Dove delivers Letter (Bulgaria 1931)

Stamp Dove delivers Letter it reflects the thematic directions:

The homing pigeon, also called the mail pigeon or messenger pigeon, is a variety of domestic pigeons (Columba livia domestica) derived from the wild rock dove, selectively bred for its ability to find its way home over extremely long distances. The rock dove has an innate homing ability, meaning that it will generally return to its nest using magnetoreception. Flights as long as 1,800 km (1,100 miles) have been recorded by birds in competitive pigeon racing. Their average flying speed over moderate 965 km (600 miles) distances is around 97 km/h (60 miles per hour) and speeds of up to 160 km/h (100 miles per hour) have been observed in top racers for short[clarification needed] distances.