Mercury: an increasing threat in the tropics

The rainforest is a highly diverse and complex ecosystem, of which only a very small percentage is known. Because the impact of different disturbances within it is not fully understood, protecting its integrity should be the end goal. However, the threats affecting this ecosystem are only increasing over time, including deforestation and mercury pollution caused by mining.

Mercury can be found in many forms, and while these are naturally available in the environment, a great amount results from its use in human activities like gold mining. Furthermore, although not all of its forms are toxic, methylmercury, the most bioavailable and toxic, bio-accumulates within the food chain, affecting a wide range of species. Bioaccumulation of this neurotoxin in birds has been seen to affect the fitness, coordination, reproduction and survival of species. Its effects include lethargy, loss of appetite, aberrant parenting behavior and reduced motivation to forage. Unfortunately, mercury’s persistence in the atmosphere and ability to travel great distances has allowed it to contaminate areas far from the original source.

Roadside Hawk (Rupornis magnirostris) and a boat carrying oil for mining share the same ecosystem. PC: Patrick Newcombe

Aquatic systems are most efficient at converting mercury to methylmercury, increasing the risk of aquatic species. Because of this, much of the attention and studies of mercury contamination in birds has been focused on species associated with bodies of water. Conversely, terrestrial habitats and their wildlife have received little attention. Variations in soil moisture are expected to increase the bioavailability of mercury; increasing the risk of the long, wide, and complex food webs found in tropical systems.

Diego Guevara, 2019 Franzen fellows,
is studying bird community in areas
impacted by mining.

Because birds are often near or in the top of food chains, they are highly prone to accumulating mercury in their bodies. However, this fact does also make them very good bio-indicators of environmental mercury contamination. They are common, conspicuous, and sampling of feathers and eggshells can confidently detect levels of heavy metals in a non-invasive manner. Particularly in tropical rainforests, more work needs to be done to assess the impact of mercury on birds.

The increasing threat mercury pollution poses to the tropics is drawing more and more attention to this region. As a short-term measure, it is necessary to replace current gold mining techniques, with already existing mercury-free methods. By moving away from this metal, we will ensure healthy human and wildlife communities and more crucially a healthy ecosystem.

Further readings:

Egwumah F.A, Egwumah P.O & Edet, D.I. (2017). Paramount roles of wild birds as bioindicators of contamination. Int J Avian & Wildlife Biol. 2(1):194‒200. DOI: 10.15406/ijawb.2017.02.00041

Appel, Peter & Jøsson, J.B.. (2010). Borax – an alternative to mercury for gold extraction by small-scale miners: Introducing the method in Tanzania. Geological Survey of Denmark and Greenland Bulletin. 87-90.


MAAP #101: Deforestation Continues in Columbian Amazon (2019)

Overflight photo of recent deforestation in Chiribiquete National Park. Credit: FCDS/RFN/AAF.

A major deforestation surge continues in the northwest Colombian Amazon (MAAP #97).

In 2018, it resulted in the loss of 199,000 hectares (491,700 acres)*, making it the most concentrated deforestation hotspot in the entire western Amazon (MAAP #100).

Here, we provide a real-time update for 2019 based on early warning GLAD alerts.** The alerts indicate the loss of 56,300 hectares (139,100 acres) in the first five months of 2019 (January to May) in the Colombian Amazon.

The Base Map (see below) shows the deforestation hotspots are again concentrated in the northwest Colombian Amazon.

We focus on Chiribiquete National Park, showing satellite imagery and overflight photos for two sections of the park experiencing recent deforestation.***

We estimate the deforestation of 2,200 hectares (5,400 acres) inside the Park since its expansion in July 2018.

As described below, one of the main deforestation drivers in the region is conversion to pasture for land grabbing or cattle ranching.





Conserving Palms to Conserve Tropical Birds

Los Amigos Bird Observatory | Cotingas, manakins, and toucans are among the many fruit-eating birds found in the tropical forest. Unlike the species in temperate zones, tropical bird species have evolved to depend on this resource year-round. However, fruits are a food supply that can be highly patchy in time and space. In areas with pronounced wet and dry seasons, fruit abundance typically peaks during the wet season and is lowest during the dry season. Now, with the end of the rainy season, the abundance is coming to an end. So what will the fruit-eating birds rely on?

