IN ONE OF Aesop’s fables, “The Rogue and the Oracle,” a man approaches the Oracle at Delphi. In his hand, which he keeps hidden under a cloak, he has a little bird. The plan is to ask the oracle whether the bird is dead or alive: if the answer is “dead,” he will simply produce the living creature; if “alive,” he’ll crush it. But an oracle is not an oracle by being easily tricked, and the reply is this: “Stranger, whether the thing that you hold in your hand be alive or dead is a matter that depends entirely on your will.”

I was reminded of that line while looking at artist and architect Maya Lin’s recent exhibition at New York’s Pace Gallery. There, from projectors attached to the ceiling of one of the gallery’s side rooms, ferries of sentence traveled across the wall, turning when they reached a corner as if hitting a bend or rapid. The words included historical accounts of the wolves that used to live in Manhattan, the oyster beds that once flourished around the Hudson, and a seven-foot sturgeon spotted in 1950 on the river’s New Jersey side by the writer Joseph Mitchell.

Lin is best known for designing the Vietnam Veterans Memorial in Washington DC, a competition she won in 1981 while still a student. The finished site, together with the precocious grit with which she met the obstacles to realizing it, turned her into a celebrity. Since then Lin has gone on to do other memorials, including the Civil Rights Memorial in Montgomery, Alabama, but for a long time she has said her last such project is in the works. Launched in 2011, the new memorial is ongoing, dispersed, collaborative, a kind of museum — that room at Pace with the running text is a part of it, though just one of many. There are satellite sculptures and multimedia installations planted throughout various cities, but the core of the project lives online, on an unusually cool website called What Is Missing? As for the “missing,” well, that would be animals and their habitats. The site honors extinct or endangered species, ecosystems lost or degraded, and, on a positive note, conservation efforts that have done some good.

In a departure from Lin’s previous offerings, the project is forthright about mission — a piece of “guerrilla artwork,” to use her own phrase. It’s an apt description, but don’t expect this project to behave like a political pamphlet. The information that populates the site is discreet, its clean restraint a catalyst for the viewer’s emotion; moreover, some of the power of the facts stems from what’s unusual and suggestive about their context. The very idea of a tribute to the extinct reminds us, by contrast, of what societies usually choose to commemorate: people as opposed to animals or places, the named rather than the countless anonymous, losses within recent memory. (Though a memorial like Lin’s might plausibly have begun with the Industrial Revolution, prehistoric megafauna figure in its scheme.)

While the concept does manage to avoid the challenges that go with remembering a human tragedy — mercifully, animals can’t dispute your design or stir up false controversy — other problems beckon. A memorial doesn’t work if visitors aren’t moved, and how do you move people with respect to beings that, all too often, they have never experienced firsthand? And since advocacy is intrinsic to the subject, how do you help fortify the will to do something? Part of Lin’s response to this pickle is to test the whole memorial genre formally: “I love rethinking what things are, changing assumptions,” she’s said in an interview, “so what if a monument, which we normally think of as being singular and static, can exist in many places simultaneously?” The digital world answers that call, and even enables viewers to interact with and add to the project over time.

But what of the site itself? As you enter to a concert of twittering and croaks, little dots move in a swarm across the screen, assume the forms of certain animals, and then take their allotted seats on a darkened map of the world. Placing the cursor over a dot reveals the name of an animal, place, or ecosystem; click on it, and a number of things might happen. An excerpt from Captain Cook’s journals may pop up, or a video begins, suddenly placing you in a mangrove swamp or before the enthralling dance show of a prairie chicken (he’s a must-see). As at the Pace show, brief sentences accompany the video entries — data about shrinking glaciers, bald eagles and DDT, commercial fishing laws unenforced, the disastrous toll of hunting and poaching for rare animals. With a video of pteropods, the text only has to explain what we’re looking at: the marine snail’s lack of shell is a new development, the result of ocean acidification. Visitors to the site are welcome to add their own memories, too. A resident of Spring, Texas, on the disappearance of fireflies from her town, writes: “It’s been twenty-five years, and I have not seen one since. I miss them.”

I won’t describe how the website functions in every detail — there are too many facets to it, and the point seems to be to discover them for yourself. Also, tech-impaired, I’m still working them out. Yet the sheer sensory pleasure of the site is worth noting. The quality doesn’t seem incidental: in a memorial to extinct animals, it won’t do to simply list names — the reduction of wildlife to text and statistics, to be filed away and forgotten, is part of the problem. A reconstructed memory would require that we picture the beast in question, read stories of actual encounters, hear the animal’s voice itself. All of this is included in What Is Missing? and among its auditory treasures are growling jaguars, the shrill yet somehow fetching cry of Indri lemurs, and “The Most Beautiful Sound of the Humpback Whale.” So-called “background” noises of forest and ocean are acknowledged as dynamic foregrounds; from what I can tell, there are no narrating human voices. The cumulative effect is soothing and makes it more likely that one will take time wandering from entry to entry, getting happily lost as though in a museum.

That a site so sadly themed is actually enjoyable speaks nothing against its seriousness. In fact, that element bolsters the project’s political stance, telling us what a memorial of this kind must do to be effective: make you want to stay. For a memorial to contain so much in the way of aesthetic seduction, seeking to lure us in and make us return and keep learning things, underscores a hard truth about extinction: on the whole, we are terrible at staying on the subject. When the barrier isn’t disregard for all that doesn’t obviously touch self-interest, it’s the demands placed on our attention by the usual plethora of other crises in the world. And then one suspects there is just something intrinsic to the topic that prevents us from thinking about it clearly. Extinction, after all, is mighty Death crowned, a more absolute death than death — hardly surprising, then, if it tends to be avoided, smoothed over, or if it plays tricks on people’s brains. Just as people will dream of the departed or catch themselves in anticipation of their presence, one sometimes hears the plight of threatened creatures referred to in a curiously resigned way, as though a species might just check out for a while and show up again another time.

To some extent, an inability to absorb the phenomenon is natural: we’re often talking about animals unseen by most people and scales of time and numbers so large as to challenge sympathy. Fresh opportunities for engagement, one hopes, will help rescue the cause from its abstract glare. A memorial like Lin’s is smart to emphasize geography, identifiable causes, and successes in conservation, while also showing us how the long-range view might serve as a source not of indifference, but of sadness and outrage. To imagine that, by our own hands and in such a short passage, so many ancient and hard-won chains of life could be severed!

In Aesop’s day, estimates put the world population at 100 million — in other words, about seventy times fewer than the present figure. Given the relative abundance of other life on earth at that time, it’s natural that the plight of the bird doesn’t seem symbolic or even really the point of the fable mentioned earlier, but rather more like an attractive literary device. Read through the lens of our modern day, though, it turns central. Now that we’ve come to know the oracle’s truth on a grander scale, how do we stop wasting time with the disingenuousness of the rogue?