The bird that blocked the sun

Two hundred years ago, passenger pigeons were the most numerous birds in North America, possibly the world. Large flocks Highly social, they often gathered in incomprehensibly helped passenger enormous flocks—massive clouds pigeons survive of birds that could literally block Passenger pigeons felt out the sky for hours or even most comfortable in large days at a time. Around 1860, a groups. With so many flight of passenger pigeons near eyes on the lookout, Toronto filled the sky for 14 flocks could easily find hours straight and held perhaps food. And large flocks 3.5 billion birds! also provided safety—no

Blue: distribution predator could make a Red: principal nesting range dent in such a huge Passenger pigeons lived throughout the eastern half population. Well, no of North America. Flocks would sometimes venture predator except one… beyond this range, if there was enough food. “The air was literally filled with pigeons; the light of noon-day was obscured Passenger pigeons roosted and as by an eclipse... nested in a wide variety of trees, The pigeons were still from hardwoods to conifers, from spindly willows to sturdy old oaks. passing in undiminished The enormous flocks filled every numbers, and continued available space in the trees. The to do so for three days weight of thousands of roosting birds caused even thick branches in succession.” to sag and often break. Witnesses ―John James Audubon, compared pigeons to a tornado naturalist, ornithologist, and painter for the damage they could do to a stand of trees.

A flock contained three Though each passenger pigeon visually distinct types of weighed only 9 to 12 ounces, the passenger pigeons: weight of thousands of birds could (L-R) juveniles, pull down an entire tree. males and females.

Today, gray bats also live in huge colonies, sleeping and hibernating in caves. Human activity has disturbed many caves, breaking up colonies and threatening the bats’ survival. Conservationists are trying to save the bat by protecting its home.

Map: Kaisa Ryding / courtesy UMMNH / CC-BY-NC-SA-ND Image (center): Louis Agassiz Fuertes / New York State Museum / PD-US Image (right): Louis Agassiz Fuertes / PD-US Photo (bottom): courtesy amareta kelly / via Flickr.com / CC BY