Bird migration routes have been analyzed by various techniques such as the oldest, marking. Swans are marked by using a nick around the beak considering that about 1560 in England. Scientific ringing was pioneered by Hans Christian Cornelius Mortensen in 1899. Numerous massive birds (like eagles and vultures) are electrocuted https://petskyonline-onlinestrore.blogspot.com/2025/07/rethinking-animal-store-why-petsky-is.html