Oddly enough, the purple martin isn’t purple, but a shiny blue so dark one might mistake it for black.
Few birds have as fascinating a history as the purple martin, the largest North American swallow. It’s believed by ornithologists that centuries ago, when the martin was nesting in hollow trees, a Native American hung a hollow gourd at the top of a pole and a pair of purple martins raised a family in it. It is this legend that is said to have begun the long friendship between the purple martin and humans.
Purple Martins Love People
Unlike many species of birds who remain skittish around people, purple martins love us. Over time, ornithologists have come to believe that without the help of people, the purple martin would not be able to nest and raise its young. This is due to the rise in popularity of the very specific housing the purple martin requires, the purple martin house.
Purple martin houses are unlike any birdhouse you may have hung in your backyard. They’re easy to spot as they look like apartment houses for birds. Typically, the martin house has multiple levels, and as many as three or four. What makes them easy to spot is the fact that martin houses are not hung from trees but mounted on poles. Most martin houses are octagonal or rectangular in shape and have multiple circular openings to allow the martin to come and go.
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Birdwatchers in the eastern half of the United States have been enamored by the purple martin for hundreds of years. If you were to walk through several suburban neighborhoods there, you may be surprised at how many purple martin houses you would spot.
Attracting the Purple Martin
If you’re interested in attracting purple martins to your backyard, you will need to meet specific requirements in order to be a proper landlord of a purple martin house.
Unlike other bird species who build their own homes, the purple martin relies on people for appropriate housing. There are a multitude of purple martin houses to choose from through local garden supply stores or online through companies that specialize in bird feeders. When choosing a purple martin house, keep in mind the entrance (many offer starling resistant entrances) and the number of compartments.
Purple martins are colonial nesters. Bird species that are colonial nesters breed close to one another as a group and partake in communal behaviors. To attract the martin, you should have a minimum of four cavities, or houses. Many birdwatchers want to build colonies of purple martins in their backyards. This is best done with six to twelve cavities.
The purple martin house should be mounted on a pole at a minimum of 12-18 feet from the ground. For the best security of the pole, setting it in concrete is recommended. Place your purple martin house within 100 feet of your own home. The purple martin enjoys the sights and sounds of people.
The Right House and Accessibility
The purple martin house should be accessible to you. You must be able to raise and lower it vertically in order to remove competitor nests. Starlings are known predators of the martin, often trying to build their nests within the martin house. This poses a threat to both the martin and its young. There are pulley systems available so that you can lower the nest to clear out any predator’s nests.
The purple martin house can be made of aluminum, heavy duty plastic or wood, but it must be white in color. White reflects heat to keep the temperatures cooler during the hot months. Wood that is 3/4 inches thick will also do the job of keeping the house insulated against heat and cold. If you prefer to buy a wooden purple martin house, keep in mind it should be made of untreated wood. Cedar, cypress, and redwood are all good choices for the purple martin house.
The Entryway and Compartment Size
The purple martin house entrance is another important consideration. The entrance holes should be round and range between 1 inch to 2 and 1/4 inches. Anything larger than this entrance size puts the martin in jeopardy with predators—hawks, owls, raccoons, and snakes.
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The purple martin house’s compartment size is also important. Larger compartments are the best choice as they offer protection from both predators and the elements. They also offer nestlings more comfort as the compartment will be home to not only the parents, but as many as six grown nestlings. A compartment with a generous amount of room also helps the nestling keep cool in hot temperatures. Nestlings who are uncomfortable or too hot inside the compartment have been known to jump out of the nest before they are ready, with fatal consequences.
Leaving the floors of the compartment natural or with a texture as opposed to smooth is vital to nestling development. Studies have found that slippery floors have affected the development of nestlings’ legs, resulting in permanently spread legs, a condition that is considered a fatal abnormality.
A Note for New Purple Martin Landlords
The purple martin is a people bird. It enjoys the sights and sounds of human habitation. For the new purple martin landlord, attracting a pair of purple martins in order to start their colony can take time—sometimes years.
Even after providing the right purple martin house and the right conditions, your first attempt may fail to attract any martins. Take heart. These birds look for housing continually throughout the season. What you must do is prevent other birds from using the housing you have created for the purple martin.
Be sure to regularly check the cavities for intruder nests. Doing so will assure you that the house is ready for the purple martin at any time. Allowing other birds to nest in the house will guarantee you don’t get the birds you set out to attract.