At the base of a craggy hill in the middle of Central Park, under one of those rocky overpasses you're not supposed to pass over after dark, a waterfall settles into a shallow stream. The stream smells. Like pond scum, mostly, but also, a little bit, like urine. And damp stone. And the various salty-sweet scents of city that have been liberated from concrete via the steam of summer. It's late in the day, and the heat hangs, and a siren wails in the distance, and we are somewhere near, best I can tell, 99th Street. So it takes me by surprise when Rodrigo Medellín plops onto a rock, rolls up his pant legs, and plunges into the water.
He's looking for bats. Actually, technically, we are all looking for bats. Medellín, a professor at the National Autonomous University of Mexico, is a bat biologist. A celebrated one, in fact. And he's leading a group of us -- researchers, park volunteers, students, curious hangers-on -- as part of the Central Park BioBlitz, a 24-hour-long effort to take a census of Central Park's wildlife. Some 500 sophomores from the Macaulay Honors College are participating in the census -- a project, co-sponsored by the Central Park Conservancy, that is not only meant to provide data about the Park's biodiversity (some 800 species, at last count), but also, as College dean Mary Pearl puts it, "to celebrate science as a way of knowing."
There's been only one other biodiversity survey of this scale in Central Park, and that one took place via an initial BioBlitz exactly ten years ago. In 2003, Medellín tells me, he and his team found "three big browns in the Ramble" and "the carcass of a red in the Great Lawn." He says this excitedly. For a biologist -- one who happens to hunt bats for a living -- three big browns and the carcass of a red are good finds. They offer good data.
For the bats of the 2013 BioBlitz, however, the story might be the lack of data Medellín has at his disposal. Part of the point of the BioBlitz is to see which new species might have come to the park (some of the groups are given Western-style "WANTED" signs for species that ecologists suspect might be new to the ecosystem), and which ones might have left or died away (wild rabbits, for example, haven't been spotted in the park since 2006). And this is where Medellín will play a crucial role in the survey. Bats have never been particularly plentiful in Central Park, but there is good reason to believe that they're significantly less plentiful in 2013 than they were ten years ago. And that's because the bat population on the East Coast has declined sharply since the last census. Sixty-five percent of the U.S. population of big brown bats -- the kind of bat you likely picture when you picture a bat -- has died in recent years. And the population of little brown bats has declined by a whopping 89 to 95 percent, meaning likely extinction for the species.
There are the typical explanations for all this (human encroachment on habitats) and the less typical (human encroachment via wind turbines, which create pressure differentials that burst the blood vessels in bats' lungs). But the declines have reached extinctionary proportions for another reason, too: a fungus that attaches to bats' bodies, particularly their wings and snouts. The result of this is an illness known as white nose syndrome -- one that kills bats by compromising, scientists believe, their ability to hibernate. Sleep deprivation, essentially, brought to a fatal extreme. The syndrome has led to the death of nearly 6 million bats, across all species, since 2007. And for little browns, in particular, for reasons that are currently not well understood, the syndrome proves especially deadly: For colonies of little browns, the mortality rate can be 100 percent.
Medellín, for all these reasons, is not expecting to encounter a little brown bat among our survey. Which isn't to say, however, that he's not really, really wanting to. "If we could find one," he says, "it would be a treasure." When you're an expert on something that's facing extinction, hope is an important part of your toolkit.
Medellín's first word, he tells me, wasn't "mama" or "dada"; it was "flamingo." Some of his earliest memories involve studying the animals of Africa. He auditioned for a TV quiz show in Mexico -- and became the first kid to make it onto the program. He got to choose the topic he'd be quizzed on, and the topic he chose was "mammals." He made it through six rounds. Though he didn't win, in the end, professors at the University of Mexico -- leading experts on bat biology -- happened to see his performance. They invited him to work with them at their lab. He was 11 at the time.
From there, it's been bats all the way down. Medellín has been the author or co-author of more than 50 scientific papers in international journals, as well as 15 books and book chapters on bat ecology and conservation. And his work is taking on a new significance today, as bats' story has shifted toward endangerment and extinction. In all that, Medellín finds himself navigating two different, but related roles: data-driven scientist and emotion-driven advocate. "You never know what's going to happen in the future," Medellín points out. "If we'd had a stronger effort 10 years ago on bats, we would have shown the effects of the white nose syndrome." We would have had a greater chance of understanding the illness that is proving catastrophic for so many bat species -- species that, with a diet consisting mostly of insects, play a crucial role in maintaining the ecological balances we humans have come to rely on.