Global Big Day at Los Amigos: 331 Species Sighted!

Exploring the trails of the station

The Global Big Day (GBD) is a date in which amateurs and experts in birds from around the world seek to see the greatest number of species in their locality. However, it is not only a date in which healthy competition between countries is observed, but also a great opportunity to educate about the diversity of birds worldwide. Like every year, at Los Amigos we were eager to participate in this event and give our best.

At the station, three bird guides from the regions of Madre de Dios and Cusco led this year’s GBD. Jose Luis Avendaño, Percy Avendaño and Cesar Bollatty have more than 20 years of experience touring Peru, including numerous visits to the station. Their knowledge of the species in the area and the station was key to end the day with a total of 331 species sighted, a new record for the station in a GBD.

On May 4, at 4:30 in the morning we were already on the trails in search of the most nocturnal species. Among them we recorded the Crested Owl (Lophostrix cristata), the Long-tailed Potoo (Nyctibius aethereus) and the Ocellated Poorwill (Nyctiphrynus ocellatus). The search for the various species of the station continued until 3:30 in the afternoon, when a heavy rain caused the forest to be silenced and we had to stop our search. After eleven hours of intense search, we are the second group with the most species sighted in Peru!

Although we could not spot species such as the Pale-winged Trumpeter (Psophia leucoptera) and the Cocoi Heron (Ardea cocoi), species commonly sighted in Los Amigos, we managed to spot other species not so easily observed in other places. The Pavonine Quetzal (Pharomachrus pavonivus), the Great Jacamar (Jacamerops aureus), the Royal Flycatcher (Onychorhynchus coronatus), the Spangled Continga (Cotinga cayana) and the Bar-bellied Woodcreeper (Hylexetastes stresemanni) are among the rare species that we spotted during this event.

A Long-billed Starthroat  (Heliomaster longirostris) spotted at the station. PC: Jose Luis Avendaño

Jose Luis Avendaño, Percy Avendaño y Cesar Bollatty after a long day of birdwatching. PC: Arianna Basto.

The Global Big Day 2019 was a great day for Los Amigos. Everyone who participated had a great day, enjoying the diversity offered by the station and always learning a little more. I’m sure the birders around the world enjoyed May 4th as much as we did at the station!

MAAP #99: Detecting Illegal Logging In The Peruvian Amazon

New logging road in the Peruvian Amazon. Data: Planet.

In the Peruvian Amazon, most of the logging is selective (not clearcutting), with the targets being higher-value species. Thus, illegal logging is difficult to detect with satellite imagery.

In MAAP #85, however, we presented the potential of satellite imagery in identifying logging roads, which are one of the main indicators of logging activity in the remote Amazon.

Here, we go a step further and show how to combine logging road data with additional land use data, such as forestry licenses and concessions, to identify possible illegal logging.

This analysis, based in the Peruvian Amazon, has two parts. First, we identify the construction of new logging roads in 2018, updating our previous dataset from 2015-17 (see Base Map).

Second, we analyze these new logging roads in relation to addition spatial information now available on government web portals,* in order to identify possible illegality.

*We analyzed information on several websites now available from national and regional authorities, such as SISFOR (OSINFOR), GEOSERFOR (SERFOR), and IDERs (Spatial Data Infrastructure of Regional governments). These new resources provide valuable information, however, may have limitations in ability to constantly update information on the status of concessions and forest permits.

Two Ancient Icons of the Neotropics

The Harpy Eagle (Harpia harpyja) and the Shihuahuaco tree (Diptheryx micrantha) are iconic species of the Neotropics that play key roles in the health of the ecosystem.

The harpy eagle is the heaviest and most powerful raptor inhabiting the canopy of rainforests. Its historic distribution ranges from southern Mexico to northeastern Argentina. While the variety in its diet suggests an opportunistic foraging behavior, it feeds mostly on arboreal mammals.

