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On this day in 1914, a passenger pigeon named Martha was found dead in the bottom of her cage at the Cincinnati Zoological Gardens. She was 29 years old. She also was the last living member of Ectopistes migratorius, a species that was once perhaps the most prolific bird on the planet. Prior to the European colonization of North America, there was an estimated population of three to five billion passenger pigeons, amounting to 24 to 40 percent of the birds on the continent. Passenger pigeons’ habitat stretched from the Atlantic coast to the Rocky Mountains. The migratory birds traveled in enormous groups that literally darkened the sky for days, according to early explorers’ accounts.

The passenger pigeons needed large forests to feed, and when white settlers began clearing the forests for farming in the 1600s and 1700s, the species gradually turned to eating grain from their fields to survive. Farmers, in turn, shot and poisoned many of the pigeons. But the big blow to the passenger pigeon was the discovery that they tasted good when cooked. Because of their communal lifestyle, passenger pigeons were easy to catch, and starting in the early 1800s, hunters descended upon their gatherings and slaughtered scores of them at a time for sale in city markets, putting burning sulfur pots under trees to daze young birds and cause them to fall from their nests. By the 1850s, the passenger pigeon population was noticeably decreasing, but the pleas of naturalists to slow the killing fell upon deaf ears. One of the last sightings of a great gathering of passenger pigeons occurred in Petosky, Michigan in 1878. Hunters killed an estimated 50,000 birds a day over a five-month period. When the survivors fled and tried to establish a new roost, they were again tracked down and slaughtered, before they could produce any young. By the 1890s, state legislatures finally began to pass laws to protect the passenger pigeon, but by then, so few were left that the species could no longer sustain itself. Today, Martha, whose stuffed remains are part of the Smithsonian collection, is a reminder of how cruelly myopic humans can be. Let’s hope that in this century, she isn’t joined by the last mountain gorilla or white rhino.


And with that sobering warning, here are the science stories of the day.

To the bafflement of demographers, fewer teenagers are driving in the U.S.
 
Between 1978 and 2008, the number of teens with drivers licenses fell by a third, contrary to population trends. Maybe they’re all staying at home playing Grand Theft Auto.

“The Skeptical Environmentalist” author does U-Turn, says massive $100 billion global effort needed to fight climate change.
 
Deniers used to take comfort in the contrariness of Danish business professor and author of Bjorn Lomborg, who campaigned against the Kyoto Protocol and argued that a little warming was really not all that bad of a thing. But in a new book, he radically morphs.

Arctic Ice: Less than meets the eye, scientists warn. It may not retreat as much as last year, but what’s left underneath is not in such great shape.

Location determines social network influence, according to researchers. And no, you noob, they’re not talking about whether you access it from your living room or from Starbucks. They mean proximity to the core, in terms of relationships.

Raw milk will either make you healthier, or make you sick, depending on who you believe. Anti-pasteurization activists say that raw milk strengthens the stomach and immune system. Epidemiologists point out that cases of nasty E. coli infections and other disease outbreaks from raw milk contamination are rising.

What makes rocks wander in Death Valley? Hmmm, better call Mulder and Scully out of retirement again.