Heath Outdoors 2 piece purple martin gourds available in 6 pack #30006. Purple Martin Gourds - in the eastern portion of the country are totally dependent on man made housing. Originally, Native Americans discovered that, if they put up hollowed out gourds, martins would use them for nesting. How this was discovered nobody really knows for sure, but they soon noticed that these martins would drive away some pests and predators such as crows and hawks. they also discovered that the martins consumed large quantities of pesky flying insects thus; the more gourds they put up, the more martins came and the fewer insect were around. Before long the martins learned to move from the trees to the gourds and around humans.