Military Macaw. Photo: Genji Arakaki/Flickr Creative Commons

Earlier this month, two beleaguered birds, the Great Green Macaw and the Military Macaw, gained the unfortunate distinction of being added to the U.S. endangered species list (the roster of species whose protection is mandated by the Endangered Species Act). But neither bird is a U.S. native. Instead, these spectacular parrots hail from parts of Mexico and Central and South America, where their populations are plummeting, primarily from habitat loss and the exotic-pet trade. Wild populations of the Great Green Macaw, for example, have dropped by more than 50 percent over the past 10 years.

Since neither species resides in this country, U.S. laws can’t directly protect them from poachers and loggers. So what, exactly, does listing them under the Endangered Species Act do? Here’s some background on the ESA and how it can—and can't—help international species, including the two macaws.

Has the ESA always protected foreign species?

Yes. Since its inception, the act has stated that all species in danger of extinction be listed, regardless of their country of origin. In fact, concern over high-profile international animals—such as whales, which were facing wholesale slaughter in the 1900s, and leopards, whose furs had become a fashion mainstay in the ’40s—is what really drove the passage of the ESA in 1973, says Joe Roman, a conservation biologist at the University of Vermont and the author of Listed: Dispatches From America’s Endangered Species Act.

A 1966 precursor to the ESA didn’t include foreign species (or any invertebrates or plants). But a few years later, the passage of a second ESA predecessor prompted the U.S. Fish and Wildlife Service to put together a list of about 250 endangered foreign animals, including tigers, lemurs, Ostriches, and Galápagos Penguins. Those species were then grandfathered in when the ESA became law. Today the act protects about 654 foreign species in addition to more than 1,500 U.S. ones.

How many of these foreign species are birds?

In theory, the two federal agencies responsible for implementing the ESA—the USFWS and the National Oceanic and Atmospheric Administration—aren’t supposed to favor one type of animal over another. Still, larger animals dominate the list. There are 234 foreign bird species listed as threatened or endangered, and even more foreign mammals. By comparison, the act protects only nine foreign amphibians, four insects, three plants, and one snail.

One reason for this imbalance is that birds and mammals, along with reptiles, are generally far more likely to be sold on the black market, which the U.S. can influence. “If [a species is] at risk because of habitat loss or something else the U.S. doesn’t have direct control over, it sometimes isn’t worth going through the whole listing process,” Roman says. “I think they’re often making these decisions based on [whether] they’re going to have some leverage.”

So how does the act work outside of U.S. borders?

Though the U.S. government can't really control how other countries manage their natural resources, the Endangered Species Act does have some teeth internationally. First, it bans the import and sale of all endangered and threatened species in the United States (with exceptions for scientific or captive breeding purposes). “Listing foreign species is actually really important because the United States is such a significant market for the illegal trade in wildlife,” says Daniel Rohlf, a professor at Lewis & Clark Law School in Oregon who specializes in biodiversity issues. “Without [ESA] barriers in the U.S. market, a lot of species around the world would be in more trouble than they are now.”

On a more conceptual level, ESA listings can raise public awareness about species and put pressure on their home countries to take action to protect them. Listings can also provide impetus for research and funding partnerships that then benefit the species. Vanessa C. Kauffman, a USFWS spokesperson, points to the straight-horned markhor, a wild mountain goat in Pakistan, as an example. A key population of this species has gone from 200 individuals to more than 3,500 in the 30 years since it was listed, thanks in part to a local conservation program and funding from the United Nations and international wildlife groups.

Is this different from CITES?

The Convention on International Trade in Endangered Species of Wild Fauna and Flora, better known as CITES, bans the commercial trade of about 1,200 species and restricts it for an additional 21,000. CITES and the ESA are closely intertwined: The ESA is what allows the U.S. government to implement CITES, and enforce programs, incentives, and fines that benefit the species protected under CITES. That’s why many species, including Military and Great Green Macaws, appear on both lists.

An ESA listing does provide benefits beyond those offered by CITES, though—it can also list species that aren't primarily threatened by trade. Furthermore, the act bans sales across state lines, as well as some non-commercial imports. “If you live in, say, Colombia and move to the United States, you can’t bring your [Military or Great Green Macaw] with you" if it was obtained post-listing, says Sarah Uhlemann, international program director at the Center for Biological Diversity.

The ESA’s main advantage over CITES, however, is that the United States has a certain degree of control over a species’ fate, “regardless of what the world decides,” Uhlemann says. So even if, say, the member countries of CITES decide to delist the macaws, the ESA would continue to protect them.

What else can the ESA do to help foreign species?

Not much. The act used to permit the USFWS and NOAA to reject federal operations and investments in foreign countries, if those actions were found to “jeopardize the continued existence” of a listed species. But in 1986, the Reagan administration exempted those overseas activities from ESA compliance.

Not surprisingly, U.S. agencies have since taken advantage of the exclusion. In 2012, for example, the Export-Import Bank of the United States loaned out $4.8 billion for the development of two liquefied natural gas projects in Australia’s Great Barrier Reef, which is home to many endangered and threatened species, including dugongs and saltwater crocodiles. The Center for Biological Diversity and two other conservation groups are currently challenging that loan in court; they hope that a legal victory will resurrect the ESA’s foreign provision. Of course, the USFWS also has the power to bring it back, but hasn’t made any moves (publicly at least) since the Reagan years.

Correction: An ESA listing bans interstate sales, but it doesn't stop all petshop sales and all non-commercial imports as previously stated. If the animal was purchased before the listing it won't be affected by the import rules. Also, the wording in the final two sentences was altered to make it clear that USFWS can amend the foreign provision, but not the ESA itself.