Anomolous increase in diurnal temps in the US after flights were grounded for 3 days following the 9/11 attacks. (Link).
Also, I noticed that after a couple of days, the birds were (for lack of a better word) acting cocky. Obviously I had no way to measure this, but I’m wondering if they think that airliners are high-flying predators?
I think we are perceived as competitors more so than predators
I also noticed birds in my area acting unusually brazen. They seemed much more inclined to perform bizarre aerobatics and fly in unusual formations. And I swear I saw one performing midair summersaults. Maybe they thought we had given up on the whole idea.