Army Ant Swarm

“There are few sights in the rain forest as awesome as the foraging columns of army ants”

~Tropical Nature, Forsyth and Miyata

The reason army ant swarms are sought by neotropical birders is that the foraging ants force any small animals in the leaf litter to flush and escape ahead of the advancing ants. This in turn attracts professional ant-followers that perch just above the swarm and reap the rewards of a fleeing feast. If the swarm happens to be near a trail, It provides an outstanding opportunity to see many birds that may be tough to see otherwise. As long as there is a source of food, birds will tolerate humans in close proximity.

I had birded Costa Rica last summer and not once did we encounter an army ant swarm. So it was a great surprise to encounter a swarm on my first full morning in Panama, just down Semaphore Hill from the Canopy Tower on the trail called Plantation Road.

With my guide Domi, we set off on Plantation Road just as two school buses rolled in with middle schoolers from a private school in Panama City. We spent some time searching for a great tinamou whose haunting call gave us the false impression that the bird was just off the trail. We could not locate the bird, a strange sort of jungle chicken, related to rheas and ostrich.

Now that tinamou is close!

A little further down the trail, I looked off to the left and I saw a great tinamou 15 feet away! Now that was easy. Now why was this elusive chicken-sized sulker tolerating two hominids with optics? The answer was to be found in the sounds of beetles, spiders, and other invertebrates rapidly trying to escape a column of an army ant swarm that was working the edge of the trail. A great tinamou is not a professional ant-following bird but if a swarm passes through it’s territory, it will take advantage. The tinamou was also joined by two white-whiskered puffbirds, cocoa and plain-brown woodcreeper, a pair of gray-headed tanagers, and spotted antbirds.

A male white-whiskered puffbird joining the feast at the army ant swarm.

At my feet, invertebrates were fleeing to seek safely on the path. They were soon followed by army ants that covered the leaf litter but only came as far as the edge of the trail.

What an amazing experience on my fist full day of birding in Panama. It goes to show that in birding, to find an army ant swarm you need to be in the right place at the right time but you also need a good dollop of luck.


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