How to count 70 000+ Honey Buzzards

Well, like shown in this video on a day we counted up to 9000 Honey Buzzards in 20 minutes. Crazy!

“An example of good coordination and teamwork at the counting station. At least a 100 km long stream of Honey Buzzards was passing on the other side of the camera. http://www.trektellen.nl/count/view/1047/20170902 " — Video by Triin Kaasiku