For centuries Iran relied on pigeons to supply guano as fertilizer for the fields. The guano was collected in almost 3000 squat, circular pigeon towers (dovecotes), each able to house about 14,000 birds. (read about it here >>>)

Pigeon flying has been a popular sport in Iran for many centuries and is practiced throughout the country. The whistling of the pigeon trainers is heard often over the rooftops of the town of Tehran…

read about the interesting history of Pingeon Flying:
The Practice of Pigeon Flying in Southern Tehran and its Image in Iranian Society
Alexander Reddaway (2007)