March 2013. It was a misty morning in Gamboa, along the Panama Canal. The sun had yet to rise, but I stumbled out of bed to the tune of Palm Tanagers and Clay-colored Thrushes. Red-legged Honeycreepers hopped around frenetically in a tangle of vines in the backyard, while a couple of White-necked Jacobins took turns drinking their breakfast from a hummingbird feeder hung outside the kitchen window. Water bottles and field guides packed, and binoculars and cameras in hand, we excitedly piled in the car and headed down the road.
I was on a spring break birding trip with a few college friends. Jack, whose house served as our base of operations for the endeavor, ate a quick breakfast while flipping through the Birds of Panama field guide. Ben fiddled with his iPhone, quizzing Brendan and Benjamin on tropical bird calls. Graham inspected an interesting moth that had spent the night with the porch light.
We had just under two weeks to put a solid dent in Panama’s potential birds, a list of about 1,000 species in an area smaller than South Carolina. This particular morning, we were heading out to explore the world-famous Pipeline Road, one of the most biodiverse birding spots on Earth. An old remnant of some World War II plans for a cross-country oil pipeline, Pipeline Road is a narrow stretch of road cutting into dense tropical rainforest in central Panama. Though only 18 kilometers long, it presents an incredible way for people to see frogs, mammals, insects, and almost half of all Panama’s birds: A staggering 400 species have been recorded along the route!
Just before sunrise, we pulled up to a series of ponds shrouded in mist. They were the Ammo Dump Ponds, a known birding spot that marks the beginning of Pipeline Road. Studded with waterfowl and wading birds, this stretch of water is a great place to start the morning’s list. A diminutive Ruddy-breasted Seedeater lived up to its name, while a Snail Kite floated gracefully over the opposite bank. Purple Gallinules and Wattled Jacanas poked around the lily pads, and a Rufescent Tiger-Heron attempted to blend in among the reeds. A capybara lazily moved out of the way of the car.
We moved on from the ponds into the forest, which got denser and darker the farther we drove on. This first stretch of road we birded by leaning over each other to stick our heads out the car windows, craning our necks to detect any unusual sight or sound. Of course, it being dawn in the rainforest meant that almost every sound was unfamiliar, and there were very few sightings. Jungles are notoriously difficult habitats to bird in, where birds and insects and frogs often call within just a few meters of you yet still somehow hide behind three or four layers of foliage. Usually, the best method of seeing any of the birds is to find a clearing in the forest, where you can stand and scan the perimeter for movement. If you walk quietly enough, you might sneak up on creatures hanging out right along the path. Brilliant butterflies, such as the blue morpho, often fly floppily right along paths, and puffbirds and flycatchers perch just above trails, waiting for clumsy insects (like morpho butterflies) to fly by.
Incredible birds on Pipeline Road
Our list of incredible birds (with equally incredible names) grew by the minute: Blue-chested Hummingbird, Collared Aracari, Speckled Mourner, Stripe-throated Hermit, Violaceous Trogon, Double-toothed Kite. A plaintive whistle from the right side of the trail gave away a Streak-chested Antpitta, an incredibly secretive bird. A rustle on the other side of the path ends up being an agouti, a forest-dwelling rodent that looks like a tiny capybara or a tall squirrel with its tail chopped off. Every other bird was a lifer for me, and it was sometimes difficult to keep up with all the sightings being called out (my friends are higher-caliber birders than I am and had definitely studied the calls more than I did). But as is the nature of rainforest birding, there were many lulls in activity. Solid green walls on all sides, pale gray clouds above, and mud below were often the only things we could see. The clouds decided to open for a bit, though the rain barely made our already-sweat-soaked clothes any wetter.
Around mid-morning, we turned a corner on the trail and came upon a line of soldiers marching by. These were not humans, of course, but ants: army ants. A couple of lines of ants had started streaming across the path, the intimidating soldiers forming a living tunnel through which the workers passed. With enormous jaws pointed skyward, the hundreds of tiny bodyguards were a sight to see. But this was only the beginning…
Army ants are not just one species of ant; rather, the name “army ant” is given to a couple hundred nomadic ant species that live in large colonies that form massive predatory “raids.” The species that we had stumbled on was likely Eciton burchellii, the most common New World army ants.
