SOLVED. Adult fiction. Competitive bird watcher whose competitor dies.

[Sara]

I believe this book was published during or before 2018.

The main character is a competitive bird watcher who is one of the top watchers in the world (or maybe the united states?). I believe one of his main competitors dies and he receives a tip for a rare bird that was maybe spotted in a remote area. There's definitely more intrigue but I can't remember any other plot points. Thank you in advance for any help you can give!

*edit* It's not the big year

[Sara]

I figured it out! It is the Life List of Adrian Mandrick

[Bargle]

Link The Life List of Adrian Mandrick by Chris White.