One of the most exciting things a birdwatcher can come across in the neotropics is an army ant swarm. Many species of birds have evolved to follow these ant swarms as they move across the rainforest floor. As the front line of ants progresses, all the insects that they disturb fly up or try to hurry out of the way. This is exactly what the birds are waiting for and they pounce and feast on these unfortunate insects. You can often tell that you are nearing an ant swarm by the excited chirrups and cheeps that the birds who attend the ant column are making.
On one occasion in Guatemala, I was lucky to be able to position myself a short distance ahead of the ant swarm. As the ants moved towards me, the birds that were excitedly feeding and jumping around ignored me completely. I managed to get this close-up shot of a Northern Barred Woodcreeper (Dendrocolaptes sanctithomae), who was only a few feet away from me!