Saving North America’s Tallest Bird
Whooping crane recovery is one of conservation's great successes, but suddenly there are new and frightening threats.
Blackburn called the report "bad science," and Judge Jack wouldn't allow it as evidence because she didn't consider it "reliable." At this point, it wasn't difficult to predict the final outcome. On March 10, 2013, three years to the day after the initial fi ling, Judge Jack found that the Texas Commission for Environmental Quality had violated the Endangered Species Act by failing to provide adequate freshwater inflow to whooping crane habitat. And she enjoined the commission from granting new water permits affecting the Guadalupe or San Antonio rivers "until the state of Texas provides reasonable assurances to the Court" that new permits would not result in harm to the cranes.
It wasn't as if the plaintiffs had asked for much--just decent freshwater inflows from the Hill Country to San Antonio and Aransas bays in times of drought, as mandated by the Endangered Species Act. That's something the Fish and Wildlife Service, not private citizens, should have demanded and required.
The ruling, says Blackburn, is "vindication of the sound science and the dedicated efforts of Tom Stehn."
"Together with colleagues far and wide, we were thrilled by the depth of the Judge's report and her decision," says George Archibald, co-founder of the International Crane Foundation who flew from China to Corpus Christie to be the first witness in the trial where he spent three hours talking about the importance of fresh water inflows to coastal wetlands and how it relates to the survival of whopping cranes. "It was a most comprehensive and, I believe, balanced report. We expected a win for the cranes would result in an appeal. It would not be surprising if this case goes to the Supreme Court to test the ESA against state rights over water."
That's not to say that the new survey protocol is unsound science. It's "new" only for whoopers, having been used successfully for other species. Whether or not it is good whooper management remains to be seen. Stehn is not enamored of it. "Whenever a population is small enough and not moving around much, you can find all the individuals if the cover is right," he says. "On a sunny day you can see a whooping crane two miles away; there's nothing for them to hide behind. A complete, intensive census where you try to count all the birds is better than spending half the time and estimating. It's just common sense. They claim they have to do it this way [partly] because the birds are moving around so much now. I don't buy that. The'08-'09 birds were moving around a lot because of food shortages, but if I flew enough, I could count them all."
Pena has problems with the new protocol as well. "It's very difficult to draw comparisons when you make a change like this," she says. "And it was bad timing. I think it's worth the effort to do it Tom's way. I don't see why you'd want to change at a time when everything is under contention."
Blackburn offers this: "The size of the [2011-2012] flock, even by the service's own estimation, [was] lower than during the prior year, and the scientific record from electronically monitored cranes in the flock suggests more cranes may have died than in the drought of 2008-2009, which was the highest mortality ever recorded. But we'll never know what really happened, because the service has abandoned the methodology of counting individual cranes each month, as was done for 29 years, and instead has resorted to distance sampling. . . . We don't really understand [sampling instead of counting] because Tom Stehn seemed to manage just fi ne with more cranes. Recent statements by the service would make you think that they were covered up in cranes down there, which even their estimates don't support."
The new survey protocol was first used on cranes in the winter of 2011-2012, yielding an estimate of 254 on and close to the refuge plus or minus 62. So maybe there were 192 birds or maybe 316. Was the population plummeting, soaring, or stable? The service couldn't say.
Wade Harrell, Stehn's replacement and a seasoned and highly respected scientist in his own right, is painfully aware of these deficiencies. "The variance [between high and low estimates] is more than we would have liked," he told Pena and me. "We're trying to work on ways to narrow it. I think the new method is moving us in a direction where we can get a more precise estimate of birds."
The 2012-2013 estimate, released five days after Pena and I left south Texas, doesn't inspire confidence. It's somewhere between 178 and 362 birds--probably around 257, says the service. But Harrell had told us something that goes a long way toward justifying his agency's position: "When you have new staff come on board, you need a way to be consistent so there's data you can compare from one year to the next. For the first time ever we have a written protocol I can hand other biologists so they can understand exactly how we fly surveys." That's an essential element. There are, alas, no more Tom Stehns.
"Tom did a complete census; he knew the birds for decades, had an incredible knowledge of what to expect," says the Gulf Coast Bird Observatory's Chavez-Ramirez. "New people can't do that. On the one hand, we need a standard technique, but the new protocol doesn't collect the additional information that Tom's census did--like potential mortalities. We need to find other ways to gather that information."