The mighty harpy eagle (Hapia harpyja) occasionally needs a break. Picture taken at Los Amigos Birding Lodge. PC: Rich Hoyer

Already hard to spot in the wild due to hunting and habitat loss, the harpy eagle population has plummeted in many countries of Central America.  An obstacle to its recovery is its slow reproductive rate: the eagle generally breeds every two to three years, with a single offspring per nesting effort.

A single shihuahuaco (Diptheryx micrantha) tree might sequester a third of all carbon stored in a hectare of primary forest. PC: Gianella Espinosa – Arbio

The shihuahuaco, meanwhile, is an emergent tree of the canopy that can reach a height of over 50 meters. It is patchily distributed in South America from Colombia to Bolivia. Shihuahuaco seeds and fruits are a source of food for species such as bats, agoutis, macaws, and hawks.

The slow-growing shihuahuaco can take centuries to reach its maximum height. Though not classified as endangered, it is critically threatened by logging and deforestation. In Peru, due to its hard wood and resistance to rot, the shihuahuaco is one of the most exported timber species, both legally and illegally.

Deforestation is the two species’ common destroyer: it has decreased the availability of prey and nesting sites for the eagle, while reducing disperser populations and suitable habitat for the shihuahuaco.

In a forest, the absence of large predators is associated with decreased tree diversity. The harpy eagle helps controls the presence of herbivores and thus enables many tree species to propagate. While standing, the shihuahuaco is an ecologically important species due to its broad buttresses that give structural integrity to the forest; when it falls, it leaves large gaps, facilitating successional forest growth. Further, because of the large amount of carbon a single shihuahuaco tree can store, it is a key species to fight the effects climate change.

One of the many shihuahuaco (Diptheryx micrantha) seedlings being planted throughout the station. PC: Arianna Basto

Because of its great size, for nesting, the harpy eagle depends on emergent trees of the canopy, one of the most important being the shihuahuaco. Locals and researchers have described the close relationship between these two species. Notably, eagle nests built on shihuahuaco branches will serve for more than one reproductive season.

At Los Amigos, we are planting over a hundred shihuahuaco seedlings. Eventually, the shihuahuaco will be a common sight here… and, with luck, so will the majestic eagle.

Further reading:

  • Aguiar-Silva, F. H., Sanaiotti, T. M. & Luz, B. B. (2014). Food Habits of the Harpy Eagle, a top Predator from the Amazonian Rainforest Canopy. Journal of Raptor Research, 48(1): 24-35. URL:
  • Putzel, L., Petersa, C. M. & Romod, M. (2011). Post-logging regeneration and recruitment of shihuahuaco (Dipteryx spp.) in Peruvian Amazonia: Implications for management. Forest Ecology and Management 261 (2011) 1099–1105. doi:10.1016/j.foreco.2010.12.036

Camera Traps: Colorfully Capturing Motmots

Our camera traps were set up to monitor a nest of the secretive giant armadillo (Priodontes maximus). However, during a recent recording session, a less reclusive forest friend stole the spotlight: a rufous motmot (Barypththengus martii). This curious bird belongs to the Momotidae family, which comprises a group of colorful arboreal species.

An Amazonian motmot (Momotus momota) showing off its racket-like tail. Photo: Will Sweet

Endemic to the tropics, among birds of the region, the motmots range in size from medium to medium-large. Despite their bright plumage—a combination of greens, blues and rufous (rust-like) colors—they are hard to spot. Most of the species have a long tail, and a few have two longer feathers that have racket-like tips. In contrast with many other bird families, motmots exhibit no sexual dimorphism: males and females look much alike, though on closer inspection males tend to be larger and have longer tails.

Spotting a motmot can be challenging because they sit still for long periods. They can be observed when they sally out to catch their prey, or through the sideways movement of their tails. It has been hypothesized that the turquoise-browed motmot (Eumomota superciliosa) uses this latter movement to signify to a predator that it has awareness of its presence. Thus advised, the predator might desist from an attack, preventing an unnecessary waste of energy on both sides.

