Throughout those years, Christopher Hecksher, a professor of environmental science at Delaware State University, immersed himself in surveying the park’s wildlife, expanding the understanding of its biodiversity. He would collect nighttime recordings and then work to differentiate the diverse chirps and sounds to aid in species identification.

“I did a survey over the last couple of years primarily to try to determine the presence or absence of the black rail, which is a very rare and secretive marsh-inhabiting bird,” he said. “At the same time, I was attempting to document other secretive birds that aren’t easily observed on the preserve.”

In addition to the black rail, Hecksher was successful in finding some of those other shy species that like to hang out in high salt marshes, known as brackish marshes.

“On the recordings, we did hear pied-billed grebe, American bittern, common gallinule. We did hear sora, which is another closely related rail.”

They also identified clapper rail, king rail and Virginia rail in the marsh.

Hecksher noted a test like this had never been done before. He said it’s crucial work due to the potential threat to species like the black rail. The find could result in increased protection measures for such endangered species.

“[The black rails] were not listed as federally endangered but they were listed as federally threatened, which is the highest level in terms of protection,” he said. “The Eastern population of black rail did warrant some federal oversight in the sense of, it could in the future — if we don’t manage our wetlands properly or if climate change accelerates that sort of thing — it could be in danger of becoming extinct.”