Purple Martins are actually members of the Swallow family, which includes the familiar Barn Swallow and also Swifts such as the Chimney Swift. Like the other members of this group—as well as many other songbirds—their numbers are dropping in a scary way. No one is quite sure why, but there are several theories, including habitat loss on wintering grounds and breeding grounds, migration interference, lack of insects due to broad-spectrum pesticide use, and over-predation.
Purple Martins are attractive birds, and we love to watch their aerobatics as they swoop and dive in search of insects. If you succeed in attracting them with birdhouses, they will give hours of entertainment. One side benefit is the number of flying insect pests they consume. The males are dark blue and iridescent, while the females are duller in color, being more brownish or gray, with paler or off-white lower belly, and purplish patches on the upper wing, back and crown.
These birds are high fliers, and though they are our largest swallows, that’s sometimes hard to tell in flight. Martins take all their food on the run, catching flying insects in mid-air, including larger prey that smaller swallows will pass up, such as dragonflies. They even drink while in flight, by skimming over ponds and dipping their beaks in the water as they fly.
More About Purple Martins
Purple Martins breed in temperate North America, and winter in South America, mostly in Brazil. During breeding season, in the East, the Purple Martin nests in colonies, using man-made nesting boxes. These houses may be called martin condominiums, because they are made to house multiple pairs in separate “apartments.” In fact, nesting boxes with less than four apartments are not attractive to the Purple Martin, and six apartments or more are better still. The more the merrier!
Interesting to note that in the West, however, martins still use natural cavities as nesting sites, much as they always have done. They take advantage of old woodpecker holes in trees, or natural cavities formed in rocks or caves. These western Purple Martins may also choose single nest boxes.
Why the difference? It is a highly unusual phenomenon to see a species change its nesting habits entirely. In fact, they have become totally dependent on human constructions for their nesting habits, as mentioned in the video above. There are only three species who have done this, and all are in the swallow family. They are:
- The Chimney Swift. They used to nest in enormous, hollow trees, but made the change to nest in chimneys, especially the big old brick industrial smokestacks of the past. Their numbers are now in decline, and one reason is that the old style smokestacks are disappearing. They just can’t seem to remember what they did before humans went industrial! But even if they did remember, huge ancient hollow trees are just really hard to find now, even rarer than huge old smokestacks.
- The Barn Swallow. As with the Chimney Swift, the name gives away the nesting preference. Once upon a time, Barn Swallows nested in rock crevices and in the mouths of caves. Their mud and straw nest constructions stick just as well to the rafters of barns however, and they made the switch as agriculture spread throughout North America. Problem is, big old barns with high roofs for hay storage are also getting rarer. Barn Swallows will choose smaller buildings as well, of course, but unlike the old barns, with large doors for harvesters to drive through, open shutter air vents, hay doors and so on, many smaller outbuildings on farms have few doors. What’s more the doors they do have are often closed, and the windows have screens, which won’t work for the parent birds who have to come and go many times a day.
- The Purple Martin. Apparently the native Americans started hanging gourds on poles for the Purple Martins, probably several thousand years ago. They must have been as fond of them back then as we are today. The idea spread and was a huge hit with the birds; so much so that the birds abandoned the old ways entirely. Along with the preference for man-made housing, the Purple Martins also have the requirement to nest in colonies now as well, unlike their western counterparts who will nest in a single-family dwelling.
Purple Martin Birdhouse Basics
Many people put up birdhouses. And there are a number of native species here in North America who will use them. Tree Swallows and Wrens are fairly easy to attract to a nest box. But also Chickadees, Downy Woodpeckers, Wood Ducks and even some owls such as the tiny and hands-down cuteness winner the Saw-whet Owl, are known to use the type of nest box designed to their particular needs.
And by needs, we are talking about the overall size, the height from the ground, the shape of the box, the habitat or site, the dimensions outside and of the interior as well, and very importantly, the size of the entrance hole.
When you are considering setting up birdhouses, there are the non-native species such as the Starling and European House Sparrow to think about as well. These are considered to be invasive pest species, and will out-compete many of the natives when it comes to nest sites. Including nest boxes. This is as true of Purple Martin housing as single-family nest boxes.
Wrapping Up For Now
The Purple Martin, as discussed, needs a community situation to be happy and raise a family. Maybe they feel there is safety in numbers. At any rate, all housing for the martins needs to offer many rooms. There are many styles to choose from as well, and it can get very complicated being a Purple Martin landlord!
Along with the challenge of pesky invasive birds, there are many other factors to consider, including how to protect nesting birds from predators who’d find them an easy and obvious target in their community housing. There are solutions; read more about how to set up Purple Martin birdhouses here.