Up Until the 1930's Penzance and the other villages in Mount's Bay were the scene of large May Day Celebrations centred around the blowing of large tin horns. The following text is from Robert Hunt's Popular Romances of the West of England

THE first of May is inaugurated with much uproar. As soon as the clock has told of midnight, a loud blast on tin trumpets proclaims the advent of May. This is long continued. At daybreak, with their "tintarrems," they proceed to the country, and strip the sycamore-trees (called May-trees) of all their young branches, to make whistles. With these shrill musical instruments they return home. Young men and women devote May-day to junketing and picnics.

It was a custom at Penzance, and probably at many other Cornish towns, when the author was a boy, for a number of young people to sit up until twelve o'clock, and then to march round the town with violins and fifes, and summon their friends to the Maying.

(A picture of an original pre-1930's May Horn)

When all were gathered, they went into the country, and were welcomed at the farmhouses at which they called, with some refreshment in the shape of rum and milk, junket, or something of that sort. They then gathered the "May," which included the young branches of any tree in blossom or fresh leaf. The branches of the sycamore were especially cut for the purpose of making the "May-music." This was done by cutting a circle through the bark to the wood a few inches from the end of the branch. The, bark was wetted and carefully beaten until it was loosened and could be slid off from the wood. The wood was cut angularly at the end, so as to form a mouth-piece, and a slit was made in both the bark and the wood, so that when the bark was replaced a whistle was formed. Prepared with a sufficient number of May whistles, all the party returned to the town, the band playing, whistles blowing, and the young people singing some.

Further Reeading on the Traditions of Mayday in Penzance etc Penzance May Day Google Book Search.

In 2008 Penzance revived the May horns custom, a picture of the event appears above. For information dates and times of the 2009 and future events please visit the May Horns official website http://www.penzancemayhorns.co.uk/.

St Ives has held its own May Day celebrations similar to the above since it was revived in 2001. Paul Village and Mousehole have continously retained many of the above customs.