Bird Notes from West Houston

Tuesday, January 24, 2006

Species Profile - Purple Martin

Nearly seven years ago, I was introduced to the joys of being a Purple Martin landlord. Well, it wasn't my colony. I began working at the Wild Birds Unlimited in Dallas where there was a very active martin colony and was able to take an active part in performing nest checks and keeping records of the martins. Before that, the Purple Martin was a spring migrant that lacked the color of the other migrants and was only a "tick" on my springtime list. In the spring of 1999, my view changed completely about Purple Martins. I would now list them as one of my top five favorite birds. I find myself this time of year looking up a little more often and straining my ears to catch even the slightest hint of the martins' song announcing their return.

The Purple Martin is North America's largest swallow species. From beak to tail, adult martins measure eight inches and have an eighteen inch wingspan. Adult males, or ASY (after second year) males, look black much of the time unless the light reflects just right off their feathers showing the purplish iridescence for which they are named. Females, as in most bird species, lack the color of the male. Females plumage will be black to dark gray on the back with dingy gray on the breast and belly. She will have a gray collar and gray forehead. Young males, or SY (second year) males, will look very similar to females.

Martins almost exclusively nest in man-provided housing in the eastern United States. Before man-made housing was available, martins nested in old woodpecker holes in trees. Deforestation significantly reduced the number of trees available. Native Americans would put up hollowed-out gourds to attract the birds because of their insect-eating nature. That seems to be where the transition from nesting in natural sites to man-made houses occurred. Purple Martins in the western United States still use natural nesting sites. Nesting material consists of leaves, mud, twigs and feathers. Many times a mud barrier will be built at the front of the nest. Both the male and female take part in nest construction. The eggs are white with no markings. Three to seven eggs are laid. The female incubates the eggs for fifteen to eighteen days. When the babies hatch, they are altricial (eyes closed, featherless, immobile and dependent upon the parents for food.) The young will fledge after 26 to 31 days. Both the male and female take part in feeding the young. Normally martins have one brood per year, although some have been documented having two broods in southern states. In the eastern United States, martins will nest in colonies, so having more than one compartment available for them will greatly increase your chances of attracting these beautiful birds.

Martin habitat is especially important when considering where to place a house or gourd rack. Martins require at least 30 feet radius around their housing free of anything that stands as tall or taller than the housing (i.e. your house, trees, large bushes, etc.) Most other birds like to be as far away as possible from human activity when nesting. Not so with the martin. Research has shown that martins are much less likely to use housing over 100 feet from a human dwelling. Your chances of attracting martins increase if you are near a pond or lake.

Martins return to the same colony year after year. A man who banded Purple Martins in Duncanville told me one time that he had a male martin return to the same house and same compartment for fourteen years! As long as there is not a major disruption in nesting, the martins you have nesting at your colony are likely the same ones that nested there the year before. While the adults return to the same colony, less than 10% of the young that hatch in a colony will return. Those birds will start new colonies or join other established colonies.

Purple Martins have the reputation of being voracious mosquito eaters. Unfortunately for those of us in Southeast Texas, research hasn't backed that up. Usually no more than 3% of the martin's diet consists of mosquitoes. What the martins do eat are insects that fly hundreds of feet in the air such as dragonflies, butterflies, cicadas, flying ants, bees, wasps, damselfies and mayflies. Any airborne insect is at risk of becoming a meal for a Purple Martin.

Martins usually arrive in Southeast Texas during the first week of February. Many of those birds are migrants heading further north. Many will be returning to their colonies here to begin establishing their territory. Typically the SY birds will return four to six weeks after the ASY birds. If this is your first year to have martin housing up, have it ready by the first week of March since the SY birds will be the ones to set up a new colony. Check the website for the Purple Martin Conservation Association (link to the right) to check the status of the arrival of martins in North America.

Being a Purple Martin landlord has responsibility beyond putting up housing the in proper habitat. House Sparrows and European Starlings are non-native nest competitors and will nest in martin housing if they are allowed. I have personally witnessed the damage done by these birds to martins, both adults and chicks, and eggs. At the least, their nesting material should be removed when they start building. Sparrows and starlings use a lot of grass in their nest easily distinguishing it from a martin's nest. Many traps are available for martin landlords who choose to remove the sparrows or starlings from their property.

I have had people ask, "What is the big deal about Purple Martins?" I used to ask that before I had experience with them. My answer is usually very vague because I believe you just have to experience martins at a nesting colony to understand. If you have too many trees around for martins, hopefully you know someone who has them and can take part with them while the martins are here. Some people will purchase martin housing to put up on golf courses, at churches or parks and maintain them. I wish everyone could experience the joys of the Purple Martin as I have.

- Paul


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