My Year of Darwin (3/1/2014): The Indefatigable Army

"A small dark-coloured ant sometimes migrates in countless numbers. One day, at Bahia, my attention was drawn by observing many spiders, cockroaches, and other insects, and some lizards, rushing in the greatest agitation across a bare piece of ground. A little way behind, every stalk and leaf was blackened by a small ant." Charles Darwin, Voyage of the Beagle

This must have been an army ant swarm and they are impressive. Darwin more eloquently states how animals are getting the hell out of the way of army ants. They would come through the BDFFP continuous forest site and this was a good and bad thing. When we knew they were coming, it was a good thing, they cleared camp of nuisance ants, spiders, scorpions, etc. When we didn't know they were coming, particularly at night, it was a bad thing. This only happened once that I observed. Fortunately, because of a snoring issue, I set up my hammock away from the primary sleeping area (you could say I was exiled). At night I heard a commotion and apparently army ants had come into camp and somebody stepped out of their hammock to be covered in army ants. Yea, yikes.

It's easy to know when they're coming. Not only are the small creatures getting the out of the way. There are birds that follow army ant swarms that pick off the animals running ahead. These birds are composed obligate ant birds - those that only forage at antswarms and search the forest for swarms. White-plumed Antbird (below) is the most commonly captured antbird in the Manaus area. There are also the opportunists that forage at ant swarms as they pass through their territories but abandon the swarm as the ants exit the boundaries of the territory. 

White-plumed Antbird