Purple Martins (Progne subis) are the largest member of the swallow family in North America, known for their social nature and aerial grace. These migratory birds migrate thousands of miles, spending winters in South America and returning to North America each spring for the breeding season. For centuries, a unique relationship has existed between these birds and humans, making the provision of specialized housing a long-standing tradition across the eastern half of the continent.
The Unique Dependence on Human Housing
The entire eastern population of Purple Martins is almost completely reliant on human-provided structures for nesting. While these birds historically used natural tree cavities, an ecological shift has made man-made housing, such as multi-compartment houses and hollowed-out gourds, their primary nesting site. Without human landlords, the Purple Martin population east of the Rocky Mountains would be unlikely to thrive or even survive.
The tradition began centuries ago with Native American tribes, including the Choctaw and Chickasaw, who hung dried gourds to attract the birds. Early colonial settlers adopted this practice, leading to the current biological reality where the birds’ reproductive success is tied directly to human stewardship. Establishing a Purple Martin house is an active commitment to conservation, ensuring the continuation of this unique avian species.
Ecological Services and Natural Pest Control
A primary motivation for hosting a Purple Martin colony is the substantial ecological service they provide through natural insect control. These birds are aerial insectivores, capturing all of their food while flying and consuming a wide variety of airborne arthropods. Their diet includes numerous flying pests such as flies, midges, grasshoppers, wasps, and beetles.
Although often cited as a natural solution for mosquitoes, this is largely a misconception, as mosquitoes make up a small fraction of their diet. Martins primarily feed at higher altitudes during daylight hours, while mosquitoes are most active near the ground at dusk or night. However, the birds are highly effective at controlling larger insect pests, including agricultural pests like flying fire ant queens and Japanese beetles. Providing a home for martins offers a chemical-free method of managing the flying insect population around a property.
Beyond pest management, a significant benefit is the pleasure of observing the colony’s life cycle. The birds are highly social, communicating with a distinctive, gurgling song that fills the air with sound and activity. Watching their spectacular aerial acrobatics and complex social interactions provides an aesthetic benefit that many enthusiasts find rewarding. This enjoyment is often the strongest incentive for becoming a dedicated Purple Martin landlord.
Essential Site Selection Criteria
Success in attracting a Purple Martin colony depends heavily on selecting a location that meets their specific habitat requirements. The most important factor is open space, as the birds need clear, unobstructed flight paths to safely access their nests and forage. The housing structure should be placed in the most open area available, ideally with no tall trees within 40 to 60 feet.
The proper height of the structure is also important, with the favorable range being between 12 and 20 feet above the ground. This height helps deter ground predators and provides the martins with the necessary elevation for their characteristic diving approach. Purple Martins prefer to be near human activity, so placing the house within 30 to 100 feet of a dwelling can increase the chances of attracting a colony.
A final consideration is proximity to a water source, which is advantageous for attracting the birds. While they do not use bird baths, an open body of water like a pond, lake, or river within a mile or two provides them with drinking water and mud for nest building. Improper placement is the most common reason for failure in establishing a colony, so adhering to these precise criteria is crucial for a successful setup.