Pigeons are deeply respected creatures in Islam, symbolising peace and devotion to family, therefore the Iranians did not eat their meat and only kept them for their droppings. The birds were not forcefully captured but were instinctively attracted to the buildings due to the rock-like ledges and crevices resembling those in their natural environment. The birds were not kept domestically in the traditional sense, in that the tower owners did not provide them with food. They foraged during the day and returned to the towers in the evening. Isfahan was the area most heavily populated with pigeon towers, having around 3000 at its peak in the 17th century. Only around 300 remain standing in Isfahan, and due to recent advances in fertilisers, most are unused and rotting. However, 65 are protected under the country's National Heritage List.
Ghada Abdel Monem el Gemaiey of Cairo University in Egypt observed Iranian pigeon towers and concluded that they consist of three types:
| Cylindrical |
with a height of 11-16m and a diameter of 8-15m (found in Isfahan, Gourt, Shahr Reza, Najaf Abad, Qahderijan and Khaminey Shahr)
| Cubic |
with a height of 12-17m and a width of 4-8m (found in Khunsar, Gulpayagan and Khamyen).
| Polygonal |
with up to 12 sides, a height of about 10m and around a 21/2m diameter. These are more elaborate, requiring more skill to make than the other types, and are far less common - I could not even find a picture.