Sunday 30 March 2014

Panama - birding with an expert guide - Part 3




I like to prepare for upcoming bird trips by studying the species I'm likely to find and by reading as much as possible about the natural and human history of the places I am going to visit. However, lately I have begun to suffer from procrastination and a kind of attention deficit where I start to study and research and then about 5 minutes later, go watch TV, or have a nap, or sweep the carport. The biochemical brain circuit that would allow me to concentrate upon my desired subject seems defective, unable to stand much strain, liable to give out after a short session of effort. I blame this on my former occupation, thirty years of teaching English in public schools.  All the after-school, before-school and during-school marking of students' written work took a toll, according to my theory. Some vital factor wore out in my brain.

This is self-justification for my failure to adequately prepare for Panama. I learned a handful of birds, some tanagers, a few raptors, particularly the hawk-eagles, a few of the more conspicuous looking hummingbirds like the White-necked Jacobin and the Black-throated Mango, the icterids, mostly the pretty birds, but there were whole families I failed to study even in the most superficial way. The result was ... well, that's the story I am about to tell you.
On our third day in Panama Carlos took us to the beginning of Pipeline Road. The Americans cut this road partway through the isthmus during World War Two to service a pipeline that was never used. The road has become "one of the best places to see tropical forest birds in the Americas, with a species list exceeding 400" (A Bird-Finding Guide to Panama by George R. Angehr, Dodge Engleman, and Lorna Engleman, 2008). Once paved, now it's a rough track through primary and secondary forest. It crosses several streams and one way birders have seen allusive species is to use these streams as access,  wading along them deep into the forest as my friend Mike Force did with shipmates back in the 1990s during a hurried in-port. He tells of encountering a hostile troop of Red-mantled Howlers that roared and threw sticks and other objects at the birders. For a naturalist, such an interspecies interaction would be a high point, something exciting to remember.

Carlos had just directed our attention to some Snail Kites circling with Black and Turkey vultures when his cell phone rang. Another Canopy tour guide and his clients had spotted an army ant swarm at km 2.5 and attending it were two very hard-to-see birds indeed.

"Quick, quick! Everyone into the truck. Army ants and ground-cuckoos at km 2.5!"

Ground what? Ground-cuckoos? OK, here's the first time my lack of preparation kicked in. Ground-cuckoo sounded like an interesting bird, and we all knew at least in theory that very large mixed flocks of birds often attend army ant swarms, but I didn't know that the sighting justified Carlos's obvious excitement. The man is wonderfully enthusiastic, but wasn't he overdoing it?

Fig. 1 Rufous-vented Ground-Cuckoo. Photo by C Siddle


Here's what I didn't know: the genus Neomorphus has four species: Rufous-vented Ground-Cuckoo, Banded G-C, Rufous-winged G-C, and Red-billed G-C, and you would be hard pressed to find a New World bird genus less known than this one. All of them are found in huge tracts of South America jungle. The Rufous-vented is the only species also found in Central America north to Nicaragua. All of them survive only in very large areas of forest, and all of them appear to be naturally scarce. When Lake Gatun was flooded for the operation of the Panama Canal, a very large forested hilltop became Barro Colorado Island, and a forest reserve and research station for scientists from around the world, the Rufous-vented Ground-Cuckoo was one of the earliest bird species to leave the island, that's how much the bird needs isolation from disturbance and development.

Aside from being long tailed, large billed ground birds about the size of Greater Roadrunners (which are also members of the cuckoo family), almost everything remains to be discovered about ground-cuckoos. Nests remain unknown for the Banded and the Rufous-winged ground-cuckoos, and all that's known about the breeding of the Red-billed Ground-Cuckoo is that the nestling had buffy hair-like down attached to tips of its growing contour feathers on its head and that its bill is black. Because it occurs in Central America as well as South America, the Rufous-vented Ground-Cuckoo is the best known of this mysterious bunch but that's not saying much. It was only within the past 40 years that this species was discovered to have a nest at all, as opposed to being a nest parasite as some expected it to be.

So there we were newly arrived in a cloud of dust at km 2.5 of the Pipeline Road watching an adult Rufous-vented Ground-Cuckoo trotting around the edges of the forest through which army ants were swarming, picking up large insects and feeding them to its one offspring, a slightly smaller, darker billed version of the adult. Since I hadn't prepared properly for this trip, I failed to appreciate just how special this sighting was, even with Carlos and Michael, the other guide, telling us how lucky we were. Imagine my excitement had I actually known at the time that I was looking at birds, rare to begin with, behaving - feeding a juvenile - as very few people had ever seen them behave before.

