Long before people inhabited North America, Purple Martins nested in natural cavities – usually old woodpecker holes and in most of the western states, they still do. So how did the Martin population east of the Rocky Mountains become so dependent upon humans to provide the cavities in which they nest?
We can only speculate, but many people believe that Martins were inadvertently attracted to Native American Indian villages by flies, gnats and other insects that proliferate around food and animal waste. The Indians used dried, hollow gourds for many purposes and it’s not surprising that a Purple Martin in search of a nesting cavity would find that a broken gourd hanging on a tree branch in the vicinity of food supply would work just fine.
The Indians enjoyed Purple Martins for some of the same reasons that people enjoy them today – their beautiful acrobatic flight and their pleasing and cheerful song. They also observed that Martins nested in groups, captured many insects for themselves and their young, gave distinct warning calls when danger was present and readily chased away crows. Who wouldn’t want these beneficial birds nesting nearby?
Perhaps by accident, Indians discovered that Martins could be lured close to their villages by hanging large hollow gourds with holes cut out of their sides and thus began the relationship to benefit man and bird.
Early American settlers saw the benefits of having Purple Martins nesting nearby and adopted the custom of hanging gourds near their farms and inns. The settlers came from Europe where they didn’t have gourds, but they did build birdhouses, which is probably why they built Purple Martin houses.
It is thought that by nesting in gourds and houses near human habitation, Martins were less threatened by predators which were either hunted or chased away by humans. The larger cavities allowed them to raise more young and more Martins returned to nest in the same way. As the human population grew and spread, the Martins’ original habitat decreased and the number of Purple Martins still nesting in natural cavities declined. Today, because of this shift in behavioral tradition and the loss of natural nesting cavities, the continued survival of Purple Martins depends almost entirely upon housing provided by people.
The early Martin houses were usually made of wood and some were extremely ornate, serving as much a decorative purpose as functional. Modern technology has resulted in the development of aluminum houses which are lighter and more durable. Artificial gourds and even some houses are now produced using modern plastics.