Birdernaturalist: April 2018

In October and November, of this past year I had a tour-free period to conduct three scouting trips to Bolivia and Brazil.

Bolivia is a big county with a unique position in South American geology, draping several continental watersheds and therefore partaking in more ecoregions than any other country. As a result, it has the greatest biodiversity of any landlocked country in the world. Amazingly, it’s still has the oldest democratically elected government in South America, despite its well-earned reputation for sudden and violet regime changes in the now distant past. I have long wanted to offer a second Bolivia tour to augment the standard one that I’ve been leading for the past 17 years (which starts in Santa Cruz and visits the northern Chaco, the endemic Valle Region, and then the central Andes near Cochabamba) even though it’s still a great tour on its own. My new tour that I’m scouting for will visit the Llanos de Moxos (a great tropical plain that eventually drains into the Amazon), the Andean valleys of Lake Titicaca and Apolo, and a new lodge on the brink of Amazonia and the outermost ridges of the Andes.

My new tour (taking place in late 2018, already almost full) will actually take the reverse route from my scouting trip detailed below, which began with a regular commercial flight from Santa Cruz de la Sierra, followed by two puddle jumpers. The first of the two short Cessna flights was from the city of Trinidad to Santa Ana de Yacuma. Trinidad is no metropolis, but it’s the largest city for many miles.

Not far from town, I was salivating at the habitats below. New species of birds – the most studied group of animals in the world – have been found here in recent years, and rumors of even more found very recently are being whispered. How many species of other taxa have gone undetected in this understudied region?

I had a bit of time in Santa Ana de Yacuma to wander around while my next flight was being negotiated. Blue-winged Parrotlets were in the trees by the airport.

These trees seemed to be quite attractive to several birds and other critters. It turned out to be a very good tree for wildlife in general during this season. It is Curatella americana, in the (to me) unfamiliar family Dilleniaceae.

There was a wet ditch (we’re at the very start of the rainy season here) with some interesting water plants. This is one of the water-hyacinths, Pontederia rotundifolia.

This is Utricularia foliosa, in the bladderwort family Lentibulariaceae.

A Cattle Tyrant in a classic pose on a horse.

On the flight from Santa Ana de Yacuma to Barba Azul Nature Reserve I was excited to see the hints of the agricultural activities that predate European contact with South America, discussed in some detail in the book titled 1491: New Revelations of the Americas Before Columbus by Charles C. Mann.

Here’s a view of the Barba Azul Nature Reserve shortly before we land, showing the wetlands of the Omi River, drier grassland, and just a bit of palm island habitat.

Our landing strip is in the middle of nowhere, but there is actually more than meets the eye here. One can actually drive here during the dry season (ending soon), but it’s a very long, bumpy dirt road.

There used to be an active cattle ranch here, and there are still huge ranches that surround this property, but this is now a preserve and research area, welcome to ecotourists. This is the cabin I stayed in.

The headquarters and cabins are situated right on the banks of the small river which is essentially a tropical freshwater marsh. I heard, recorded, and glimpsed Yellow-breasted Crake (a “mega” for Bolivia) just down from here.

This Hippeastrum (known as “Amaryllis” in the florist lingo) is a native flower in the drier woodlands.

The main conservation goal is the Blue-throated Macaw, which gathers here in the non-breeding months to feed on palm fruits and seek shelter in predator-free islands of trees in the vast plains. I saw flocks of them over the distant trees shortly after arriving, and a quick boat ride to the opposite side of the Omi River brought us to these perched birds.

There is so much more to see here than just the macaws (which are indeed here in larger numbers than anywhere else, but they are free to fly away and sometimes are elusive). On that afternoon, just a short walk from the macaws was this Giant Anteater.

We were just across the river from the cabin where I was staying.

My lifer Sharp-tailed Tyrants were very close by in a patch of native grass that hadn’t burnt in a couple years.

Another grassland specialty here, needing native grasses that haven’t burned in several years, is the fancy Cock-tailed Tyrant.

It was another lifer for me, and I stumbled through the tropical grasses to get better views, while the bird circled me and ended up closer to Tjalle, the Dutch manager of the reserve who had stayed on the fire break/trail.

There is just a bit of topographical variation here, enough to harbor several kinds of grassland as well as some islands of tropical palm woodland and cerrado-like scrub. The cabins are on the edge of such a large palm woodland, and right by my cabin was a fruiting fig that was immensely popular with a wide variety of birds.

