Birds of Europe Field Guide
Ecosystema
European Birds Songs & Calls
Bird Decoys: Songs and Calls
Picture Bird - 拍照識鳥
Next Vision Limited
Merlin 鳥種識別 by Cornell Lab
Cornell Lab of Ornithology
BirdNET
Stefan Kahl
Collins Bird Guide
NatureGuides Ltd
Birdie Memory
Merle Blanc
eBird by Cornell Lab
Bird Life -小鳥生活-
Cross Field Inc.