Conservationists are trying to protect herons in New York by rebuilding a habitat for them on Prall's Island. (Ryan F. Mandelbaum)

Just 50 feet across a tidal strait from Staten Island sits a grassy, mile-long stretch of land. When I visited on a cloudy day last spring, I couldn’t see the bottom of the brown stream that flowed beneath a railroad bridge toward the strait. The black mud beside the stream was speckled with broken green glass and smelled of sulfur (and is still caked on my loafers). Nearby sat oil tanks, a factory with 100-foot smokestacks, and a dump lined with tugboat corpses.

There's no sugarcoating it: The landscape surrounding Prall’s Island is dumpy. But it was once a regular stopover for some pretty glamorous birds: the slender, four-foot-tall great blue heron and the all-white great egret. (Note, for the angry birdwatchers: The egret is technically also a heron.) The birds abandoned the island in favor of greener pastures, and New York environmental officials and activists has been working to lure them back ever since, as part of a broader restoration plan for New York Harbor.

“If the birds can make it here, they can make it anywhere,” says Rob Pirani, director of the New York-New Jersey Harbor and Estuary Program, which works to protect New York Harbor natural resources.

Hunters killed New York City’s herons for their feathers in the 1800s, and the birds were all but gone by the early 1900s. But the Migratory Bird Treaty — signed 100 years ago this year — set the stage for a recovery. It banned killing, buying or owning more than 800 species of birds, as well as their eggs, feathers and nests.

Herons were on the protected list and eventually returned to New York, reappearing around the harbor in the 1970s. But Prall's couldn't catch a break. In 1990, an Exxon pipeline burst, leaking oil into the waters surrounding the island. In 2007, the nonnative (and tree-killing) Asian long-horned beetle invaded the area, prompting the U.S. Department of Agriculture to order the city to strip Prall’s of all its trees and bushes. In 2012, storm surge from Hurricane Sandy washed over and destroyed the newly restored trees and shrubs again.

“We've been thwarted many times” on Prall’s Island, says Jennifer Greenfeld, assistant commissioner for forestry, horticulture and natural resources at the city parks department.

No one is sure exactly why the herons left Prall’s, but clearing the island of its trees could have stripped the big birds of the strong, woody nesting habitat they prefer by allowing a carpet of flimsy vines to take over. Raccoons have invaded the island as well, and could easily feast on heron eggs.

Herons are still common elsewhere in New York Harbor, and are one of New York’s charismatic species, according to Susan Elbin, director of conservation and science at New York City Audubon Society. That means they’re widely recognized and appreciated by the public. They’re awesome. While filming my video, I got so excited over spotting a heron that I mindlessly scrambled up a tree to get the shot, ultimately contracting a five-week case of poison ivy. “People don’t need to know a lot about ecology and conservation to ‘get’ a great egret,” Elbin says.

Restoring Prall’s Island will probably take years. Parks and Recreation Department folks such as Heather Liljengren gather native plant seeds from around the city, which they plan to replant on Prall’s in the next five years. The department also plans to introduce insects that eat invasive vines (but hopefully leave native foliage alone). Once the native plants are well established, the Audubon Society will try to lure the birds back by playing recorded bird calls and placing “snowmingos,” lawn flamingos painted white, onto the island to fool the birds into thinking Prall’s is a good place to roost. Similar ruses have lured back egrets in the past, according to Elbin.

This year, Audubon Society folks spotted the nest of another wading bird — the glossy ibis — on Prall’s. Maybe one day soon, the herons and egrets will join them.

Mandelbaum is serious about science, pizza, Guy Fieri and not much else. He enjoys writing about the environment, physics and the macabre. 

Read More:

A sloth risks its life every time it poops. Watch the harrowing act for yourself.

Everything you need to know about the new planet Proxima b (in gifs)

New Yorkers don’t know their rats well enough. One ‘rodentologist’ wants to change that.

Professor Jim Gates talks physics and whether we’re all living in the Matrix