A pair of Bicolored Antbirds heralded the flock, flying out from the undergrowth to land next to the trail, give a couple of harsh call notes, and then dive back in.
I'm not sure I can really paint the picture of the antswarm. Different species worked the forest floor, mostly staying at the periphery and then darting into the area that the army ants must have been scouring. A Black-faced Antthrush ran atop the leaf litter while the Song Wrens would actually duck under to forage rapidly beneath the leaves. The antbirds moved much more methodically, stopping to preen or remaining in a secluded dark perch before dashing out after an espied disturbed insect. Our lifer Ocellated Antbird favored the latter approach, staying well hidden.
A Chestnut-backed allowed slightly better views.
Checker-throated Antwrens were common.
We wouldn't encounter White-flanked Antwren again until the last full day of the trip.
A Barred Woodcreeper was about triple the size of the antwrens.
And above the mid-story, interior forest flycatchers peered down looking to snap up insects attempting to completely bug-out. This odd little bird is a Ruddy-tailed Flycatcher.
While the Antpitta would remain hidden for this day at least, and there was no Ground-cuckoo miracle (though you're as likely to find that rarity on Pipeline as just about anywhere in the world), the hour or so we spent with this antswarm before it dissipated was one of the most rewarding experiences I've had in the natural world.