Motmots can be found in a variety of forest types, from lowland tropical forest to template forests. Some species can even adapt to man-made habitats such as plantation and gardens. Motmots take their prey from leaves, twigs or branches of trees or other vegetation, and can be seen on the ground too. Smaller species feed on insects while larger ones additionally feed on other invertebrates, small vertebrates and fruits. The larger species like the Amazonian motmot (Momotus momota) and the rufous motmot have been reported to feed on bats and on poison dart frogs, respectively, in the latter case with no apparent harm to themselves.

A rufous motmot (Barypththengus martii) inspects a burrow of the giant armadillo (Priodontes maximus).

 Most of the Momotidae have similar breeding behaviors. An exception is the tody motmot (Hylomanes momotula), which is also morphologically atypical and the most primitive species of the family. These ground-nesting birds use their feet to loosen the soil to later dig their nesting burrows. Both mates share this work and the chick rearing. Motmots are solitary nesters, but when limited suitable space is available, they may concentrate in groups. A new burrow is dug for each nesting season, often close to the previous burrow. As our camera trap and other studies have reported, the rufous motmots also use old burrows of armadillos and other mammals to nest.

Like many other Neotropical birds, the motmots are understudied, and there are much more to learn about them. Who knows which other surprises they may hold!

Further readings:
Skutch, A. F. (1971). Life History of the Broad-billed Motmot with Notes on the Rufous Motmot. The Wilson Bulletin Vol. 83, Nro 1.
Murphy, T. G. (2006). Predator-elicited visual signal: why the turquoise-browed motmot wag-displays its racketed tail. Behavioral Ecology.


New Year, New Fellows! Announcing the 2019 Jonathan Franzen Fellows

Two years ago, the Los Amigos Bird Observatory opened its doors to promote avian research and conservation in one of the most biodiverse ecosystems in the world: the Amazon basin. To continue with our commitment, last year, we launched our second Franzen Fellowship call for applications, targeting students and young researchers interested in avian research. The group of promising and highly qualified candidates that applied made this a tough decision. We congratulate all the candidates, and are excited to present our 2019 Franzen Fellows!

Jessica Pisconte holds a degree in biology from the Universidad Nacional San Luis Gonzaga de Ica, Peru. Her interest in avian conservation was born in the Paracas National Reserve, after which she joined a wide range of research projects to learn about the importance of birds in coastal, mountain and Amazonian ecosystems. She is currently working as a park ranger in the Tambopata National Reserve in Peru’s Madre de Dios region. As the threats due to illegal mining increased in this region, seriously affecting the environment, Jessica was motivated to research key areas to understand its impact. Los Amigos will be her starting point to study the effects on birds of mercury from gold mining. Through this project, Jessica seeks to contribute to the conservation of and knowledge regarding birds in the Peruvian Amazon.



Lisset Goméz studied biological sciences at the Universidad Mayor de San Marcos in Lima, Peru. Her interests include ecology, reproductive biology, and conservation of bird communities, and she has been involved in a number of courses and projects around Peru that embrace these topics. Lisset volunteered with the National Service of Natural Protected Areas (SERNANP) and at the Wayquecha Biological Station, where she assisted in a project on plant-hummingbird interactions.  Through her participation in the Course on Field Techniques and Tropical Ecology at the Cocha Cashu Biological Station in Manu National Park, she strengthened her knowledge of the tropical forest and started conducting her own research. As a Franzen Fellow, she will try to understand the habitat requirements of woodpeckers of the genera Campephilus and Celeus. She will address her research question by identifying the woodpecker species’ tree preferences when excavating their nesting cavities.


Diego Guevara got his biology degree from the Universidad Nacional Agraria La Molina (UNALM) in Lima, Peru and holds a master’s degree in applied ecology from the University of East Anglia, UK. He is an associate researcher at the Centro de Ornitología y Biodiversidad (CORBIDI) and general coordinator of the UNALM banding station. He has experience in projects related to the impact of human activities on biodiversity, with a special interest in the responses of bird communities and the habitat requirements of endangered species. Additionally, he is interested in studying the ecotoxicology and physiology of birds, which led him to apply to the Franzen Fellowship. His project will focus on the fluvial and bamboo forest bird community, studying the impacts of mining on its bird communities.



