If You Build It, They Will Come!

By Christine Zamora

This year was surprisingly successful for the Purple Martin colonies that Alachua Audubon monitors. AAS contributed to these exciting results by installing three new gourd systems, complete with predator guards, at suitable locations in the fall of 2025. The new housing structures make a total of 12 AAS-managed rack systems, offering a grand total of 120 gourds for the martins to call home. The gourds are located on four sites: Sweetwater Wetlands Park (3 racks/28 gourds), Prairie Creek Preserve (2 racks/16 gourds), Orange Lake Overlook (2 racks/18 gourds), and Lake City Wetlands (5 racks/64 gourds). The systems at Orange Lake Overlook are jointly managed with Marion Audubon Society, while the systems at the Lake City Wetlands are largely managed by Four Rivers Audubon.

So what’s the good news? The new martin houses at Orange Lake Overlook and Sweetwater Wetlands Park achieved 100% occupancy! This is a remarkable success for any Purple Martin landlord. Generally, new housing is occupied slowly, usually by a few pairs of pioneering martins during the first year, with following years bringing greater occupancy. Achieving 100% the first year doesn’t happen often, so you can imagine our surprise to discover each gourd occupied! This immediate success rate highlights the critical need for housing – Purple Martins depend on it. Populations east of the Rocky Mountains rely almost exclusively on artificial structures to survive and fledge young. As the story goes, build it and they will come.

Location matters nearly as much as the housing itself. Selecting the right spot for gourds plays a critical role in Purple Martin nesting and fledgling successes. For instance, in this year of unprecedented drought conditions, we were concerned about food availability. Drought affects aquatic insect populations that are the primary food for martins and their young. Would there be enough insects to successfully rear the babies? As water bodies dried or shrunk throughout the county, birds endured at the gourd sites, likely due to their proximity to water and a healthy supply of food. The site selection at Sweetwater Wetlands Park and Orange Lake Overlook must have been especially favored by Purple Martins given the early spring nest checks that revealed the housing at full capacity with 93 young and 18 eggs at Sweetwater Wetlands Park, and 66 young and 17 eggs at Orange Lake Overlook, a total of 194 young and eggs.

Protection from predators also contributes to success. While we had brag-worthy results at two sites, the gourds at Prairie Creek Preserve were less successful, likely due to a fallen predator guard. We don’t know how long the guard was on the ground before it was reported and reinstalled, but we suspect its temporary absence had an impact. When nest checks were conducted in early spring, the systems at Prairie Creek had only 19 eggs and one young. We suspect the guard came off during a critical period, increasing vulnerability to predators and reducing the colony’s success. Predator guards are essential to gourd system installations. Purple Martins are resilient, and with the predator guards back in place, we expect nesting success next season.

Thanks to the support of AAS members, the Purple Martin colonies will hopefully continue to succeed and grow, and we can share more stories like this. Build it… in the right location and with protection from predators… and they will come.

From The Crane, Vol. 67 (6) July-August 2026

Hoping that Purple Martins would nest at the Lake City Treatment Wetlands, Alachua Audubon and Four Rivers Audubon teamed up in 2018 and purchased and installed an eight-gourd nesting system. The Purple Martins promptly arrived, moved in, and raised young in all eight gourds. Our two Audubon chapters expanded the housing complex by installing a larger, 12-gourd system in 2019, a third on in 2021, and a fourth nesting system in 2023.  Now with 44 nesting gourds, the martins at the Lake City Wetlands have plenty of nesting opportunities, which they took advantage of in 2024 by fledgling over 150 Purple Martins!

Purple Martins at Sweetwater Wetlands Park were not as quick to nest in the gourds as those at the Lake City Wetlands. But the nesting success has increased slowly at Sweetwater, and in 2024, all seven nesting gourds contained baby martins. To capitalize on this success and to increase the colony size, Alachua Audubon received permission from Sweetwater staff to install a second nesting gourd system.  This new unit was installed in December 2024 and is ready for the Purple Martins to return in early 2025.

Alachua Audubon has expanded the network of nesting gourds by installing eight-gourd systems at Prairie Creek Preserve and at Orange Lake Overlook, both properties owned and managed by Alachua Conservation Trust; as of spring 2025 both systems have been occupied!

   

How exciting to know that even with an expected level of predation and mortality, these colonies of stunning, vivacious, and aerobatic swallows can fledge well over 100 Purple Martins per nesting season. (Photos by Tedd Greenwald)

AAS volunteers Winnie Lante and Rick Williams have researched and ordered several of the systems, organized and installed the arrays, and engineered solutions to make the systems safer and more functional. Tedd Greenwald and Mary Ellen Flowers have helped with installations and checking the nest boxes for nests, eggs and hatchlings.

Gourd installation photos from Lake City Wetlands in 2018 below.