Passenger pigeon population had booms and busts

Humans made it hard for the birds to recover from hard times

UPS AND DOWNS  Passenger pigeons flocked in huge numbers in the 1800s, but new DNA analysis finds evidence of small populations in the birds’ deep history.

Patrick Coin (Illustration by Louis Agassiz Fuertes)/Flickr (CC by 2.0)

Passenger pigeons, so abundant during the early 19th century that skies darkened with passing flocks, may often have been nothing special in numbers during much of their last million years.