Explorer´s Inn Newsletter - February 7 March 2009

Explorer’s Inn Newsletter is produced by the Resident Naturalist volunteers at Explorer’s Inn.  More information about the Resident Naturalist Program including some of the volunteers' tasks and duties and a short introduction of the people who are currently partaking in this program can be found on the final page.

In this issue:

• Recent Sightings, the pick of the most exciting
• Sexual Selection, the evolution of the sexy
• Baby Snatchers, the darker side of the toucan
• Colpita Research, eating dirt isn’t just for pregnant women
• Bird Evolution, new research on the origins of modern birds
• RAINFOR, fighting global warming one tree at a time

Recent Sightings

Jaguar Seen from Boat
A Jaguar was sighted on the journey up from Puerto Maldonado by a boat of guests on there way to Explorers Inn. The large cat was seen resting under a bush on the river bank, before slowly walking down towards the river and then disappearing in to the jungle.

Jaguar (Panthera onca) the only very large spotted cats in the New World, the second biggest – ocelot (Felis pardalis) is much smaller. From whole of the world, only tigers and lions are larger. Body length is 1.1 – 1.9 m and weight is from 31 to 158 kg. Males are usually larger than females.

Armadillos Spotted Close to Lodge
Rainy season seems to be a good time for spotting armadillos, judging by the four sightings in December and January.  Three baby nine banded armadillos were spotted twice on successive days in December by RNs and a researcher working on Capirona and La Torre trails.  An adult nine banded armadillo was seen in January on La Torre trail by guide Listen and guests on a night walk, and another night walk revealed a giant armadillo to guide Alan and his guests.

Sexual selection at Explorer’s Inn

Visitors to Explorers Inn may have noticed the striking differences between male and female animals of the same species, with males outshining their mates with their splendid colouration and larger size.  This difference between the sexes is known as sexual dimorphism and can be noted in animals, particularly birds such as the silver beaked tanagers and the trogons around Explorers Inn.

Sexual dimorphism is a direct result of sexual selection, an evolutionary process which, is driven by the competition between individuals of one sex (usually males), for matings with the other.  Unlike natural selection it is not a case of survival of the fittest, but of who can mate with the most females.  The cost to poor competitors is not death, but few offspring to carry their genes to the next generation.  This process, which was initially highlighted by Darwin in 1859, has allowed characteristics such as bright colouration, ornamental feathers, songs and courtship dances to evolve in males, despite the fact that they have few survival benefits and in some cases may even hinder an animal’s escape from predators. 

Males can compete for mates in two ways.  Firstly they can compete directly with one another in physical jousts, which has resulted in some males evolving a larger size and weaponry such as the horns found on male rhinoceros beetles and the antlers of brocket deer.  They can also compete indirectly with each other for the females’ attention, by displaying bright, ornamental plumage or colouration, and by performing songs and courtship dances, which attract females.  Brighter sexier males will be better competitors, attracting more females and passing on more of their genes to the next generation, which in turn will contain more sexy, bright individuals.  Over time, males have evolved to be far more spectacular, whilst females who do not compete have remained dowdy and dull in comparison.

Why do males compete for females and not vice versa?  Males can produce large numbers of sperm and can mate with numerous females, producing many offspring and increasing their chances of passing on their genes to future generations.  Females on the other hand can produce and nurture only a limited number of eggs and therefore mating many times is unnecessary and in some cases even harmful.  They can ensure the survival of their genes by being picky and choosing the strongest healthiest males to father their young.  It is thought that many male traits such as bright plumage and the dancing performed by Peru’s national bird the cock of the rock, and Explorers Inn’s own manakins, are indicators of male quality and health.  In some species, such as macaws, females and males are monogamous and both sexes help feed and rear the young.  In these cases, where each sex invests equally in the chicks, both sexes compete for each other and male and female birds are identical in size and plumage.

In a few rare scenarios it is the females who compete for males.  The wattled Jacana can be found on Cocococha and Katicocha lakes and on the swamp on main trail.  Females of this species mate with many males, who incubate and rear their numerous clutches of eggs.  In this scenario, it is the males who are the source of competition for the females.  The females are therefore larger and have more accentuated red wattles than their mates.
Sexual selection has resulted in some of the most spectacular colours and beautiful songs present in the natural world.  The animals around Explorer’s Inn provide us with perfect examples.  So whilst you are looking around, you may find yourselves admiring the results of millions of years of evolution by sexual selection, the struggle to be the sexiest. YRL

Darwin C (1871) The descent of man, and selection in relation to sex. Edited by Murray J,
London.

