In this March 13, 2018 file photo, pigeons sit on a fence at Hancock Shaker Village, in Pittsfield, Mass. MassWildlife is asking taxpayers to check a box on their 2019 state tax returns to help clean up pigeon droppings by saving peregrine falcons, a threatened species that preys on pigeons. (Ben Garver/The Berkshire Eagle via AP, File)

Along with all the usual declarations and deductions, Massachusetts residents have been asked to keep something else in mind this tax season: pigeon droppings.

In an unusual and at times stomach-turning appeal, the state agency MassWildlife proposed that one way to fight back against the sticky messes befouling cars and damaging bridges is for taxpayers to check a box on their tax forms to support the state's endangered species program.

How so? Peregrine falcons are among the program's beneficiaries, and they prey on pigeons.

"Hate pigeon poop? Save peregrine falcons," begins the message on the agency's website and in a recent newsletter. It goes on to picture a typical motorist driving home from work over one of the state's major bridges.

"You're thinking about dinner as you wait in traffic when—PLOP!—something white and black falls onto your windshield," the post continues.

Next comes a scientific breakdown of the bird droppings that includes an explanation—for inquiring minds that need to know—of the precise difference between the dark and white portions.

And then, lest the reader believe it's all no more than a yucky nuisance, this warning: "This paste-like substance is so acidic and corrosive, that it can damage your car's paint job. And you guessed it, groups of birds all going to the bathroom in the same place can make man-made structures like bridges deteriorate faster."

Enter the peregrine falcon, a magnificent predator that can attain speeds of 240 mph (385 kmh) in high-elevation dives, no match for the slower and less agile pigeon, which just so happens to be one of the peregrine's favorite feasts.

Peregrine falcons disappeared from Massachusetts in the mid-1950s and soon after the entire eastern U.S., their demise largely blamed on the pesticide DDT, according to the state's Natural Heritage and Endangered Species Program.

After the chemical was banned, efforts picked up to reintroduce the raptor, sometimes confused with more common varieties of hawk.

In this June 2, 2015 file photo, Merri, one of the adult peregrine falcons living atop UMass Lowell's Fox Hall, lands on the edge of the roof after MassWildlife personnel returned her chicks after tagging them in Lowell, Mass. MassWildlife is asking taxpayers to check a box on their 2019 state tax returns to help clean up pigeon droppings by saving peregrine falcons, a threatened species that preys on pigeons. (Ryan Hutton/The Eagle-Tribune via AP, File)

To the surprise of some ornithologists, many of the newcomers eschewed their former rural habitats and became city dwellers. Instead of on cliffs, they began nesting on tall building ledges and bridges in urban areas where food sources—pigeons, especially—were more plentiful.

To help the falcons along, state officials and volunteers placed nesting boxes in strategic locations such as the Custom House Tower in Boston, the 28-story W.E.B. Du Bois Library at the University of Massachusetts-Amherst and the heavily traveled Tobin Bridge spanning the Mystic River.

"Falcon cams" were even installed to offer a continuous livestream of peregrine comings and goings.

The restoration effort is partially funded by voluntarily donations from taxpayers, who can choose to contribute to "endangered wildlife conservation" on their state returns. The money supports more than 400 threatened or endangered plants and animals, from bog turtles to timber rattlesnakes, but the peregrine falcon is easily among the most "charismatic," said David Paulson, senior endangered species biologist for MassWildlife.

Contributions to the fund have been increasing but remain well below levels needed, according to state officials and wildlife experts. About 23,000 taxpayers gave $312,000 through the tax check-off in 2017, the last full year for which figures were available, compared with the $178,000 provided by approximately 18,000 taxpayers in 2013.

It's not just bird lovers and conservationists embracing the slow but steady revival of the peregrine falcons.

State transportation engineers have noticed a reduction in the pigeon population on bridges with nesting falcons, officials said. Fewer pigeons means less waste building up on bridge surfaces, rusting the steel and increasing the costs for maintenance and bridge replacement.

"It's almost like a symbiotic relationship," Paulson said. "The structure provides the habitat, and the falcons kind of provide the pest management, for lack of a better term."

Officials hope drivers when completing their tax forms will also see the peregrine as a feathered friend that can make an unwanted splattering a bit less likely.

The falcons "are never going to eliminate (pigeons), but they can help to manage them," Paulson said.

Explore further Extremely fast dives help peregrine falcons maneuver to catch agile prey

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