Ground-cuckoo behavior around an ant swarm is well described in Volume 5 of The Handbook of The Birds of the World:

In the interior of forests of tropical America, the ground-cuckoos follow swarms of army ants, using the ants as beaters to flush insects. The cuckoo appears to wait until an ant swarm enters its territory, whereupon it follows the swarm as it passes through. as the ants move along the forest floor and insects scatter in their advance, the cuckoo waits on the ground or perches on low horizontal branches near the ground. On the ground, it then runs at the edge of the swarm, snaps up an insect or other forest-floor arthropod, and runs away in active bonding movements, changing directions, or it spins away; only occasionally does it flap, to get over a vine or to gain an elevated perch, but extended flight is uncommon. These cuckoos feed separately, usually with only one at an ant swarm...They are the largest birds in the forest which attend these army-ant swarms, where they appear regularly along with numerous other kinds of birds" (pp 527-8).

Being unprepared didn't devalue the experience of seeing the ground-cuckoo for me; however, being unprepared did change the nature of the sighting. I didn't realize the special qualities of the experience until after it had happened, until after I had been told how lucky I was and until after I had done some research that revealed to me just how fortunate I had been.

The army ants scurried randomly over the forest floor and we had to watch closely where we stood for fear of being attacked. "If you do get them on you, take off your pants immediately!" advised Carlos, though he neglected to finish his instructions, his attention caught by birds moving through the understory around the ants.



"Plain-brown Woodcreeper!" he shouted, but the woodcreeper I focused on wore fine black bars on his underparts. When I mentioned this to Carlos he glanced at my bird and said, "Northern Barred Woodcreeper too!" Eventually we added a Cocoa Woodcreeper to our list of the mixed species attending the ants. I had especially wanted to see woodcreepers, and three species in one flock exceeded my expectations.

Bicolored Antbirds of both sexes were common. Right in front of me a Spotted Antbird grew agitated for some reasons, flared its tail, raised its crest and revealed a pale area on the centre of its back. What's that about, I wondered. Nearby were three larger, much calmer appearing birds standing still on the leaf litter. These were Ocellated Antbirds, much larger than the Bicolored Antbird, Spotted Antbird and Dot-winged Antwrens, with pretty blue elongated spectacles and handsome black back feathers scalloped with fine buff edgings.

While the ants swarm over the ground, the birder is busy, really busy. He might be watching a bird through his binculars, letting them hang to take notes, making sure he has written, say, Bicolored AntBIRD and not AntWREN nor AntTHRUSH, lifting his camera to take pictures of any bird tame enough to stand still for a moment, checking the resulting images in the viewer of his camera, making sure he's standing clear of the ants, lifting binoculars again to peer into the shadows and between the branches for more birds, trying to untangle the binocular strap which has twisted around the camera strap, all the while craning his neck and his back at torturous angles to try to see around leaves and other objects that obscure his view, and avoiding bumping into other birders who are also attempting to do two or three things at once.

Fig. 2 A Spotted Antbird. Photo by C Siddle


On a sapling above me a Northern Barred Woodcreeper paused in its hitch upwards to flick its left wing partially open. This movement scared the ants scurrying down the stem over to the right side of the bark. Then it flipped open its right wing to send the ants back to the left side. It swiftly picked something - a little bug, an ant? - off the stem. Was it in effect herding the ants or had I just seen a couple of random wing twitches? Was this a hunting technique or was the bird just twitchy? Here was something else to make note of and search for in the reference books. (But that's for some other post.)

We ended our visit to Pipeline with sightings of White-shouldered Tanagers, a Scarlet-rumped Cacique, and a Slaty-tailed Trogon, among other birds.

In the mid afternoon we visited the former zoo at Summit Hill, now an animal rehab centre. Three caring volunteers brought out their young animal charges, a Tamandua looking very clean and smart in his brown and soft gray pelage, as if he were wearing brown bib overalls, a Geoffroy's Brown spider monkey wearing his Pampers, and a sleek dark brown Kinkajou, an arboreal relative of the Raccoon.
While we listened to the rehabilitators' stories of the difficulties of caring for wild animals in Panama which has no history of animal rehabilitation, and until recently, little history of conservation, we were cautioned not to reach out to the animals. With so much cuteness right in front of us, it was hard for some of us to resist, especially when the animals observed no such ban on touching and reached out various furry arms, legs, and noses to us.



