Why are weather vanes traditionally depicted with a cockerel on top?
ADevices to indicate the
direction of the wind are quite ancient, emerging independently in places as far apart as Sumer (modern-day southern Iraq) and China.
The first one that we know a lot about was the Tower of the Winds in Athens, in the first century BC. The octagonal marble tower had a bronze figure of Triton pointing a rod at whichever of the eight Greek wind gods was prevailing.
By around the third century AD (and probably sooner) the Chinese had weather vanes in the shape of birds. Perhaps it was because some birds take off into the wind (and others ‘ hover’ by flying into a headwind). Maybe it was just because an ornamental bird seemed an obvious thing to have up in the air on the unobstructed high point needed for accuracy.
In the Mediterranean, there is mention of cockerels on weather vanes as early as AD 200, while the oldest in Italy dates from the early 800s. Various popes are supposed to have decreed that weather vanes on churches should take cockerel form, and they were common by the early Middle Ages. The 11th-century Bayeux Tapestry even shows a man climbing onto the roof of Westminster Abbey in order to plant a weathercock.
The religious meaning is usually put down to Christ’s prediction at the Last Supper that Peter would disown him three times before the cock crowed next morning. It is thus a symbol of God’s mercy in that Peter was forgiven after repenting his seemingly unforgiveable betrayal.
Alternatively (or also), the cockerel was a pagan motif, usually of the rising sun or daybreak, which was adopted by Christianity to symbolise the light of the new day and new beginnings.
In purely practical terms, a flat ornamental rooster is a good choice because its big tail easily catches the breeze.