While walking forest trails in the tropics, we use all of our senses to search for birds. While a swarm of army ants is a top prize in a neotropical forest, the swarm can be difficult to detect. As we slowly paced down the trail at Los Cusingos on Part 1 of the Costa Rica Edges trip, we started to hear leaves shuffling and the short, excited calls of Bicolored Antbirds. As we rounded a corner, a wide ribbon of army ants became visible, rippling across the trail in an odd, jerky, almost "stop-action animation" flow... and the birds followed. For nearly half an hour, we stood still, watching Bicolored Antbirds, Tawny-winged Woodcreeper, Blue-crowned Manakin, White-throated Thrush, and Gray-headed Tanagers just a few meters away as they pursued insects flushed by the marauding ants (not the ants themselves, though!). The birds were totally unconcerned about our presence as they had lots of food to watch out for. This was our own little window into the foraging ecology of a flock of ant-following birds, and we soaked it in until the swarm and its birds faded away into the forest. What a spectacle! I'm shaking a little bit just thinking about the experience of watching this swarm.