UPDATE: I feel like a proud Grandpa. We have at least one baby Martin in the Purple Matin House. I took a picture of him which you can see below. It is not the best shot as the Martin House is over 10 feet above the ground on a pole and my digital camera is not too good on long shots (Nikon COOLPIX 990). I, of course, also did not want to climb a ladder to get a closer snapshot of the chick as the parent birds are in the area and would likely get upset if I came too close to the babies.
What is a Purple Martin (Progne subis)? And why do you want to invite them to your garden? Purple Martins are the largest member (to 8 inches long) of the swallow family of birds. They are famous for a number of things: 1) their prodigious appetite for bugs, 2) their aerial acrobatics, 3) their close association with humans, and 3) their yearly migration over land from Canada in the summer to Brazil in the fall.
While certain Purple Martin house manufacturers make big claims for these birds’ appetites for mosquitoes (a popular urban myth also), studies have shown that mosquitoes comprise “less than 3% of the martin's diet, by volume, and these studies involved the much larger, day-flying salt marsh mosquito, found only in a narrow band of habitat along coastal estuaries.” (Source: http://purplemartin.org/update/ThirtWays.html). But Purple Martins do eat only flying insects, which they catch in flight including dragonflies, damselflies, flies, midges, mayflies, stinkbugs, leafhoppers, Japanese beetles, June bugs, butterflies, moths, grasshoppers, cicadas, bees, wasps, flying ants, and ballooning spiders so they are awesome flying insect controllers in general.
Why would you want to buy and install a Purple Martin house? Well, these are really sleek looking birds. Adults have a slightly forked tail. Adult males are entirely black with a glossy steel blue sheen. Adult females are dark on top with some steel blue sheen, and lighter underparts. Subadult (first year birds ready to breed) females look similar to adult females minus the steel blue sheen and browner on the back. Subadult males look very much like females, but solid black feathers emerge on their chest in a blotchy, random pattern as they moult to their adult plumage. Purple Martins breed in North America almost exclusively in human provided nesting sites (i.e. specially made Purple Martins houses and plastic and natural gourds). Purple Martins are now totally dependent on human provided nesting sites for breeding. According to purplemartin.org “the martin would rapidly disappear from eastern North America if we were to suddenly stop providing housing for it.”
Purple Martins are probably one of the tamest wild birds because they have been catered to by humans longer than any other North American bird species. Thousands of years ago, Native American Indians attracted Purple Martins to their villages by hanging up hollowed-out gourds for them. Gradually this tradition spread to many other North American tribes. Then in the 1600's, when European colonists began arriving in the New World they also adopted the tradition of providing housing for Purple Martins (Source: http://purplemartin.org/update/ThirtWays.html).
Purple Martins are a wonder to behold in flight. Fighter jet builders would love to construct their planes to do the aerial acrobatics that these birds can achieve. I do not think that there is anything more exciting than seeing a Purple Martin come in for a landing to its housing in the evening. First they circle a couple of times then fold in their wings and make a high speed dive to the bird house and come to an immediate stop atop their perch.
To hear the song of a Purple Martin, click here http://en.wikipedia.org/wiki/File:Progne-subis-001.ogg
Below are a couple of pictures of my Purple Martin housing. As you can see from the first picture I had to do some cleaning to evict the wasps living in the martin housing. I then raised the bird house up on the adjustable steel pole to about 10 feet in height. I hope to see my Purple Martin tenants soon. To see where the Purple Martins are on their flight back to North America, visit the “Scout Arrival Report”. While you are there explore the Purple Martin.org web site for tips on how to attract these wonderful birds to your yard.