They will be let loose in Valencia, Spain, on Saturday and then the race will be on to see which make it home to Portugal first.
This second “long-distance” pigeon race is taking place under the banner of the Portuguese federation of “Columbofilia”, taken from the Latin for carrier pigeon: Columba livia.
The 70,000 birds are either on their way to Spain already, or will be within hours, in a fleet of 15 specially-equipped trucks.
As newspapers report, these birds can travel distances of between 500 and 800 kilometres, without taking so much as a wrong turn.
Their release on Saturday will be simultaneous – hence the idea that the sky will be suddenly invaded by a veritable flapping cloud.