Late summer in Puerto Rico is when you start to see these fruit like gourds growing in abundance on trees along side many a road ways, or cow pasture, or abandoned lot.
When the have reached maturity they fall to the ground most often than not in tact. Where they stay until, rotted or someone harvests them. The best time to collect these however is before they become dry and still have their glossy green skin.
They are much easier to open and clean and sculpt or carve. Plus they tend to smell when they are dry rotted on the ground. The pulp turns black, sometimes mold grows, and insects inhabit the gourds.