The Purple Martin
Just like many folks across the South today, Native Americans placed hollowed-out gourds on poles to attract nesting Purple Martins which would then drive hawks, crows, and vultures from the vicinity.
Everyone loves Purple Martins. They are the first migrants to return to Louisiana after wintering in South America. Seeing this beautiful bird in early February or late January brings the realization that spring is in the near future.
The myth of martins eating “2000 mosquitoes a day” is just that. They forage at heights above a hundred feet where few mosquitoes are found. While they can eat mosquitos, martins prefer larger prey such as mayflies, moths, butterflies and dragonflies. They are insect eating machines and devour hundreds of flying insects a day.
Martins are graceful birds. They wheel and circle overhead with ease while nabbing flying insects and are fun to watch. Since martins are colonial birds, you never see just one, and usually many are chirping together on the telephone wire.
Adult male and female martins arrive at the colony site first. These early arrivals are known as ‘scouts.’ It was traditionally believed that these scouts flew back to guide other martins to the colony site. Now we know that the experienced martins arrive first to take possession of the choicest nesting sites before other birds show up.
Once the adult males arrive at the nesting site, they start to defend their territory. This nesting site usually is a commercial martin house with several compartments or perhaps a gourd. The males sing and announce their presence as the females arrive. The song of the martin is a cheery sound, and many purple martin landlords look forward to being serenaded every year.
Purple Martins typically return to the same nesting spot they used the year before, sometimes even the same nest compartment or gourd. Originally they nested in natural cavities such as old woodpecker holes or roof ledges. Natural cavities are important to martins. With a small bill, they are incapable of excavating cavities themselves. Once Purple Martins found nesting success with human supplied housing, they developed a preference for it—though west of the Rockies, in mountain populations and in the desert they still use natural cavities.
Martins are easily attracted to neighborhood backyards. Though they co-exist well with humans, they do have preferences for cavity location. The gourd or martin house needs to be placed far enough from a tree or trees to keep the martin safe from predators such as owls and hawks. Other birds, such as the European Starling and the House Sparrow, are opportunistic nesters and will compete for space in martin houses. Diligent martin landlords monitor and thwart any nesting efforts of these two introduced species to prevent injury to the martin nestlings or eggs.
In late summer when nesting is over, martins from a large geographical area congregate in big flocks. An area where I have seen this pre-migratory (or post breeding dispersal) flock gather is the south end of the Pontchartrain Causeway. In late July/early August, martins will start to roost under the causeway bridge.
They arrive prior to dusk and continually arrive until it is dark. Within that hour or so you can see thousands (approximately 10,000 birds last year) of martins flying across the water to gather under the bridge. By early September, all of the martins have left for South America.
Description: Males are dark blue-black swallows with long, pointed wings; short tails; small hooked bills and fairly small feet. Male Purple Martins are the only swallow with dark bellies. Female Purple Martins are duller with differing amounts of grey on their head and chest; females have a whitish lower belly.
When: Purple Martin scouts arrive in late winter; other martins return in spring and leave for South America in late summer.
Where: Semi-open country near water; farms; backyards if housing is provided.
Breeding: Strictly cavity nesters; swallows breed in colonies with many nests close together.
Feeding: Almost any type of flying insect including wasps, bees and winged ants; beetles and spiders have also been found to be part of the martin’s diet.
Interesting facts: The top flight speed of a martin is over forty miles per hour. The Purple Martin really isn’t purple but may appear to have a purple sheen in certain lights.
The Purple Martin Conservation Association provides information on martin care at purplemartin.org.