 The town of Griggsville, Illinois, proclaims itself the Purple Martin capital of the world. Before we go further, perhaps we should mention that a Purple Martin is a bird, the largest of the swallow family. But as pioneers settled the country, Brian Fitzgerald says something began to happen to these birds. When we started settling this, we started cutting down all their trees because they are second cavity nesters. So as we cut down all the trees, we took away their housing.