Toucan Raiders

Toucans are some of the most iconic symbols of the Amazon and the several species found here (including their relatives the aracaris and toucanets) are a much sought after and impressive sight for visitors to Explorers Inn. A lesser known aspect of these birds is the more grizzly side to their diet, which along with fruit includes the eggs and young of other birds and even sometimes baby monkeys.
The Toucans` more bloodthirsty behaviour is something that the Yellow-rumped Caciques, which inhabit the distinctive pendular nests in the palm tree beside the football pitch, are well aware of. This is because these small yellow and black birds are the victims of repeated merciless raids by a pair of large White-throated Toucans on the hunt for eggs and nestlings.

The pair have frequently been seen arriving at the tree and tearing at the Cacique nests with their large powerful bills, often causing the intricately woven structures to fall to the ground bellow, chicks and all. The evidence of this can clearly be seen scattered on the grass below the palm. The Toucans will often keep up these raids for quite some time, impervious to the cacophony of noise produced by the alarmed Cacique parents. They finally depart only when they have claimed their gruesome prize or are chased off by several of the Caciques` more robust relatives, the Russet-backed Oropendolas, with whom they share their tree.

The Tambopata Macaw Project: Investigating the Mystery of Parrot Geophagy

The resident naturalists at Explorer’s Inn have joined forces with the Tambopata Macaw Project to better understand the local populations of parrots at the Explorer’s Inn Collpita.  The Tambopata Macaw Project, under the direction of Donald Brightsmith of Texas A&M University and Alan Lee of the University of Manchester, has carried out in-depth research on parrot ecology at several clay licks along the Tambopata River.  The partnership with the Tambopata Macaw Project represents a new chapter in the history of research at the Explorer’s Inn Collpita (1).

The Explorer’s Inn Collpita is one of many exposed cliff faces referred to as “clay licks” in the Tambopata region. Geophagy, the intentional consumption of soil, is common among mammals, birds, reptiles, and insects and has been documented on all continents except for Antarctica (2).  Avian species around the world have been observed eating clay, such as the African Gray Parrot in Africa, Crossbills in North America, and the Sulphur-crested Cockatoo in New Guinea (3).   In Peru, clay licks are often called by their Quechua name, “collpa”, which means “salty earth” – an appropriate name for these sites as they offer an important source of sodium to the geophagous animals that visit them (3).  The collpa near the Tambopata Research Center, which can be reached by a four-hour boat trip up-river from Explorer’s Inn, is considered to be among the largest clay licks in the world at 500 meters long and reaching up to 30 meters high (2).  Collpas in the Tambopata region attract seventeen species of parrots including Scarlet, Blue-and-Yellow, and Red-and-Green Macaws, among other birds and mammals (2).

The aims of the research at the Collpita are to monitor the population sizes of parrots in and around the Tambopata National Reserve and to explore the trends that exist in their use of clay licks.  In addition, behavior studies will be carried out on red-and-green macaws.

Geophagy among South American parrots
Geophagy has only recently received rigorous scientific investigation.  Dr. James Gilardi, now the director of the World Parrot Trust, investigated two potential reasons for parrot geophagy in Manu National Park and published his work in 1999 (3).  The first theory was that parrots eat soil for the minerals that it contains, while the second theory says that parrots eat clay to protect against the toxic chemicals in seeds (3).  Gilardi found that parrots preferred soils with lots of clay, but seemed almost indifferent to the concentration of minerals such as sodium and thus concluded that parrots consumed soil to coat the digestive system and protect against tannins and toxicity (3).  However, a more recent study on the Tambopata River by Romina Arumburú of the Universidad Nacional Agraria, La Molina in Lima said just the opposite.  Parrots had a very strong preference for soils with high concentrations of sodium and were indifferent to the amount of clay (3).  The resolution to these opposing conclusions lies in the tendency of some chestnut-fronted macaws and white-bellied parrots to consume high-sodium palm tree bark, but not clay (4).  In an area that receives so much rainfall as the Amazon basin, such a highly soluble mineral as sodium is quickly flushed through the soil, but is captured in the waterproof, high-clay content soils preferred by parrots (3).  The leading theory behind parrot geophagy in South America is that parrots consume soil for the sodium it contains, while the neutralizing qualities of clay are an added benefit, allowing parrots to exploit a wider range of food sources that includes seeds (4).

