Si wrote:was then eaten by a pigeon with apparently no heat discomfort whatsoever
birds don't have heat /pain receptors in their mouths. so, the hotter the chilli, the less likely it was to be eaten by mammals. so they were left for the birds. so the seeds travelled further, the hotter the plant. and thus is the beauty of evolution. and those seeds that grew better in bird droppings, did better. if you try to grow some again, ask a friend with a parrot for the muck from the bottom of the cage.
in parts of southern africa, crops are surrounded by a hedge of chillies. it keeps the elphants off the food crop.