Army Ants

Years ago, I joined Lee Harper for a World Wildlife Fund trip into the Brazilian Amazon. Lee had studied army ants in rainforest near Manaus, setting out to learn how big a forest patch needed to be in order to retain its army ants and the obligate antbirds, which need to follow army ants in order to survive. Lee developed a novel method of transporting ants into variously-sized forest fragments.

Army ants don't build permanent nests. Instead their colonies roam unceasingly through the forest, preying upon insects and other small animals in their path. But they do go through two phases, a nomadic phase lasting about 2 weeks, when their food needs are greater, and a stationary phase lasting about three weeks, when the colony protects the queen and her eggs in a bivouac formed of living ants. During the nomadic phase, the bivouac's location changes nightly. During the stationary phase, they still do some raiding, but return afterwards to the same bivouac.

Army ant column in Guyana (Photo by Narca)

When the ants bivouac, they form a living nest of the interlocking legs and mandibles of as many as a million ants, protecting the queen and her new brood at the center. This living nest is complete with chambers, bridges and corridors.

Lee would capture the queen and place her on crossed sticks inside a very large metal garbage can. Then he'd wait for the colony to bivouac around her. Once the ants had formed their living nest, he would place the lid on the garbage can and duct-tape it shut. Then he could place the entire colony on a backpack frame and carry it into a forest fragment. If the forest fragment was large enough (say, 100 hectares), the ants would stay. Otherwise they marched in a straight line out of the forest patch, setting out in a random direction across the denuded land in search of a forest big enough to support them.

Lee quickly learned to be sure that the lid of the garbage can was well-secured!

Guyana's Emerald Forest

With over 80% of its rainforest intact, Guyana holds splendid riches for travelers who wish to explore those towering forests. After first journeying there on a "fam" tour, I return as soon as possible for more in-depth scouting with Alan and our friends, Noel Snyder and Jim Shiflett.

With the Brazilian Shield, the ancient Guianan Shield forms the primeval geological heart of South America. There we find the iconic Neotropical birds––toucans, macaws, parrots, cotingas, antbirds, cocks-of-the-rock, hummingbirds.

Let's look at just one spot: Atta Rainforest Lodge, deep in the Iwokrama Forest. The Iwokrama's protected lowland tropical rainforest is renowned for its spectacular biodiversity. Jaguars roam the forest by-ways, and monkeys chitter overhead. Giant River Otters roll in the small stream channels, beneath the slender, leafy perches of brilliant Green-tailed Jacamars and Crimson Topaz hummingbirds.

Green-tailed Jacamar (Photo by Narca)

By day the four of us roam the forest trails with our local guides, Ron Allicock and Archer, both Macushi Indians, and both deeply attuned to every nuance of this wilderness. Huge Red-necked Woodpeckers (the cousin of our Ivory-bill) are abundant and conspicuous. We find one nest, and Noel stations himself nearby to photograph this spectacular woodpecker as it makes forays to and from the nest cavity.

Red-necked Woodpecker at nest in a termite-shrouded tree
(Photo by Noel Snyder)

Soon we become aware of antbird activity and of busy columns of army ants. Then we find the advancing front of this army, as well as a vantage point for watching the phenomenon. First a trickle of scouts reaches the new region, and every small animal in the vicinity begins to flee. Soon the main army arrives, and the leaf litter boils with literally tens of thousands of foraging ants.

Birds are quick to snap up an easy meal among the fleeing insects. Antbirds and Gray-winged Trumpeters patrol the lower regions; woodcreepers grab insects from a few feet higher up. Even insects that fly all the way into the canopy may find toucans or other birds hungry for a meal. I once watched a Barred Forest Falcon in Belize, as it perched a few feet off the ground, intent on finding a meal in the midst of the commotion.

Gray-winged Trumpeter (Photo by Alan Craig)

Standing (carefully!) at the advancing front of an army ant swarm is a memorable, remarkable experience of Rainforest––and an experience that Guyana regularly grants to visitors. I look forward to returning in November with our Naturalist Journeys group. (You're invited!)

Ron Allicock, our local Guyana guide

(Photo by Noel Snyder)

Guyana's Harpy Eagle Nest!

Ron Allicock, a very skilled Macushi guide from the deep Guyanan rainforest, emailed me that a Harpy Eagle nest near his village now holds one young chick. (Isn't it amazing how email now connects someone in a remote Amazonian thatched cottage to another person in an old adobe art gallery on the US western frontier?) That nest is cause for big excitement!

Harpy Eagle (Pen & ink by Narca)

Spectacular Harpy Eagles are among the world's most powerful, largest raptors. A female stands over 3 feet tall and has a wingspan of about 6.5 feet. Sloths comprised the bulk of their diet in one study, supplemented by the occasional monkey, coati, kinkajou, or opossum. Harpies are critically endangered over much of their vast range. Intensive efforts to monitor the species have turned up about 60 nesting locales, almost all within the Amazon Basin.

Chicks fledge in about 6 months, then spend another 6 to 10 months dependent on their parents, as they learn the skills they need to survive in the rainforest. That timing gives me hope that the Harpy Eagles under Ron's watchful gaze will still be in the area when our Naturalist Journeys group goes to Guyana next November 15-24. (We still have a spot or two on the trip if you're interested! Check out the itinerary at www.naturalistjourneys.com/jcalendar/jc_guyana10.htm.)