- Swallows, Martins
Purple Martins, large swallows that nest together in colonies, are completely dependent on nest boxes for nesting sites in the eastern United States, though not in the west. Martins need specially designed martin houses, as well as adequate open space where they can hunt for dragonflies and other flying insects. Purple Martin "landlords" can help these birds with appropriate martin housing, and by protecting birds and their housing from aggressive European Starlings and House Sparrows.
What Purple Martins Need
Food: Purple Martins eat a wide range of flying insects that they hunt and capture in flight, often over 150 feet above woodlands, open areas, and waterways. During prolonged cold and or wet weather when insects aren't flying, martins may perish from starvation. During egg-laying, female martins may eat eggshells or other sources of calcium needed for egg laying. Martins regularly swallow small amounts of sand or gravel as grit to help digest their insect prey.
Nesting: Martins prefer housing mounted on a pole 10 to 17 feet high and placed 30 to 120 feet from human housing. It should also be at least 40 to 60 feet away from nearby trees in order to provide a clear glide path for approaching martins. Nest compartments that are 12 inches deep and 6 inches wide provide additional safety from predators. Martins prefer to nest in colonies, and in some areas may not colonize new sites without decoys or audio recordings of calls to attract them.
Shelter: During the breeding season, martins sleep in their nest compartments. During late summer and during migration, birds congregate in large migratory roosts that may number hundreds of thousands of birds--often on islands in rivers, bridges, or on commercial buildings where they may seek protection from disturbances, weather, owls, and other predators.
How You Can Help
* Consider creating a dragonfly pond to attract and breed these insects preferred by martins.
* Avoid applying pesticides that kill or poison flying insects that martins eat.
* In cold weather, provide mealworms or crickets as a supplemental food source.
* Offer chicken eggshells on a platform feeder for egg-laying females.
* Maintain a pile of small gravel or sand in an open area for grit.
* Purchase or construct and install appropriate martin housing.
* Protect houses from predators by installing appropriate predator guards on housing poles and owl guards on front of housing.
* Protect martin colonies from European Starlings or House Sparrows by trapping or otherwise removing these non-native nest site competitors.
* More martin information available online at www.purplemartin.org.
* If you own or manage a commercial building that has attracted a migratory roost site, protect the birds and publicize their arrival as a way to generate publicity for your property.
* Keep martin houses open even after local birds have finished nesting. to provide roosting sites for wandering young birds.