Many enthusiasts and scientists are recording and identifying birds from nocturnal audio recordings. Some references: - https://www.facebook.com/groups/Noctur

Many enthusiasts and scientists are recording and identifying birds from nocturnal audio recordings. Some references: - https://www.facebook.com/groups/NocturnalFlightCalls https://www.facebook.com/groups/NocturnalFlightCalls - https://github.com/HaroldMills/Vesper https://github.com/HaroldMills/Vesper - http://oldbird.org/pubs/fcmb/start.htm http://oldbird.org/pubs/fcmb/start.htm - https://nightmigrants.com/main/page_home.html https://nightmigrants.com/main/page_home.html