The Torrent duck (Merganetta armata) is an aquatic bird, specialized for life in fast-moving mountain rivers.  The distribution of its three subspecies includes the Andes of South America from Venezuela to Chile: Merganetta armata armata is found in Chile and Argentina; Merganetta armata leucogenys is distributed from southern Ecuador to northern Chile; and Merganetta armata colombiana is found in Venezuela, Colombia and northern Ecuador (Fjeldsa & Krabgbe 1990).

 

In Venezuela, the Torrent duck is distributed from the northern part of the state of Mérida to southwest Táchira.  Its distribution has been found to be associated with fast-flowing mountain rivers at altitudes between 2000 and 2800 m (De Schauensee & Phelps 1978, Gomez-Dallmeier’s & Cringan 1989), within the ecological units of cloud forest, low mountain forest, high mountain forest and Páramo (Sarmiento et al. 1971).

 

Concerning food habits little is known about the exact composition of the diet and the possible fluctuations during the year. The Torrent duck eats stonefly larvae, mollusk including gastrops, and occasionally traces of vegetable material. To feed they will dive, swim submerged, forage among vegetated rocks, and will also stand at the bottom of small falls and feed in the cascade of water.

 

The Torrent Duck have long-term pair-bonds. The nest may be hidden in various waterside cavities, but few have been found. Recorded sites include cliff ledges and crevices or rock ledges lined with down. The torrent duck lays 2 dull buff eggs with possibly the longest incubation period in the Anatidae family (Scott 1954, Gomez-Dallmeier’s & Cringan 1989, Callaghan 1998).  In Venezuela the Torrent Duck reproduction season is during the dry season between November and May. No study of the nesting success of the Torrent Duck has been conducted in Venezuela. No predators are Known and principal cause of mortality may be when chicks are swept down stream in the river (Gomez-Dallmeier’s & Cringan 1989, Callaghan 1998)

 

Indications have been found that populations of the Torrent duck are diminishing, according to Ellis-Joseph and others (1992), the three subspecies are considered Endangered.  These authors have suggested including Merganetta armatta colombiana, the subspecies found in Venezuela, among priority species in need of special attention.

 

Due to the fact that the Torrent duck is a species locally distributed in restricted areas, its populations will naturally consist of only a few individuals, putting the total population of this species in Venezuela between a minimum of 100 and a maximum of 1500 individuals (Rodríguez & Rojas-Suárez 1999).  Furthermore, human interventions such as settlements that further restrict potential habitat, agricultural practices that contaminate water and reduce food sources; deforestation which favors the frequency and intensity of river flooding, destroys nests and increases mortality.  Construction of  dams / reservoirs which reduces the suitable habitat area; and introduction of exotic fish such as Rainbow trout that increases interspecific competition for food source (Gomez-Dallmeier’s  & Cringan 1989, Fjelsa & Krabbe 1990); can decimate populations and even extinguish local populations

 

There are no studies providing information about the actual state of the population of Merganetta armatta colombiana in the Venezuelan Andes. Therefore, it is a priority to identify the ecological aspects and environmental factors affecting population density, distribution, and reproduction in the state of Mérida.  The results of this research will provide information on which to base management and conservation programs.

 

 

1.- To determine the distribution of Merganetta armatta colombiana in the state of Mérida, by means of monitoring along the principal high mountain rivers of the state.

 

2.- To evaluate the state of the populations of this subspecies in the state of Mérida, through estimates of population density.

 

3.- To characterize and evaluate the habitat of Merganetta armatta colombiana, by means of field observations, water quality analysis, determination of the water volume and river beds.

 

4.- To study through field observations the reproductive aspects that yield knowledge of population dynamics of this species.

 

5.- To determine the diet of the Torrent Duck during the year, by analysis of fecal samples.

 

 

This study will be confined in mountain rivers and their principal affluents located between 2000 and 2800 m, including the upper part  basin of the Río Chama, Río Santo Domingo, Rio Nuestra Señora, and  Río Mucujún of  Mérida state.

 

 

The past decades remaining populations:

 

Location	Taxon	Dates	Status
Southwest Táchira	M.a. colombiana	?	?
Cordillera de Mérida	M. a. colombiana	2000-2002	Extant

 

                      

           

 

The study area includes a reservoir of fresh water which plays a key role in the hydrology of a vast region. In addition of having a high biological diversity, with birds populations that are of particular conservation concern.

For over a decade, widespread, long-term declines in many bird populations have been noted and are a source of growing concern. In particular, population declines of many waterfowls have caused alarm.  The loss, degradation and fragmentation of habitat contribute significantly, both directly and indirectly, to avian population declines.

The Torrent Duck project will develop and implement conservation plans using the information gathered during the research program, with the benefit of involving local communities to promote environmental awareness.

 

 

 

 

1.-To promote public interests for the Torrent Duck conservation and establish the basis for a regional environmental education program.

 

2.-To produce and distribute educational material on the biology and ecology of the Torrent Duck, based on local information gathered by the research program.

 

3.-To increase awareness among governmental officials on the importance of enforcing existing wildlife conservation laws and habitat protection.

 

 

-Carlos Rengifo G, “La Mucuy” Bird Observatory, Main researcher (contact person), University of the Andes, Curator of Bird Museum (CVULA).

- Karina Sanchez (Cooperating scientist), Postgraduate student, University of the Andes, Mérida, Venezuela.

-Alirio Nava (Field assistant),  Instituto Tecnologico de Ejido, Mérida, Venezuela.

-Mario Zambrano (Field assistant), Student, Universidad de los Andes. President of “La Azulita ” Birding Club.

 

 

Callaghan, D.A. (1998). Conservation status of the Torrent Ducks Merganetta. Wildfowl 48:166-173.

 

De Schauensee,  R. M. & W. H. Phelps, Jr. 1978. A Guide to the Birds of  Venezuela, Princeton University Press,  New Jersey.

 

Ellis-Joseph, S.  N. Hewton & A. Green. 1992.  Global Watrfowl Conservation Assessment & Mangment Plan. First Review Draft.  Captive Breeding Specialist Group (CBSG/SSC/IUCN), The Wildfowl & Wetlands Trust. 77 pp.

 

Fjeldsa, J & Krabbe, N. 1990. Birds of the High Andes,  University of Copenhagen.  Apollo Books. Svendborg. Denmark. 876 pp.

 

Gomez-Dallmeier’s, F. & Cringan, T. M. 1989. Waterfowl in Venezuela, Editorial Ex Libris, Caracas. Venezuela. 351 pp.

 

Rodríguez, J.P & Rojas-Suárez, F. 1999. Libro Rojo de la Fauna Venezolana. Provita. Editorial Ex Libris. Caracas. Venezuela. 472 pp.

 

Scott, P. (1954). Behaviour of the Bolivian Torrent Duck. Wildfowl Trust Ann. Rep. 6:69-72.

 

Sarmiento, G., Monasterio, M., Azócar; A., Castellano, E., Silva, J., Flores, E., Trejo, D. E. y J. Briceño. 1971. Estudio Integral de las Cuencas Chama y Capazón. Sub-Proyecto NºIII. Vegetación Natural. U.L.A. Mérida, 63 pp.

 

World Conservation Monitoring Center. 1992. Global Biodiversity. Chapman and Hall, London. 585pp.