1. He has started carrying around a backpack. No matter where he is going.
  2. You notice he’s frequently typing away on his phone and when you ask who he’s so busy texting, he says he’s “making a list on eBird.”
  3. He’s often gone when you wake up and is out sometimes late at night. And returns groggy and disheveled.
  4. He’s been trying out different mating calls.
  5. You’ve caught him googling “Brown Booby,” “Great Tit,” and “Cock-of-the-Rock.”
  6. He often stares out your apartment window with binoculars.
  7. He’s never been very athletic but suddenly he is going on long walks and hikes.
  8. He has started hanging out with a group of older white men.
  9. He doesn’t believe in getting law enforcement involved in wooded Central Park-related incidents.

1, 2, 3, 4, 5, 7: Cheating on you
1, 3, 6, 7, 8, 9: Likely serial killer
1-9: Just an avid birder