For birds, designations like state, federal, and private land have no meaning—good habitat is good habitat. Yet, despite this avian obliviousness, who owns land can have big implications for the bird habitat it contains, according to a new study.

To find out how the habitats of endangered wildlife are faring under different types of land ownership, Tufts University researcher Adam Eichenwald, along with data scientist Michael Evans from the conservation group Defenders of Wildlife, analyzed more than 30 years of satellite data to measure the amount of habitat lost by 24 imperiled animal species across the United States. Their findings, published in the journal Frontiers in Ecology and the Environment, revealed a stark difference: Species lost almost twice as much habitat on private land as on federally owned acreage—8.1 percent over that 30-year period, compared to 3.6 percent.

“I think the one thing that our analysis points to is the real strength of federal lands programs and federal regulations for providing real on-the-ground protections to habitat and the species that live in them,” Evans says.

To get a sense of habitat loss across the entire country, Eichenwald and Evans analyzed species that together represent all of its major ecoregions. Thirteen of the species studied were birds, including the Cerulean Warbler, Northern Aplomado Falcon, and Gunnison Sage-Grouse. They also found that lands owned by states and by non-governmental organizations performed better than private land, with 4.6 percent and 4.5 percent of endangered habitat lost, respectively, over the past three decades.

The study arrives at a time when federal lands are losing protections at an alarming rate. In 2017, for example, the Trump administration slashed Utah’s Bears Ears National Monument by 83 percent, leaving the excised acreage still in federal hands but open to mining, drilling, and other industry. In Alaska, the Department of the Interior says it’s finalizing a plan to begin selling off drilling rights in the Arctic National Wildlife Refuge, despite acknowledging that drilling there, coupled with climate change, could drive some bird species to extinction. And William Perry Pendley, the man assigned by the Trump administration to run the Bureau of Land Management—which oversees 245 million acres—has in the past lobbied for opening more public lands to industry, fought to weaken ESA protections, and written publicly, “The Founding Fathers intended all lands owned by the federal government to be sold.”

Much of the nation’s federally protected land lies in the West.

Much of the nation’s federally protected land lies in the West, which can pose a problem for vulnerable eastern birds such as the Florida Scrub-Jay. Increased development in Florida, along with a relative dearth of protected land, is putting the bird—which does not migrate and lives only in its namesake state—“in the crosshairs,” according to Evans.

Other federally endangered birds like the Red-cockaded Woodpecker and Golden-cheeked Warbler likewise inhabit ranges that consist mostly of private lands, Evans notes. “We know that there are many imperiled bird species that don't have the privilege of having the range of the federal lands,” he says. “So our results suggest that if we are equally interested in conserving bird species, certainly globally and also in North America, there's going to have to be some extra provisions or measures that are taken to protect habitat in private contexts.”

Some such programs have proven effective at conserving habitat on private lands. The U.S. Farm Bill, for instance, funds conservation programs and partnerships that have put significant amounts of new or improved bird habitat on agricultural lands across the country. And Audubon’s Conservation Ranching Initiative helps to promote healthy grassland habitat through sustainable, bird-friendly beef production. Still, when it comes to conserving habitat specifically for endangered wildlife, property rights and legal exemptions in the ESA make it harder to ensure protected species aren't losing ground, the study authors say.

Along with demonstrating the conservation value of federal lands, the findings also underscore the effectiveness of the ESA itself. While most of the endangered species featured in the study are protected by the Act, some were only part of the Red List of endangered species compiled by the International Union for Conservation of Nature. This is an important distinction because the Red List, designed to inform the public and drive conservation efforts, does not itself provide legal protection. Some Red List species became ESA-listed during the research period and lost significantly less habitat on federal lands after gaining ESA protection than before.

Despite the ESA’s effectiveness, the Trump administration has issued rules that significantly weaken it, including a measure that makes it easier for economic factors to influence decisions about which species gain protection. Environmental groups and several states are challenging those changes in court.

“The new ESA regulations issued by this administration make it harder to identify and protect habitat, including on public lands,” said Nada Culver, vice president of public lands and senior policy counsel at Audubon, in an email. “This study shows us that protection under the Act results in a real difference for species and their habitat.”

Although the study only focused on 24 species, for its authors, the findings point to larger ecosysteam concerns that further support the need for broad and continued habitat protections. “All of these animals are interconnected," Eichenwald says, "so what happens to one from habitat loss is bad for these other animals as well.”