Requiem for the Passenger pigeon - a sad centennial

Some years back ("never mind exactly how long ago," as Ishmael says), I had a chance to look in on Martha, the last passenger pigeon, in her eternal home at the Smithsonian. All I can say is that she looked lonely, as well she should have.  I still have a Kodak Instamatic snapshot, but it's hard to tell it's even a bird, so I won't inflict it on you here.
Her species went through the biggest massacre of wildlife in all history, ending exactly 100 years ago today with Martha's demise in the Cincinnati Zoo. The pigeon once lived in unaccountable numbers: John James Audubon reported a flock took three days to pass overhead. A hundred nests were once counted in a single tree.  Centuries of Native American and early European hunting made no dent in this multitude, but shotguns, nets, and other tricks of the 19th century did.  Mass hunting for sport, meat, and feathers, combined with the destruction of forested habitat, somehow reduced billions of birds to one.
There is not much doubt the pigeon was extinct, although; for the record, a Professor Philip Hadley reported glimpsing a passenger pigeon in 1929 in northern Michigan. There was a trickle of sightings all the way up at least until 1965.  There is not, however, any real hope, and ornithologists consider Martha's demise definitive. (A poignant footnote: the last confirmed Carolina parakeet, Incas, died in the same zoo three and a half years later.)
So we know to the day, almost to the minute, what happened to the most abundant bird ever to live.
Farewell, Martha. We're sorry. May we all learn your lesson.

Martha, as displayed in 1956