Tanagers, flycatchers, vireos, and this Blue-crowned Trogon were attracted to the fruits.

Crimson-crested Woodpecker was a surprisingly regular resident of the palm woods.

I had a blast wandering the trails through the woodland and various grassland habitats. One of the fun surprises was a Yellow-green Vireo, a recent arrival from the north and the first record for the reserve.

These spiny leafhoppers in the family Membracidae, looking more like tiny aliens, were on the underside of a leaf in the understory.

When returning to my cabin one afternoon I came across this Boa constrictor crossing the path.

It seemed to enjoy my attention. Or at least it didn’t feel threatened enough to strike when I held it.

This gorgeous Erythrolamprus taeniogasterwas equally unperturbed by my hands-on approach.

The ranch hands had found it, kept it from escaping until they could get our attention, and then when I picked it up they kept their distance, being very afraid of any snake.

Though it may eventually be split as a different species, this frog from here is currently known as Leptodactylus chaquensis (thanks to Steffen Reichle for the ID).

The second part of my Bolivia scouting trip involved a very similar flight from the Barba Azul Reserve, but continuing westward to San Rosa de Yacuma.

From here I got a two-hour taxi down what used to be a narrow, dusty road but is now a vast construction project to convert it into a super highway, funded and built almost entirely by the Chinese, who are in the process of buying Bolivia and its natural resources. By the late afternoon I was on top of the outermost ridge of the Andes where one can look eastward over the plains of the Llanos de Moxos or westward over the Tuichi basin towards the ever higher ridges of the main Andean chain.

Sadiri Lodge is uniquely situated in this most amazing of habitats – an outer ridge of the Andes, which in most areas is very remote and inaccessible. You can drive here, though the road up the slope is a bit rough in places once you leave the main highway. Furthermore, they have lovely cabins built right in the middle of the forest. I had a Banded Antbird singing right outside my cabin the first afternoon.

The habitat here is essentially rainforest – such a contrast to the tropical grasslands a short distance away. As an expected result of the increased rainfall and topographical variety, the biodiversity skyrockets. Moths at the evening lights are fun. This is the silk moth Epia muscosa.

James Miller has revolutionized the world of moth ID by allowing amateurs like me to identify Dioptine moths such as this as Scotura annulata. It used to be known by several other names before his 2009 work and is unusual among members of the subfamily Dioptinae in being common and very widespread, even occurring as far north as southernmost Texas.

No one has stepped up to revise the genus Opisthoxia as of yet, so this moth shall remain undetermined to species for the time being.

Most katydids are green and leaflike, but the genus Vestria has some distinctive colorful highlights.

Butterflies weren’t overly abundant during my visit, but I saw a few. This hairstreak is the little-known Badecla lanckena.

Better were the herps. This frog is Oreobates cruralis, La Paz Robber Frog, identified with the help of sound recordings, which I posted to iNaturalist here: https://www.inaturalist.org/observations/9331422

The same can be said for this little Cuzco Robber Frog, Pristimantis danae. Sounds at https://www.inaturalist.org/observations/9331436.

One of my more surprising finds was this lizard Tropidurus melanopleurus. It turns out to be one of the most sexually dimorphic reptiles known. This is the rather unassuming male.

He was courting this gorgeously patterned female.

The short video is here:

This tiny “microteiid” lizard (family Gymnophthalmidae) is Cercosaura argula.

Plant diversity is high here, but I usually have no idea what I’m seeing until I can do research later and get expert id’s. This orchid was identified for me as Cattleya luteola.

I know this as a member of the family Gesneriaceae, and therefore a relative of the familiar African Violet. It is Corytoplectus speciosus.

There are just a few species like this in the genus Heliconia that have pendant, upside-down inflorescences, an adaptation to pollinators like the Buff-tailed Sicklebill, which surely occurs here, even if very rarely seen.

On of the more exciting birds I saw here was this Sulphur-bellied Flycatcher, a recent migrant from its breeding grounds to the north.

This White-lored Tyrannulet is probably a common resident, but rarely seen so well as it usually lives in the tall canopy.

I was amazed at the number of Yellow-shouldered Grosbeaks I saw and heard here. It’s a rare participant in mixed flocks throughout southern Amazonia but seems to be common at this location.