Who Can Identify the World's Rarest Butterfly- page 1 | Science | Smithsonian
The St. Francis Satyrs now number around 1,000 and are found in an area of less than 20 acres. (Melissa McGaw)

Who Can Identify the World's Rarest Butterfly

Two scientists are in a grim contest to document some of the animal kingdom's most endangered species

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Nick Haddad is a tall, quick-to-smile Minnesotan. But lest the easy grin fool you, he is also a man who likes to win. He wins in Scrabble. He tries to win in basketball. And he thinks he has won in the grim contest waged among biologists over which is the rarest butterfly in the world.

Haddad spends hundreds of hours a year studying the St. Francis Satyr, a small brown butterfly the size and weight of a folded postage stamp. The St. Francis Satyr lives at Fort Bragg, a military base near Fayetteville, North Carolina, and nowhere else. The St. Francis Satyr was once common but is now on the brink of extinction.

One part of the story of the St. Francis Satyr begins with beavers. If you’ve ever wondered just how whimsical evolution can be, consider beavers. They are the answer to that question and the punchline. They are giant rodents with ping-pong paddle tails. They live in houses they build of sticks. They dam rivers to make ponds and have teeth that will grow through their heads if not constantly worn down through use. Unfortunately, much of what makes beavers interesting also puts them at odds with humans. They impede the flow of rivers. They cut down trees. And they have thick, dense fur, perfect for a cape or coat. Consequently, the North American beaver, an animal that once may have numbered close to 90 million, is now rare in many regions and extinct in others. In much of the southeastern United States, including North Carolina, the beaver was gone by the turn of the last century.

The beaver’s story matters to butterflies because when beavers disappear, so do dams. Dams lead to ponds that eventually lead to meadows that sprout sweet young sedges, into which the St. Francis Satyr’s larvae sink their mouthparts one bite at a time.

When the beaver became rare, it appears the St. Francis Satyr did, too. Satyrs now number around 1,000 and are found in an area of less than 20 acres. The butterfly was discovered in 1983 by a collector named Thomas Kral. He named it in honor of St. Francis, the man who spoke to and, more importantly, listened to animals. Kral was convicted of conspiracy to violate the wildlife laws of the United States (though not the St. Francis Satyr, which was not yet listed as endangered or even known to exist when he collected 50 individuals). The Satyr persists both because of and in spite of the man who named it. It also persists because of war, or preparations for it.

In the United States, many plant and animal species, including the St. Francis Satyr, have benefited from military bases, where they tend to be relatively well protected from habitat loss. Despite the sounds of guns and bombs, the species are preserved. But the case of the St. Francis Satyr is a special one. The St. Francis Satyr may have survived because of bombs. At Fort Bragg, weapons—from big bombs to small bullets—are used nearly every day in soldiers’ training. The explosions start fires that burn the forests and allow sedges to grow on meadows, and with them, here and there, a few butterflies. Once the entire southeastern United States, from Florida to Raleigh, burned every few years naturally. Now Fort Bragg is one of the few places where the wilderness and its necessary flames remain.

So far bombs and the slow recovery of beavers, which are multiplying in the absence of hunting on the base, have saved the St. Francis Satyr at Fort Bragg, but just barely. Without more bombing (or other forms of burning) and beavers, meadows would grow over, bombed areas would grow back and the butterfly would have nowhere to go. Fortunately, this butterfly has advocates. St. Francis spoke on behalf of all animals. Nick Haddad speaks on behalf of just one, the St. Francis Satyr. He speaks on its behalf all the time, and when he does he tends to remind his audience that he is studying “the rarest butterfly in the world,” a statement that received little argument in the Southeast until Allison Leidner came to town and Haddad got competitive.

Allison Leidner is an unlikely character in the story of rare butterflies. Now a fellow at NASA in Washington, D.C., Leidner is a New Yorker with a fondness for city life who wanted to save species, to lift them up from the brink the way you might pick up a wounded bird. She came to North Carolina to study with Nick Haddad, and that was when the trouble started.

Not long after Leidner arrived in North Carolina, she heard about another rare butterfly, rumored to live on just a few islands of the Outer Banks. Allison decided to look for it and found it: it was lovely and rare, very rare. It did not yet have a scientific name. It still doesn’t. It is called, simply, “Atrytonopsis new species 1” or, as she dubbed it, the Crystal Skipper, an unnoted gem skipping among the dunes.

Anyone could see a Crystal Skipper if they wanted to. Many rare species live in hard-to-reach places, such as bombing ranges, but not the Crystal Skipper. It can be found in backyards on the islands. The tiny larvae of the Crystal Skipper crawl along grass leaves waiting to metamorphose, or on sand dunes or in a patch of grass behind the Food Lion. But wherever they are, the caterpillars often represent the entirety of their species. Most of the year no adults are flying through the air. No eggs wait to open. These larvae are it, the sum living total of what Leidner now thinks may be the rarest butterfly species in the world—or if not the rarest, the most precarious, perched as it is on the dunes between the rising sea and the encroaching city.

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