Dickcissels are fickle about breeding grounds, descending on a grassland in huge numbers to fight for territories with the best seeds and insects one summer and then avoiding that same grassland completely the next summer. This unpredictability makes studying the cause of population declines—partly driven by habitat loss and degradation—in these stout grassland birds difficult.
That’s why it’s so exciting to welcome a returning breeding population of dickcissels each year at Riverby Ranch, part of RES’ nearly 17,000-acre Bois d’Arc Lake Mitigation project in north Texas. And according to researchers studying bird populations at Riverby Ranch, it’s a good sign that this mega-scale restoration is working.
Monitoring birds, measuring restoration success
The five-year restoration of Riverby Ranch, completed in 2022 and now in a 20-year monitoring and maintenance phase, is the largest permittee-responsible restoration of its kind in North America. As a mitigation project for a new reservoir nearby, the former pastures and croplands were restored to their native state, creating a mosaic of wetland, grassland, and forest habitats for wildlife while satisfying the environmental permits for the Bois d’Arc Lake reservoir project.
By rebuilding the food web and restoring the conditions needed for breeding success, RES has created habitats that dickcissels—and dozens of other documented bird species—find worth fighting for and returning to.
Understanding what success looks like for a restoration project of this size requires specific research. To gather the data needed to measure its success by one key metric—the impact on bird populations—RES worked with faculty and students at the University of North Texas (UNT). This mutually beneficial partnership allowed RES to help sponsor master’s thesis work by UNT students while gaining valuable research insights into the birds of Riverby Ranch.
“In some regards, the best indicator of whether a restoration is successful is the bird life and animals that it attracts,” said Jim Bednarz, senior lecturer at UNT. “If the ecosystem is functioning properly, you're going to get a diverse community of animals and birds. So we're specifically looking at the bird communities, which are considered the top-level predators or the apex predators. If the apex predators are healthy, then that's a good indicator that the entire ecosystem is functioning and healthy.”
Two summers and more than 100 bird species
One master’s student, Tessa Boucher, agreed to dedicate two summers to monitor changes in the avian species composition over time at Riverby Ranch. Her research included two studies: comparing how the prairie grassland and wetland bird populations on Riverby Ranch are changing over time, and how they compare to neighboring areas that are not being restored.
To rigorously track bird sightings, Tessa defined 25 transects, each with four to six monitoring points over 1,000 meters. For two summers, Tessa walked each transect several times. Her research has confirmed some very encouraging news about the return of the bird population to Riverby Ranch, observing more than 100 species of birds, many of which are species of high conservation concern in Texas.
“I have observed many different signs of successful reproduction out here, especially in the dickcissel populations,” Tessa said. “This is great news, because they are a species of concern due to habitat loss, especially in terms of their habitat for breeding. I've also seen some umbrella species out here, like the upland sandpiper, the fact that they're here shows that the ecosystem is functioning and as a habitat is suitable for many other birds as well.”
Sighting multiple umbrella species means the many other species that make up the ecological community of its habitat can also thrive alongside them. The success of these bird species depends on the availability of the foods they eat, protective cover from predators, and suitable nesting conditions—all things provided in the restored habitats at Riverby Ranch.
Supporting birds at Riverby Ranch and beyond
The scale of the restoration at Riverby Ranch and the early avian success demonstrated throughout its grasslands and wetlands show that birds like the dickcissel will have a place to call home, year after year.
The foundation of the restoration was understanding and retooling the hydrology on the ranch, which worked hand-in-hand with replanting wetlands, grasslands, and forests. While wetlands and grasslands come in quickly, the forests will take years, or even decades, to fully mature. The researchers expect to see a greater density of species migrate through, breed, or make year-round homes in the protected habitats of Riverby Ranch in the coming years.
There is so much to be learned on a restoration site this large, and the research findings from Tessa and the UNT team will be shared with the ecological and educational communities at large to benefit future restoration projects—and future generations.
Key Takeaways