Attracting and Maintaining Purple Martins
By Mark A. Bailey
February 2001
Volume 1, Issue 2
Download PDF
Purple martins are fascinating birds. This largest of North America’s swallows originally nested in natural cavities such as woodpecker holes. The species has now become almost entirely dependent on multi-chambered “martin houses” put up on poles in yards and fields near human dwellings. Martin houses can be elaborate or simple. Indians were the first to entice martins to nest in gourds, and this practice still continues in the South.
Actually blue-black, purple martins appear black at a distance. The tail is moderately forked. The first martins arrive from South America to our Gulf Coast by early February, reaching Tennessee by mid-March. These early birds are often called “scouts,” but are really older martins who know where to find last yearᰱs nest site.
Adults have a strong fidelity to sites at which they previously nested. Males generally arrive at nest sites before females.
Yearling birds begin arriving 4 to 6 weeks after the adults, and these are the birds most likely to be “on the market” for new and unoccupied martin houses.
Flying insects are the chief food of purple martins, and although they do catch some mosquitoes, they are not the “skeeter eaters” that some martin house vendors would have you believe. Favorite prey items include wasps, beetles, grasshoppers, dragonflies, horseflies, and moths. Ants and spiders are occasionally caught while walking on the ground. For needed calcium, purple martins are very fond of bits of eggshell (hen’s eggs) scattered on the ground near their nests.
The landlord of a colony of purple martins is richly rewarded. These handsome birds not only help control insects, but they are fun to watch. They chirp loudly, darting about, then soaring, often even flying and calling at night. Also, they are just finicky enough about where they’ll live that successfully attracting and establishing a breeding group at your property is something to be proud of.
If you have the know-how and some open space, you can have martins. Too many people make the mistake of buying or building a martin house before thoroughly researching the subject. Only after investing money, time, and hard work, they discover that their yard is too tree-enclosed for martins, or their martin house is poorly designed and/or difficult to maintain. The advice given here is a starting point to increase your chances of attracting martins. Once martins nest at your location, they will come back every year if you manage the site properly.
Location is Everything
Martins have very specific space requirements. The main reason people fail to attract martins is that they place their housing in the wrong part of their yards, or their yards are inappropriate martin habitat to begin with.
Martin housing should be in the center of an open area, at least 30 feet from human housing. Place the housing where you can enjoy watching and hearing the birds. There should be no trees within at least 30 feet, and the farther from trees, the better. The air space immediately around the housing, at the height of the housing, should be free of trees in at least two directions, so that the martins can fly to and from the housing in nearly level flight. Housing height should be about 10-15 feet.
Don’t Open Martin Housing Too Early
Adult martins return to the sites where they bred previously. As stated earlier martin yearlings (last year’s young) are the ones that colonize new sites, and they begin arriving about 4 weeks after the first adults. At new sites, opening housing when the adults are due to arrive decreases chances of attracting martins by giving house sparrows and starlings a month to claim the site before the yearlings arrive.
To improve your chances, keep housing closed until it’s time for yearlings to arrive. The lines on the map show average arrival dates of older martins returning to established colony sites. Remember, the yearlings appear 4-6 weeks after these dates, and continue arriving for an additional 10 weeks or so. This means martins can be attracted to new housing through June.
At established (previously used) sites, the first martins usually show up within a week or two of previous years’ arrival dates, so keep notes. Have your housing ready, but keep it closed until some martins return and show interest in the housing. They’ll wait a few days for you.
Martin migration is much more drawn out than once was thought, with birds arriving over a span of 16-20 weeks. Martins can arrive and begin nesting as late as June, so keep your housing ready; don’t close it up, or let other birds use it.
Use Proper Housing
You must tend the housing each year, so choose a pole that telescopes or is equipped with a winch. Housing should have easily accessible compartments. Paint houses and gourds white to reflect sunlight and keep nestlings cooler. White housing also seems to attract martins best. Martins prefer larger compartment floor dimensions (7'' x 12''), and dimensions should be at least 6'' x 6.'' Compartment heights can be 6'' or 7.'' Place entrance holes 1'' above the floor. An entrance hole of 2'' (plus or minus a quarter inch) is adequate. Make sure each compartment is adequately ventilated and has drainage.
Guard against Predators and Nest Site Competitors
Raccoons, rat snakes, crows, and owls are all potential predators. Don’t lose all your martins because you didn’t protect against predation. External guards are available that protect against owls, hawks, and crows. All martin poles, whether wood or metal, must have climbing animal barriers. You can install guards before or after your martins have arrived.
Starlings and house sparrows will take over and prevent martins from nesting at new sites. Successful martin landlords do not tolerate these non-native competitors.
Keep Housing in Good Repair
After your martins have left in the fall, remove nests and scrub the housing with a 10% bleach solution (1 part household bleach to 9 parts water). Rinse and air dry before storing for the winter. Wooden houses and natural gourds need to be sanded and repainted periodically. Martin housing will last longer if stored indoors over the winter. If you leave housing outside, plug the holes, or else house sparrows and starlings will claim it in late winter.
Educate Yourself and Enlighten Others
Visit www.purplemartin.org, the Purple Martin Conservation Association’s (PMCA) web site, talk with other landlords, and read PMCA’s “Enjoying Purple Martins More” and/or “Stokes’ Purple Martin Book.” PMCA members benefit from current information published in Purple Martin Updatemagazine.
Martin landlords love to talk about their birds. Stop and introduce yourself to other landlords, and make some new friends. Ask your local newspaper to do a story on martins, and have meetings to share information. By promoting good management, you can help increase martin numbers locally. And, if you can help area landlords become better educated and more involved in management, you’ll assure a better supply of fledglings each season to help martin populations thrive.
If you enjoyed this article, and would like additional information about becoming a subscriber, Click Here.
 Back to Top
|