After some of us cleaned out our wallets in donating to the animal's expenses, we moved next to a palm , the bottom edge of its canopy drooping a little. Here Carlos showed us four Common Tent-making Bats, small dark bats with thin pale stripes on their snouts. In order to make themselves a suitable roosting place the bats chew at specific points on the undersides of palm fronds. The fronds droop, the bat has a temporary home in the shade. Researchers theorize that tent-making allows small bats to save energy. Instead of flying long distances to the plants they are feeding on which are scattered through the forest, the tent-makers can spend the day hidden near their food source.

Summit Hill has a captive Harpy Eagle, possibly the most magnificent bird of prey in the world, certainly one of the world's rarest raptors. Like ground-cuckoos, the Harpy Eagle needs huge areas of undisturbed forest in which to hunt sloths and monkeys. With resource exploration and extraction, such isolation from human development grows ever more rare these days. One of the causes of Harpy Eagle decline is shooting. Such a huge bird offers a target that many people find hard to resist. Fortunately through the efforts of several organizations such as the Peregrine Fund, people throughout the Harpy's range are being educated about the value of this wonderful bird.

The Harpy Eagle at the Summit enclosure has a large flight cage but today the bird, a captive-bred female originally hatched in Florida, was perched next to the viewing platform. Unlike most hawks and eagles the Harpy has facial disks, rather like those of an owl, which aid in pinpointing sounds of potential prey. The Harpy Eagle hunts from within the canopy; it is not a bird that soars high over the forest like a Red-tailed Hawk would soar over forest edges back home.

Fig. 3- Captive Harpy Eagle at Summit Hill. Photo by C Siddle


We toured the grounds and added a pair of Masked Tityras, Lesser Kiskadee, and Yellow-headed Caracara to our lists before being driven back to the Tower for supper.

On 18 February a real treat was seeing a wild Tamandua climbing through the forest trees next to the Tower first thing in the morning.

We spent the morning walking the Plantation Trail which is accessed from the bottom of Semaphore Hill Road. Along the trail we saw White-tailed and Black-tailed trogons, a Broad-billed Motmot, a Crimson-crested Woodpecker, Chestnut-backed Antwrens, Western Slaty Antshrikes and an adult and a juvenile Sunbittern. On our return to the Tower we saw a Double-toothed Kite perched near the building.

In the afternoon, after a short visit to the Canopy Bed and Breakfast in Gamboa, we birded around the Gamboa Rainforest Retreat on the shores of Lake Gatun. Here we saw Variable Seedeaters, Greater Kiskadee, Gartered Trogon, and two Southern Lapwings along the lake shore.

On 19 February we spent the day along Pipeline Road, eventually having a picnic lunch several kiometres in at Rio Mendoza. Special finds included a Speckled Mourner, a rusty colored forest species that vaguely resembles a cross between a small thrush and a flycatcher. The Birds of Panama, A Field Guide categorizes the mourner, along with becards, tityras, piprites and the schiffornis as "incertae sedis" or of uncertain relationships within the passerine (perching birds). One thing that a person quickly learns about Neotropical ornithology is how much remains to be worked out. Take the tribe of woodcreepers for instance. There are many widespread species, like the Olivaceous Woodcreeper, that have several subspecies. In the case of the Olivaceous Woodcreeper there five groups of subspecies. Many of these populations look alike but have distinctive vocalizations. It is likely that as research continues the Olivaceous Woodcreepers, and several other species including the widespread Buff-throated Woodcreeper,  will be "split" into multiple species.

Our best bird of the 19th was, in my opinion, not the Purple-throated Fruitcrows nor the Black-striped Woodcreeper which were both good, but the Great Tinamou which Karl spotted as we were getting out of the vehicles at one spot. The bird was a couple of metres inside the jungle edge, all but invisible in its gray-brown plumage. It was absolutely still. Most of us managed to get decent photographs of the bird by searching for "tunnels" in the vegetation down which we could focus our lenses. I was also happy that we didn't flush the bird. It was still in its original spot when we finally drove away.

Other new birds included a strange flycatcher called the Brownish Twistwing, which turned out to be singularly well-named for it was brownish and it occasionally flipped one wing at a time up above its back, perhaps to startle insects into revealing their locations. Apparently at least four other flycatchers share this wing-lifting behaviour including the Ochre-bellied, Olive-striped, Sepia-capped and Slaty-capped flycatchers. Lunch was enlivened by a tanager flock that included Tawny-crested, Bay-headed, and Carmiol's tanagers. My big miss was dozing in Charlie's Toyota pick-up while the some of the people in the open-canopy birdmobile ahead of us spotted a Great Currasow fly off the road during our return to civilization.

Fig. 4 - The young orphaned Tamandua at the Summit Hill rehabilitation facility. Photo by C Siddle. 


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