The Dilemma of Delisting Species

The bald eagle is proving what a lot of jailbirds already know: it can be a lot easier getting in than getting out.

The national symbol was supposed to have been removed from the Endangered Species List by now, but its “delisting” has been placed on hold. There doesn’t seem to be much debate over the fact that the white-headed raptor with the ferocious expression has rebounded somewhat in the years since Congress banned killing it in 1940 — long before the Endangered Species Act was passed in 1973.

Outlawing the use of DDT which destroyed its eggs, and taking measures to protect its habitat helped the bald eagle rebound from its precarious level of fewer than 500 pairs in the contiguous states less than four decades ago. There are believed to be nearly 1,200 pairs today in the “Lower 48,” and outside my office window in Alaska they are more common than pigeons.

So what’s the problem here? Partly, a lack of good science.

Gauging When Enough Is Enough

Federal officials wanted to point to the eagle as a stirring example of the successful application of a popular law designed to protect critters that are dying out, largely because humans have messed up their environment. But now they say they want to think about it a bit more because if the eagle is removed from the list, how can they be sure its habitat will be protected?

Environmental groups largely oppose the delisting because they see no gain, and some threat, in any relaxation of the monitoring and protection that is required under the law for a listed species.But the chief dilemma in removing any creature from the protection of the act is deciding when enough is enough.

The Endangered Species Act “provided no criteria for deciding when a species should be listed, delisted or ‘downlisted’ from endangered to threatened,” reports a team of researchers in the current issue of American Scientist.

Addressing the broad issue of when any animal should be delisted — the scientists conclude that “no management agency has come up with a rigorous and objective definition” for when a species can be considered “recovered.”

Popularity Contest?

Leah Gerber, a wildlife ecologist at the National Center for Ecological Analysis and Synthesis at the University of California, Santa Barbara and lead author of the report, says current decisions on conservation management are inconsistent and too often based on the popularity of a specific species, not the level or evidence of the threat.

Whales and eagles get a lot of attention, and any attempt to remove them from the list is bound to be met with hostility. A toad that is holding up a popular construction project is likely to get a lot less support than the national bird.

“Every year, populations of plants, insects and even microbes reach the brink of extinction, virtually unnoticed,” write Gerber and Douglas P. DeMaster, director of the National Marine Mammal Laboratory in Seattle, and Simona Perry Roberts, a biologist with the National Marine Fisheries Service. “In the meantime, the threat of large-mammal extinctions arouses public passions, attention and, ultimately, money. It is here, at the intersection of sentimentality and scientific controversy, that conservation biologists typically face their greatest challenge.”

In other words, this is an immature science facing very mature questions in a politically-charged environment.

Gerber and her colleagues are not arguing for a relaxation of the standards, but she notes that unless the criteria for “delisting” is explicit and clear for each species, there is grave danger that decisions will be based more on politics and economics than science.

And whenever the evidence is compelling, animals and plants that have rebounded ought to be removed or the list will become “just a list that isn’t really doing anything,” she says.

But what is most essential, she says, is for scientists to come up with clear criteria that will allow policy makers to decide when success has been achieved. And that’s tough.

It’s different for each species, and it can take decades to collect the data needed for good judgment. In some cases, the data is very difficult to get, and in other cases the animal makes it a lot easier.

Missing Data

Take the case of whales. Commercial whaling so decimated whale stocks around the world that nearly all whales were listed as endangered and are now protected under international treaties. But not all whales are the same.

Each year, almost like clockwork, the Northern Pacific gray whale passes the shoreline of California on its way to it’s spawning grounds off Baja California, giving scientists the opportunity to monitor its numbers quite reliably. The grays have enjoyed a steady growth rate to a population of about 26,635 individuals. As a result, in 1994, the gray whale became the only large whale to be “delisted.”

But other whale species, including the humpback, are less predictable in their migratory habits, leaving scientists largely guessing at their numbers. And there are so few North Pacific right whales that no one is sure just how many there are, but it’s probably fewer than a hundred animals at best.

So what was good for the gray was not necessarily good enough for the right whale, which may be headed for extinction.

“We haven’t seen a calf in years,” Gerber notes, adding that the whales may be so few in number that they are having problems finding mates and thus may not be reproducing at a sustainable rate.

But, as she quickly adds, no one really knows that.

Getting answers to questions like that could take decades and buckets full of research money. And none of that will help until someone with a lot of clout decides that the Endangered Species Act may itself be endangered if scientists can’t come up with the facts.

Only then will we know if the bald eagle is, again, master of the skies.

Lee Dye’s column appears weekly on A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.