessary to standardize the data by dividing by the total number of observations in each area. This creates a metric of the relative abundance of tick observations compared to total observations.
Another potential confounder is if some people specifically observe as many ticks as possible. This could skew the results if one state had someone obsessed with tick photography, and another state didn't. I corrected for this by subtracting observations from the #1 tick observer in each state. Only one state (CA) had this problem. This correction did not substantially change the results in CA, or any state.
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| Data compiled from iNaturalist.org |
The state/area with the most reports of ticks was California, but CA also had the greatest total number of observations of all life forms. When corrected for relative abundance, CA is near the middle of the distribution. Hartford, CT, famous for its tick abundance, topped the list. Arizona and Washington had the lowest relative abundance. Other top areas included MA, CT, ME, PA, and NY.
