About WhenToBird

WhenToBird answers one question: when and where will I see this bird?

eBird has the data and it is excellent, but getting a plain answer for your state, on your phone, takes several screens. Here every bird has a page per state with the arrival week, the peak, the departure and the counties and spots to try, built from the same checklists and shown with the sample size.

We try to be honest about what the numbers are. Frequency is a share of checklists, not a count of birds, and we say so on every page. Weeks with too little data are grey, not guessed. The method is on the methods page.

The site is free to read, with no ads. The app is how we pay for it. WhenToBird is independent of the Cornell Lab of Ornithology and eBird; their data, shared under CC BY 4.0 through GBIF, is what makes it possible.

Contact: hello@whentobird.com