How to build purple martin house, conserve birds in Kentucky

A small blue-purple bird often seen throughout the state during the spring has started to trickle back into Kentucky, but birdwatchers may be seeing less of the species in the future.

The world’s population of purple martins has declined steeply, and the species’ survival depends on humans providing housing for them, Joe Siegrist, president and CEO of the Purple Martin Conservation Association told the Herald-Leader.

“Over the last 50 years, we’ve lost about a third of all the purple martins in the world. The populations have declined that much,” Siegrist said.

Purple martins eat a quarter of a trillion flying insects each year, including pests to humans and agriculture. But the birds are no longer able to meet their nesting needs in nature, so their conservation requires humans to step up.

Female and immature male purple martins are “large and chunky,” often gray and duller than their adult male counterparts. Adult male purple martins have dark blue-purple coloring with brown or black wings.

Many purple martins winter in the Amazon and fly to the U.S. in early spring, according to the National Audubon Society. Southern states may see them in February, while those in the western U.S. might have to wait until April or May to catch a glimpse. The birds may fly over Mexico and through Central America on their migration journey.

“Purple Martins are probably leisurely migrants that fly only during the day and forage as they go,” the National Audubon Society website reads.

The first purple martins of the season have started to trickle in to Kentucky, and now is a great time to build housing for them, Siegrist said.

How did purple martins get in this situation, and what can Kentucky residents do to promote the species’ survival? Here’s what to know.

How did purple martins become reliant on humans?

Before European colonization, purple martins nested naturally in old woodpecker holes, cliff holes and rock piles. Indigenous communities also provided housing to the birds through hanging hollowed-out gourds.

“Up until European settlement, you know, the birds had the best of both worlds,” Siegrist said. “They were nesting naturally and they had these artificial nests that were provided around human settlements.”

Colonization and westward expansion led to deforestation across the U.S., severely reducing the number of available nesting sites for purple martins.

Natural nesting sites that survived were taken over by English house sparrows and European starlings around the turn of the 1900s, Siegrist said.

To provide nesting sites for purple martins, you can put up a multi-compartment house or gourds.

Those with open backyards are good candidates to put up purple martin housing. It’s best to avoid placing houses near large trees, as birds of prey may stop by and they can threaten purple martins.

“Kentucky is a great place to put up a purple martin house,” Siegrist said.

Purple martins like to nest in groups, and you could offer six to 12 cavities when starting out a colony.

One fun factor of making housing for purple martins is you’ll likely get to see the same birds return each year.

“It’s an incredibly rewarding hobby for people, you really can get back in touch with the natural world through having one of these in your backyard,” Siegrist said.

Siegrist recommends people check in on their purple martin colonies and keep track of what they see. You can perform a nest check by lowering the housing and looking in all the cavities at midday or the afternoon, avoiding checks during early morning hours and in the evening.

You don’t need to set up a bird feeder or bath to attract purple martins, as their diet relies on flying insects.

“Very rarely is there a species that you can conserve so simply by just putting up a birdhouse in your backyard,” Siegrist said.

The Purple Martin Conservation Association offers additional tips on designing purple martin housing online at purplemartin.org.

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