How does a region handle an invasive species that's inhabited an area so long many would consider it native? Worse, what happens if the species' very name stands for beauty and grace?

Those are but some of the questions New York Senator Tony Avella has decided to delay for another two years amid a proposal from the Department of Environmental Conservation to kill the state's remaining mute swan population (numbering around 2,000) by 2025, according to the New York Times.

Environmentalists consider swans, which came from Europe to the United States as a species of decoration on large estates in the 19th century, a "prohibitive invasive species" because they diminish wetlands, displace native birds, are aggressive towards humans, and disrupt local aviation, according to the Times.

Not everyone agrees with the seemingly contradictory policy of mass killing a non-native species in the name of conservationism.

"I was horrified to learn that our state wildlife agency would make such an extreme, unfounded proposal, and do not believe that the DEC has provided evidence to justify the elimination of these beautiful swans," Avella said.

Like Avella, others have questioned the state's evidence against mute swans, so named for their quiet nature. Times writer Hugh Raffles, whose piece was in the opinion section for his strong views against the culling, argued that mute swans kill just half of one percent of New York's 400,000 waterfowl population, the native species to whom they are accused of displacing.

"And if, as the state claims but has difficulty demonstrating, mute swans really displace New York's native birds, there should be a debate about the criteria used to value one species over another," Raffles wrote.

One piece of criteria would seem to be beauty. After all, few debated last year's python hunt in Florida, where snake catchers were encouraged to trap and kill as many as the invasive species as they could. Distinguishing that hunt over this one, of course, was the rare prospect that every python would be caught and killed (and few were). Swans are in the open and more defenseless.

What if they weren't beautiful, and only invasive? Would Raffles make the same case?

Such an example occurs in T.C. Boyle's "When the Killing's Done." I only read the first 50 pages or so (because I'm not a huge fan of Boyle) but the basic plot centers around a Californian island once populated by a wide range of native birds but since infested with rats for centuries. An environmentalist proposes a plan to the community in which the rats would be mass poisoned in order to return the land back to its native species, but a pesky resident thwarts her every move using a similar argument to the one made by Raffles.

There is also a real-life "Rat Island" off the coast of Alaska, re-named Hawadax Island after environmentalists employed rodenticide around five years ago.