The importance of clay lick research
Clay licks offer a vital window into the world of parrots.  Parrots are difficult to study in the wild because they spend most of their lives in forest canopies and they regularly travel great distances (5).  Clay licks offer a setting in which parrots can be observed, allowing for regular monitoring of population sizes.  In previous studies, the number of macaws at a clay lick has been found to correlate to the to the abundance of macaws within a 25 square kilometer radius (6), and for this reason clay licks provide a population gauge that is easily accessible to scientists.  Monitoring the presence of this endangered bird family is crucial in Madre de Dios, a region that has experienced many recent environmental disturbances such as habitat loss, resource extraction, and increased traffic associated with tourism.

Clay licks also represent a crucial opportunity to support conservation, not only of parrots, but also of thousands of plants, animal, and insect species.  Eco-tourism is an important source of income for the residents of the Madre de Dios region and offers an alternative to logging and other forms of unsustainable land management.  A visit to a clay lick is among the top attractions for tourists to Explorer’s Inn and other lodges along the Tambopata River.  Entire ecosystems benefit from the beauty of these birds; while tourists may not travel from around the world to see rare beetles or trees, the revenue they bring protects these species nonetheless.  Adrian Forsyth and Ken Miyata explain in ‘Tropical Nature’ that “the key to sound conservation lies in protecting habitats and ecosystems.  Unfortunately, even people interested in nature find it difficult to get excited about habitats; their emotions, if not their concerns, center on specific plants or animals” (7).  The wall of dazzling, singing color created by the bodies of dozens of parrots at a clay lick engages the observer in dedication to an entire ecosystem.  GHK

References:

1. Shaw, E. M. 2008.  Activity, Behavior, and Interactions of Parrot Species at a Peruvian Clay lick.  Masters of Sciences thesis, Manchester Metropolitan University.
2. Brightsmith, D. 2004.  Effects of weather on parrot geophagy in Tambopata, Peru.  The Wilson Bulletin 116:134-145.
3. Brightsmith, D. 2003.  The real dirt on parrot clay licks. Bird Talk Magazine, October 2003.
4. Lee, Alan.  Personal communication, January 19th, 2009.
5. Brightsmith, D. 2006.  The Psittacine Year: What drives annual cycles in Tambopata’s parrots?  Prepared for the VI International Parrot Convention, April 2006, Loro Parque, Tenerefe, Spain.
6. Hume, E., Lee, A., Moore, D. 2006. Expedition Report: Surveying mammals, macaws, and other wildlife in the Peruvian Amazon.  Biosphere Expeditions.
7. Forsyth, A., Miyata, K. 1995.  Tropical Nature: Life and Death in the Rain Forests of Central and South America.  Touchstone, New York City, New York.

Major shake-up of bird evolution ruffles a few feathers

Birds are hugely species diverse filling a massive variety of ecological and environmental niches. Nowhere is this more apparent than here at Explorers Inn where it is possible to find 599 species of bird from giant carnivorous eagles to tiny nectar feeding hummingbirds, more variety than at any other site in the world (an official world record).
The early evolution of the various bird groups that has led to the massive diversity seen today is a highly contentious area of study and traditionally has involved grouping of species based on similarity of physical characteristics, food and approaches to feeding, types of habitat global location and finally the very limited fossil record.
The advent of modern genetic techniques has put a new and highly powerful tool into the hands of evolutionary biologists. Genetic sequence comparisons have enabled Rebecca Kimball and colleagues at the Field Museum of Natural History, Chicago, to reconstruct the path of avian evolutionary history for all existing birds. This has produced several important and unexpected conclusions that affect many of the bird groups found right here at Explorers Inn.
Falcons, such as kestrels and forest falcons, evolved into birds of prey entirely separately from hawks and eagles. Any similarities must therefore be due to convergent evolution alone, the coincidental evolution of similar adaptations by species sharing similar lifestyles, in this case hunting. In fact falcons are more closely related to parrots and passerines (perching birds or songbirds) than anything else.

