BTO Ringers InfoBritish Trust for Ornithology
1.17 Varies with device
BTO Ringers Info: an app to help bird ringers, nest recorders and scientists check the correct ring sizes/codes to use for each bird species ringed in the UK (for both adults and pulli). Also contains useful info on the types of rings themselves (sizes, metal type, scheme address) and bird weight and wing length, where BTO data allow. BTO Nest record data (where available) and helpful codes are now included.