Saturday, June 6, 2020 – Purple Martins

I walk by a yard with a martin house. According to Wikipedia, martins make their nests in cavities, either natural or artificial. In many places, humans put up real or artificial hollow gourds, or houses for martins — especially in the East where purple martins are almost entirely dependent on such structures. Early reports say that the Choctaw and Chickasaw tribes mounted gourds on the branches of bare saplings to attract purple martins. Western birds often make use of natural cavities such as old woodpecker holes in trees or saguaro cacti. To prevent larger birds from using martin houses, the entrance hole should be approximately 2 1/8 inches.

Per birdwatching.com’s article “How to Succeed as a Purple Martin Landlord,” here’s what purple martins need:

Colonial living

Purple martins nest in colonies of two to 200 pairs. So, give them clustered housing. You can start with three or four units and add more as your colony expands. The best thing to potential nesters is martins already nesting there. That's why it's crucial to make the new housing as ideal as possible, in order to get that all-important first pair of birds.

House of wood, gourd, plastic or metal

Purple martins are not too picky about the material for their birdhouses. Many kinds of purple martin houses are available. Here are some possibilities:

• Grow your own birdhouse gourds.

• Build a wooden apartment house.

• Purchase ready-made martin houses.

• Hang plastic gourds that mimic natural ones.

Plastic "gourds" called SuperGourds make great purple martin houses. They come with rain guards and clean-out access doors. SuperGourds appeal strongly to martins and seem to result in excellent nesting success. And they certainly are beautiful!

Disney World purple martin colony

Home up high

A purple martin house must be mounted on a pole or post at least 10 feet high. Don't attach it to a tree, because cats and raccoons could easily climb to the nests, and purple martins won't move in.

Proper martin houses are on poles that can be raised and lowered vertically for inspection. Most systems utilize telescoping poles or a winch. A winch system is easier to use, because the martin houses can be heavy when they're full of nests and eggs or babies.

A house with a view

Location is crucial for purple martins. Their houses need to be in an open area so they can sail straight into the houses from at least two directions. Put their house in the middle of your biggest open area.

They don't want to maneuver through trees or dodge telephone wires. No trees taller than the height of the martin house should be within 60 feet of the colony.

Where they can see you

The purple martin house should be close to your own home. Purple martins want to see people near their nests. They know that human activity offers them protection against predators.

Disney World EPCOT

Near water

The birds will fly a couple of miles to water if necessary, but they prefer to nest within a half mile of a lake or other water. People in the small town of Fairfield, Iowa, got martins even though there was no water in sight. But the town reservoir was only half a mile away.

Roomy rooms

Each purple martin compartment should be at least 6" x 6" x 12." Some martin houses are sold that are only 6" x 6" x 6." Research shows that this is too small for purple martins to lay a full clutch of eggs —up to seven — and raise the young.

Good management

Don't buy a purple martin house if it doesn't provide for you to open it up and clean out the compartments. You need to be able to get in there and make sure there are no house sparrows or starlings nesting inside. All good purple martin houses allow access to the landlord!

Don't be intimidated by the task of examining the nests. The purple martins won't mind in the least. Remember, they like people. They will have greater nesting success if we do our job. Besides, it just about the most fun thing in the world to look into the martin nest and see the baby birds inside.

Starling and house sparrow

Safe from enemies

A purple martin's worst enemies are two aggressive, non-native birds that have been introduced into North America — the house sparrow and the starling. Both covet purple martin houses and will take them over if the landlords let them. The house sparrow and European starling are known to kill adult martins, take over the nest and remove eggs or remaining young. If the martin house is to succeed, the landlord must check the house every few days (or even daily in some cases) and remove any starlings or sparrows who try to build there.

For protection from cats, raccoons and snakes, a purple martin house requires a predator guard around the pole near its bottom.

Male and female purple martins

Purple martin description

According to Wikipedia, the purple martin is the largest swallow in North America. Despite their name, purple martins are not truly purple. Their dark blackish-blue feathers have an iridescent sheen caused by the refraction of incident light giving them a bright blue to navy blue or deep purple appearance. In some light they may even appear green in color. Adult males are entirely black with glossy steel blue sheen, the only swallow in North America with such coloration. Adult females are dark on top with some steel blue sheen, and lighter underparts. Purple martins are known for their speed, agility and characteristic mix of rapid flapping and gliding flight pattern. When approaching nesting sites, they will dive from the sky at great speeds with their wings tucked.

Migration

Purple martins’ breeding range extends from central Alberta down through the eastern United States. Subspecies breed in Baja California, Arizona and New Mexico. Most make a brief stopover in the Yucatán Peninsula or Cuba during pre-breeding migration to North America and during post-breeding migration before reaching their overwintering site in Brazil, Bolivia and parts of Peru. Martins generally migrate over land, through Mexico and Central America.

When not breeding, martins form large flocks and roost together in great numbers. This behavior begins just prior to the southern migration and continues on the wintering grounds. These flocks can be so large that when they take off from these roosts to forage, the activity is detected on Doppler radar as rings. Referred to as roost rings, they start small then get larger until the birds have spread out and the ring disappears.

Diet

Purple martins are insectivores, primarily feed by hawking, a strategy of catching insects in the air during flight. The birds are agile hunters and eat a variety of winged insects. Rarely, they will come to the ground to eat insects. They usually fly relatively high, so, contrary to popular opinion, mosquitoes do not form a large part of their diet. Recent research, however, does indicate that the purple martin feeds on invasive fire ants, and that they may make up a significant portion of their diet. When they encounter prey, they turn suddenly sideways or upward, speed up, and then flare their tails as they trap the insect. Martins pick up small bits of gravel to help them digest insect exoskeletons.

Vocalization

Purple martins are fairly noisy, chirping and making sounds that have been described as chortles, rattles, and croaks. The various calls are said to be "throaty and rich" and can be rendered as tchew-wew, pew pew, choo, cher, zweet and zwrack. The males have a gurgling and guttural courtship song, a dawn song and even a subsong used at the end of the breeding season. Tapes of purple martin songs are sold to attract martins to newly established birdhouses.

John James Audubon

Fun Facts About Purple Martins

According to Cornell University:

· The oldest purple martin on record was at least 13 years, 9 months old, banded in 1933 and found in 1947. It lived in Illinois.

· Putting up martin houses used to be so common that John James Audubon used them to choose his lodgings for the night. In 1831, he remarked, “Almost every country tavern has a martin box on the upper part of its sign-board; and I have observed that the handsomer the box, the better does the inn generally prove to be.”

· The purple martin not only gets all its food in flight, it gets all its water that way too. It skims the surface of a pond and scoops up the water with its lower bill.

· Despite the term "scout" used for the first returning purple martins, the first arriving individuals are not checking out the area to make sure it is safe for the rest of the group. They are the older martins returning to areas where they nested before. Martins returning north to breed for their first time come back several weeks later. The earlier return of older individuals is a common occurrence in species of migratory birds.