What Bird Is That Forum

Hi folks. I wanted to make a map of the most-commonly sighted birds across the U.S. Check it out! Does it seem reasonable? Do you agree with your state?

Method: I downloaded eBird data for each state over the 10-year period from 2016-2025 (example for NC: https://ebird.org/barchart?byr=2016&eyr ... 12&r=US-NC). This data gives a "frequency" metric, which is calculated as the fraction of birder checklists that include a specific bird (regardless of if the birder saw 1 or 100 of those birds). The data is approximately weekly, so I computed annual-means weighted by the number of days in each "week." (It seems like the first three weeks of each month are 7 days each, and the final week has the remainder).

As SirVive pointed out, this data will be weighted toward more charismatic, easier to recognize birds (sorry sparrows!). If you'd like to know the top 10 for a given state, let me know. Also, let me know if you have suggestions to improve the map. A note: If I calculate means weighted by number of observations instead of time, some states change. Would that be a better metrics? It would weight the results toward the times of year that birders bird, but that's probably when the most bird are around.

Interesting map. I'm kinda surprised that the top isn't also AMRO in WA but crows are certainly common. And that outlier SOSP I wonder if there's a way to show the %, as in 'likelihood' if you go out birding that you'll see X without making it too cluttered? Is it 20 or 80% of checklists that have an X sighting?

Thanks. I agree that it's a little surprising, and probably biased in a variety of ways. For Washington, the top three birds (American Crow, Song Sparrow, and American Robin) are all very close, appearing on around 46% of lists. The number four bird (Dark-eyed Junco) appears on about 40% of lists. If I weight the annual mean by number of lists instead of doing a time-average, American Robin becomes #1 just barely.

Showing percentages might be interesting, but would probably produce too much clutter. Plus, I think it's a little deceptive to show those percentages, since the data is compiled by people actively looking for birds, instead of normal people going about their day. For example, in NC, the Northern Cardinal shows up on 63% of lists, which sounds pretty high. (And frankly, in my region, I'd say the Song Sparrow is much more common).

Cardinals are definitely the most common bird here in Texas.