Stephanie Walton, Chief of Marketing & Communications
The conservation staff at Summit Metro Parks (SMP) is always up to something new and exciting. From releasing rare turtles back into the wild, to raising honeybees, to studying the behavior of bats and coyotes, their work routinely uncovers new information that informs ecosystem management and species protection. But one recent discovery stands out from the rest.
While studying migrant bird species in Deep Lock Quarry Metro Park and the Cuyahoga Valley, former SMP biologist Ryan Trimbath found the key to unlocking a decades-long mystery. Birders had long suspected that cerulean warblers and parula warblers were mating to create hybrid birds. Although many observers had seen birds that looked like a cross between the two species, or whose calls did not sound quite right, none of the birds in question had been captured for genetic testing.
“Documenting hybridization is important to help us understand speciation, evolution and conservation,” explained Trimbath. “Monitoring and tracking these populations helps inform management practices to protect the species.”
Cerulean warblers are a species of concern across their breeding range, with populations in Ohio declining nearly 75 percent since the 1960s due to habitat loss and fragmentation, as well as deforestation of their wintering grounds in South America. In at least one case, hybridization has resulted in the elimination of a species: blue-winged warblers replaced golden-winged warblers locally within 20 to 50 years of contact.
Trimbath’s three-year study, internally dubbed “The Secret Lives of Birds,” monitored the nest success rates of three species of forest-breeding songbirds: the hooded warbler, cerulean warbler and the wood thrush. During the course of his work, Trimbath was able to safely collect blood samples from two unusual-looking cerulean warblers in Deep Lock Quarry Metro Park. He then shared the samples with the Cleveland Museum of Natural History, where Dr. Andy Jones and Courtney Brennan conducted genetic testing that confirmed the birds were indeed cerulean/parula warbler hybrids.
“Finding these birds was by far the most exciting moment of my career — cerulean warblers are my favorite bird species, and studying their populations has been a side project of mine for some time,” Trimbath said. “I feel lucky to have been in the right place at the right time to notice the subtle variation in the song of the hybrid to detect this little bird that lives in the treetops.”
Migrant songbirds such as cerulean warblers visit local forests to breed every year, coming north from their winter grounds to capitalize on high-protein foods such as caterpillars, spiders, flies and beetles. Located in the Cuyahoga Valley, Deep Lock Quarry Metro Park and the entire surrounding Cuyahoga Valley National Park are noted Important Bird Areas (IBAs) and are an ideal habitat for these seasonal visitors.
“This project is an example of how park districts and related organizations often work closely together to advance ecological conservation,” said SMP Chief of Conservation Mike Johnson. “This discovery was made possible thanks to the collaborative nature of the Northeast Ohio scientific community.”
Trimbath is now employed by the Cuyahoga Valley National Park while he completes his Ph.D. studies at The University of Akron.
To learn more about the exciting work of the SMP Conservation Department, check out the Conservation Matters! exhibit on display now at the F.A. Seiberling Nature Realm Visitors Center, located at 1828 Smith Road in West Akron.
SMP offers 16 parks, 150 miles of trails and dozens of free programs each month. Additional information, including program details and center hours, is available at www.summitmetroparks.org.
This article was originally published by Leader Publications on June 28, 2019 and can also be viewed at www.akron.com.