Some church steeples are topped with a rooster, instead of a cross. Why is this?

The most common reason seems to be:

"The rooster is a symbol for the Apostle Peter, the first Pope. The symbol refers to the cock (rooster) crowing during the Passion narrative, the incident that causes Peter to realise his betrayal of Christ. Christ told Peter during the Last Supper that He would be denied three times before 'the cock crows', Peter denied that he would ever [forsake] His Lord, yet out of fear, he did."
http://www.domestic-church.com/CONTENT.DCC/19990901/EDITORIAL/misc_questions.htm

From my window in Normandy I can see our local Catholic church with a rooster on the steeple. Also we are about half an hour from the sea. This disproves two of the above answers.

Finally found a site that lists some sources - Wikipedia. :-|

"In the sixth century, it is reputed that Pope Gregory I declared the cock the emblem of Christianity saying the rooster was "the most suitable emblem of Christianity",[73] being "the emblem of St Peter".[74][75] Some say that it was as a result of this that the cock began to be used as a weather vane on church steeples, and some a Papal enactment of the ninth century ordered the figure of the cock to be placed on every church steeple.[76] It is known that Pope Leo IV had the figure of the cock placed on the Old St. Peter's Basilica."

https://en.wikipedia.org/wiki/Rooster#Christianity