The nightjars, a fairly unassuming group of nocturnal insectivorous birds are a far  more important group than they had been given credit for, responsible as they are for giving rise to two very different major groups of bird, the diurnal swifts and even more surprisingly, the flower feeding hummingbirds.
Meanwhile the Hoatzin which is common along the edges of oxbow lakes, such as our Cocococha, has confirmed its place in a family of its own. Highly unrelated as it is, to any other species.
The most unexpected and indeed controversial finding of Kimball`s study involves the humble tinamous, a distinctive group of mainly ground dwelling can be heard every morning and evening emanating from the forest around the lodge. Previously thought to be a separate distant group of birds, the new study placed them firmly amongst the ratites, a group who’s other occupants (the ostrich, rhea, emu and kiwi) are all famously and firmly flightless. However if you find yourself disturbing a tinamou as you walk along one of the trails you will undoubtedly notice that they are decidedly not. The tinamou, it seems, has achieved what is generally thought of as nigh on impossible by evolutionary biologists by revolving flight. JAB

RAINFOR at Explorer’s Inn: Measuring Amazonian Carbon Sequestration

As the world faces ever-increasing risk from the effects global warming, the human population continues to rise, new technology circles the Earth, and people become ever more reliant on carbon-emitting ways of life.  Although human activity has been significantly contributing to climate change for over a hundred years, the looming prospect of a warmer planet is only recently gaining widespread public attention.  In light of this problem, proper management of the Amazon forest is essential to the reduction of atmospheric carbon dioxide, a principal greenhouse gas. 

The Amazon rainforest is arguably the most crucial carbon sink in the world.   The six million square kilometers of tropical forest process 18 billion tons of carbon each year – more than double the carbon released by global fossil fuel emissions (1).  But even though it is so effective in purifying the atmosphere, Amazonia is just as vulnerable to global warming as the rest of the world’s ecosystems, not to mention the rampant deforestation that claims an alarming area of forest on a daily basis.  While the world depends on the Amazon to slow the rate of climate change, scientists lack a rigorous understanding of the sensitivity of its ecosystems and intricate carbon cycles.

The Universities of Leeds and Oxford in the United Kingdom responded to this information deficit in 2000 with the creation of the Amazon Forest Inventory Network (RAINFOR), an organization committed to illuminating the role of the Amazon forest as a global sink for carbon dioxide with unprecedented precision (2).  RAINFOR has partnered with scientists from Universities and organizations in Bolivia, Brazil, Colombia, Ecuador, Peru, Venezuela, Panama, Canada, the United States, France, the Netherlands, and the United Kingdom to acquire a detailed understanding of how the ecosystems of Amazonia may respond to climate change and the implications for international natural resource management and pollution control (2).

Together with their partners, RAINFOR monitor dozens of plots throughout the Amazon.  Among the oldest and best understood of these plots are those that were created at Explorer’s Inn/Tambopata National Reserve in 1983 by Alwyn Gentry (deceased), author of one of the most important field guides to Amazonian plant species and member of Conservation International’s Rapid Assessment Program (3).  Felix Filio Farfan Amezquita, Javier Silva Espejo, and Adan Cahuana Quispe, all from Universidad San Antonio Abad del Cusco, are RAINFORs representatives in Tambopata and visit Explorer’s Inn regularly to collect data (4).  Resident Naturalists Yasmin, Jack, and Georgia have worked closely with them to measure tree trunks, collect leaf litter, and map root systems to aid in their timely research.  GHK

References:

1. Phillips, O., Malhi, Y. 2007.  RAINFOR Project to study global carbon balance (Press release issued by the Gordon and Betty Moore Foundation).  (April 29th, 2009).
2. RAINFOR.  <http://www.rainfor.org> (January 29th, 2009)
3. Forsyth, A. B.  1993.  In: Gentry, A. H.  1993.  A Field Guide to the Families and Genera of Woody Plants of Northwest South America (Colombia, Ecuador, Peru) with supplementary notes on herbaceous taxa.  Conservation International, Washington, D.C.