Purple Martins

(Progne subis)



For centuries people have been enamored by the Purple Martin.

History shows us that the American Indian set up gourds and other materials for these special birds to nest in.

Why not, they eat copious amount of insects and these birds are a joy to have around.

While they do eat some mosquitoes, it is not the thousands you are led to believe by manufacturers and retail stores.

These are larger birds and they need larger insects like grasshoppers, wasps, dragonflies and so on.

Not to mention, martins and mosquitoes are out at different times of the day and fly at different levels.

Still, any one that has witnessed a colony of martins wished for their own.

Beware, hosting a martin colony is a responsibility, but one well worth the efforts

Male Purple Martin

Description:

The Purple Martin is the largest swallow (Family Hirundinidae) in North America, and like other swallows, they are sleek-bodied, aerial insect hunters with long, pointed wings and a wide, gaping mouth for scooping in insects.

Male Purple Martins are solid black with a blue, violet, or purple iridescence that is visible in direct sunlight.

It takes two years for a male to reach his adult coloration, and until then, the sub-adult male is grayish below with variable spots and patches of purplish black.

Although both the adult females and the immatures are mottled grayish below, the adult females are purplish black above, while the immatures are a mostly non-iridescent dark grayish above.

When seen only from below, the females can be difficult to distinguish from the immatures.

Distribution and Breeding Habitat:

Martins are a migratory species that breeds along the West Coast and in the eastern and central portions of the United States, in parts of Canada and Mexico.

While martin populations have grown in the East, their numbers have declined in the middle of the United States.

This species nests in open and semi open areas, including savannas, cultivated lands, fields, parks, pastures, near lakes and marshes and in towns and suburbs.

These birds can reach fairly high densities when nest boxes are present; however, in other areas, they can be completely absent.

In the West, martins are less likely to inhabit nest

boxes, relying more heavily on natural cavities and old woodpecker holes found in cactus and trees however, they will nest in gourds and supplied single-unit houses on the West Coast.

Diet:

Female Purple Martin

Martins are obligate, aerial insectivores; they feed in flight upon flying

insects such as wasps, moths, flies, grasshoppers, bees, and ballooning spiders.

They also feed on midges, dragonflies, damselflies, cicadas, stinkbugs, beetles, and butterflies.

As mentioned above, they are not the mosquito specialists that martin-house manufacturers would have us believe.

They forage high above the ground and over water, in loose aggregations.

Pair Formation and Territoriality:

Usually the first to return to the breeding site, male martins immediately choose and defend a nest site.

Females select their mates based upon the nest site and upon the male himself.

Martin Colony

Purple Martins are monogamous, but both sexes are highly promiscuous.

Once a pair bond is formed, both sexes defend the nest site intensely.

Martins nest in colonies, but members of the breeding colony are not related.

Nesting:

Purple Martins are swooping birds and require nesting sights at least 12 feet off the ground and in open spaces to allow these birds to freely come and go.

A cavity nester, that will use apartment type birdhouses.

Loosely made nest of grasses, twigs, bark, paper, string; egg cup lined with fine grasses and decorated with fresh leaves, 4-5 eggs; pure white and slightly glossy.

The breeding season begins in late March in the southern part of the range, but not until late May or early June in the northern parts. (In Florida, however, nest building can begin as early as February.)

As with many native cavity-nesting species, Purple Martins compete with House Sparrows and European Starlings for nest sites.

In many regions, such as the eastern United States, martins are extremely dependent on human-provided nest boxes.

Nest building starts about a month before the first egg is laid.

Initially, pairs may begin to build in more than one cavity.

Eventually one cavity is chosen, and the male and female build a nest made of grass, stems, twigs, straw, bark, leaves, and mud.

The nest cup is lined with fine grasses and green leaves.

Fresh green leaves are brought regularly until the eggs hatch.

No one really knows for sure why martins do this.

The nest also has a mud or dirt rim that may prevent the eggs from rolling out and deter rain from coming in.

Incubation and Care:

Females incubate their eggs for 15 to 16 days. When females are absent from the nest, males may sit on the eggs or sit at the nest entrance to guard it.

Males may also stand over the eggs to prevent cooling.

Hatching is asynchronous; that is, all of the eggs don't hatch at once.

Hatching may occur over two to three days.

Both adults feed and care for the nestlings.

The young fledge after 26 to 32 days; sometimes they stay in the nest longer.

As the young leave the nest, the parents try to keep their brood together, but family mixing within the breeding colony often occurs.

Sometimes the fledglings are mobbed by members of the colony.

The reason for this is uncertain.

(Purple Martins in Arizona nest in Giant cactus).

Some researchers believe this prevents the fledglings from imprinting on the colony site.

Others believe it is to keep them from coming back to steal incoming food from younger colony mates in neighboring compartments.

The fledglings remain dependent upon their parents for up to two weeks after leaving the nest.

Purple Martins have one brood per season.

Two broods during one breeding season is considered rare, though they will re-nest if nest failure occurs early in the nesting cycle.

Winter Movement and Dispersal:

After the breeding season, Purple Martins assemble into large flocks.

Eventually these flocks migrate to parts of South America, including Brazil, the Amazon basin, Bolivia, and Paraguay.

The Purple Martin Conservation Association reports that approximately 10% of juvenile birds returns to their natal colony.

Another 30% returns to the general vicinity of their natal colony.

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More Backyard Birds

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