Patrick Newcombe attends the Sidwell Friends School in Washington, D.C., making him the youngest of our fellows. His interest in birds started as a young child, leading to his engagement in bird research. In 2018, with Osa Conservation in Costa Rica, he collected field data on the flocking behavior and diet of the endangered black-cheeked ant tanager (Habia atrimaxillaris). He is currently analyzing weather surveillance radar data to study the flight strategies of migratory birds on the Pacific Flyway as part of a project led by Dr. Kyle Horton from Cornell University. At Los Amigos, his project will focus on Manakin leks around the station, from which he will identify and learn about their habitat use patterns.

Stay tuned to learn more about our Fellows and their projects!


Joining forces with neighbors? Think twice!

The russet-backed oropendola (Psarocolius angustifrons) is one of the most common and widespread of the oropendola passerine birds in the Amazon. They are mostly dull brown with rufescent rump and olive tone to head. This species has three subspecies: P. a. astrocastaneus, on the western Andean slope; P. a. alfredi in the eastern Andean subtropical forest; and P. a. angustifrons in Amazonia. These subspecies differ primarily in bill and face coloration and vocalizations. During the breeding season, they are seen arduously building their characteristic basket-like nest that hang from tree branches in riparian and second-growth habitats. These closed nests keep their eggs and chicks protected from predators.









Russet-backed oropendola (Psarocolius
angustifrons) and violacious jay (Cyanocorax violaceus) scaring away intruders. PC: Tom Matia

The violaceous jay (Cyanocorax violaceus) is a colorful and gregarious member of the crow family of northern South America. This jay species is predominantly dark violet-blue, with a black facial mask. The violaceous jay can be found in a variety of forest habitats, including degraded forest, but is especially common along riparian corridors and forest edges. They are omnivorous and can be seen eating fruits, insects and bird and reptile eggs.

A great contrast is easily noticed between the species: some think that the call of the russet-backed oropendola sounds like water drops, while that of the violaceous jay strikes some as similar to a car horn. The species also have similarities: they are conspicuous resident and widely distributed species in the Amazon.

Brown capuchin (Cebus apella) might look cute but
they are fierce predators. | PC Claudia Rohr

These species have something else in common: confrontations with brown capuchin monkeys! Brown capuchins (Cebus apella) feed mostly on fruits and invertebrates, but from time to time enjoy a meal of bird eggs and chicks. Quite often, a group of these monkeys can be seen climbing up the trees right outside the office at Los Amigos, where the oropendolas and jays are nesting close to each other. When the brown capuchins arrive, adults of both bird species first make their presence known with their characteristic calls. When the monkeys draw close to the nests, the oropendolas and jays cooperatively try to chase them away. These encounters conclude with either the monkeys leaving empty-handed or the birds suffering broken nests and lost eggs.

The striking cooperation between these bird species is short-lived. Jays will try to take eggs and chicks from other bird nests, including fiercely defended russet-backed oropendola nests.  For the oropendolas and violaceous jays, the expression “the enemy of my enemy is my friend” is applicable only when the common enemy is visible.


MAAP #95: Oil Palm Baseline for The Peruvian Amazon

In previous reports, we have documented that oil palm is one of the deforestation drivers in the Peruvian Amazon (MAAP #41, #48). However, the full extent of this sector’s deforestation impact is not well known.

High-resolution satellite image of oil palm plantation in Peruvian Amazon. Imagery: DigitalGlobe. Click to enlarge.
High-resolution satellite image of oil palm plantation in Peruvian Amazon. Imagery: DigitalGlobe. Click to enlarge.

A newly published study assessed the deforestation impacts and risks posed by oil palm expansion in the Peruvian Amazon. Here, we review some of the key findings.

We first present a Base Map of oil palm in the Peruvian Amazon, highlighting the plantations that have caused recent deforestation. We then show two zooms of the most important oil palm areas, located in the central and northern Peruvian Amazon, respectively.

In summary, we document over 86,600 hectares (214,000 acres) of oil palm, of which we have confirmed the deforestation of at least  31,500 hectares for new plantations (equivalent to nearly 59,000 American football fields).

In other words, yes oil palm does cause Amazon deforestation, but not nearly as much as Asia.