Unlike many species of ants that form large colonies, army ants do not construct a permanent nest; instead, they build a living palace of ants in order to protect the queen. Literally hundreds of thousands of ants link their little legs and jaws together to create this amazing, writhing structure. When it is time to move on, the ants spread out and migrate across the forest floor, creating little rivers of death and destruction for any critters that lay ahead. This in itself is an incredible biological spectacle, but the truly spectacular part comes when all the other symbiotic species come into play.
The ants themselves will eat just about anything that doesn’t move out of the way, but there are plenty of insects, lizards, and frogs that are able to escape the approaching phalanx. But in doing so, they are forced to give up on hiding among the leaf litter and hop up into the trees, and it is there that they meet their untimely demise by a slew of other predators. Many birds make their living off following army ant swarms and hunting prey items scared up from the ground, much as Cattle Egrets and bee-eaters utilize buffalo, rhinos, elephants, and giraffes by opportunistically snagging any insects the large mammals rustle up. In Central and South America, army ants are constantly being followed by numbers of antbirds, antwrens, antpittas, antthrushes, and ant-tanagers, many of which are obligate ant-followers. Many other birds take advantage of the activity as well. Why pass up an easy meal?
As we watched the army ants crossing the path, we realized that these small streams of ants were just the first scouts in what would be an enormous raiding party covering hundreds of square meters of the forest floor. We quickly learned to watch where we were stepping, as soldier army ants give quite a bite. But once we figured out where to stand to minimize getting attacked, we began to see a stunning variety of birds. Bicolored Antbirds were the most numerous ant-followers, but several Northern Barred-Woodcreepers and an assortment of flycatchers were flitting about the understory as well. A cute little White-whiskered Puffbird sat quietly below eye-level, while a couple of Pied Puffbirds sat right above us. The prize of most beautiful bird species in the group definitely went to the Ocellated Antbird, which wore bronze and jet-black spots and sported bright blue facial skin.
One bird that we all hoped would materialize was the Rufous-vented Ground-Cuckoo, a species that is as secretive as it is alluring. Rufous-vented Ground-Cuckoos are large, terrestrial cuckoos of the neotropics, sporting a peculiar crest and a handsome purplish back. They have also been known to follow army ants.
Near the middle of the swarm was a Great Tinamou, a generally shy bird that looks like a fat, awkwardly adorable, gray chicken. We were excited to get such a close look at one, as the whole family of tinamous is known for being really tough to approach. Yet this individual was so preoccupied eating terrified little bugs that he didn’t seem to care that he was meandering right into this group of humans. For about 30 minutes, we enjoyed the presence of this tinamou, whom we decided to name Mark. We were not just able to relax and appreciate the interesting species and behaviors, we were forced to: For quite a while, we were very much surrounded by a staggering number of ants, and none of us were too keen on getting more bites on our ankles.
The whole experience lasted about an hour, after which the ants passed the trail and moved on, their avian groupies close behind. If any of us felt a bit of disappointment for not seeing a ground-cuckoo, we found solace in the unbelievably close looks we had of Dot-winged and Checker-throated Antwrens, Cocoa Woodcreepers, and Broad-billed Motmots. As usual in the treasure-hunt that is birding, missing the elusive ground-cuckoo gave us a reason to return another day. Slowly, we moved on and continued enjoying all that Pipeline Road had to give (at least until lunchtime!).
In less than six hours, we had seen agoutis, sloths, morpho butterflies, giant helicopter damselflies, and rocket frogs, which are related to poison dart frogs but have neither the attractive colors nor the deadly toxins. We had also seen almost a hundred bird species, a number that felt impressive, yet only represented a quarter of the birds we could have seen. It was a day that left us itching for more birding, if not itching all those ant bites.
This article was first published in the May/June 2022 issue of BirdWatching magazine.
Learn more about Central American birds that follow ants