Amazing! These migration patterns must be compiled from all of the observations that their app is used to identify; these kinds of crowd-sourced data products have the potential to change the way migration patterns are studied. I hope they are accounting for sampling bases, and cross checking with observation stations.

I help Copper Country Audubon [1] take data for similar studies at a much smaller scale in the Lake Superior region.

[1]: https://www.coppercountryaudubon.org/

Press play. Seek out other known birds or use the Cornell Merlin ID app to find more around you in North America

So many kinds of warblers.