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Brazilian merganser

Mergus octosetaceus

Baer's pochard female

Above: Brazilian merganser, at Zooparque Itatiba, Brazil (2018). Photo by Jan Harteman.

Recent records from Brazil indicate that this species's status may be marginally better than previously thought. Nevertheless, the remaining known population is still extremely small and fragmented, and the perturbation, damming and pollution of rivers are likely to be causing continuing declines. For these reasons, it is listed as Critically Endangered (IUCN, 2013). Further information on the population size (in particular whether it exceeds 250 mature individuals) and on the subpopulation structure may result in its downlisting to Endangered in the future.

Currently there are two ex-situ populations, one in Zooparque Itatiba (Brazil) and another one in Prague Zoo (Czech Republic), both populations managed by Zooparque Itatiba. 

Introduction in-situ

White-winged duck and Baer's pochard

Above: Three juvenile Brazilian mergansers, at Zooparque Itatiba, Brazil (2018). Photo by Jan Harteman.

The population was estimated at 250 individuals in 1992, and was thought likely to have declined since given ongoing threats, however there are recent suggestions that the population may exceed this figure (L. V. Lins in litt. 2012). Recent estimates from the three main areas currently known to hold the species are of 70-100 territories (140-200 mature individuals) in the Serra da Canastra area (L. V. Lins in litt. 2012, 2013), fewer than 50 individuals at Chapada dos Veadeiros (Disconzi 2012) and eight at Jalapão (IECOS Brasil 2013 per L. V. Lins in litt. 2013), but these figures require confirmation and the population is currently precautionarily maintained within the band 50-249 mature individuals.

 

It inhabits shallow, fast-flowing rivers, requiring rapids and clear waters. It occurs especially in the upper tributaries of watersheds but ranges into small rivers with patches of gallery forest surrounded by "cerrado" (tropical savanna) or within Atlantic Forest. It is non-migratory and does not abandon the stretch of river where it establishes its territory (Lamas 2006). Pairs have used 8-14 km stretches of river (Bartmann 1996, L. F. Silveira in litt. 1999), nesting in tree-cavities and rock-crevices (C. Yamashita in litt.2000, Lamas and Santos 2004, Bruno et al. 2010). Breeding activity has been recorded between June and August (Lamas and Santos 2004, Bruno et al. 2006, Bruno et al.2010), but timing may vary geographically. Incubation may last c.33 days (Bruno et al.2010). Young birds have been observed between August and November (Lamas and Santos 2004, Bruno et al. 2006). The diet comprises fish, small eels, insect larvae, dobson flies (Corydalis spp.) and snails. In Serra da Canastra it eats mainly lambari Astyanax fasciatus. Territory size is believed to be related to the number of rapids, edgewaters, water speed, fish abundance and conservation of riparian vegetation(Lamas 2006). Its dispersal ability is unknown, but one young male banded in September 2010 was found breeding on another river 20 km away in June 2011 (Ribeiroet al. 2011).

 

Perturbation and pollution of rivers results largely from deforestation, agricultural expansion and, in the Serra da Canastra area, diamond-mining (Bartmann 1994,Bartmann 1996, M. Diniz in litt. 2013). Previously, the species was thought to rely on gallery forest which, although protected by law in Brazil, has been cleared illegally throughout much of the species's range. However, evidence suggests it will occur on unforested, undisturbed stretches of river through cerrado. All recent records of the species in the Serra da Canastra region refer to unprotected sites north of the National Park. These are sites under increasing pressure from mining, development of hydropower infrastructure and agriculture (L. V. Lins in litt. 2013). Mining has ceased in the immediate area of its known range but there is no additional habitat for dispersing birds (L. F. Silveira in litt. 1999), and it is thought that diamond mining will resume at Serra da Canastra in the near future (L. V. Lins in litt. 2012). Expanding agriculture and the construction of hydroelectric dams are considered the principal threats to the species (Braz et al. 2003). Dam-building has already caused severe declines across much of its range, and is increasing in scale (L. V. Lins in litt. 2012). Tourist activities result in river perturbation and have been recorded within known territories and inside national parks (Ibama 2006).

A timeline of the Brazilian Merganser Recovery Project

The start of the Brazilian merganser recovery project

 

The elusive Brazilian Merganser (Mergus octosetaceus) not only ranks among the most endangered of all waterfowl, but rarest of all birds as well. Possibly fewer than 250 birds remain, and some conservationists fear that even this estimate may be optimistic.

 

The river habitat required by the Brazilian Merganser has suffered from staggering deforestation and permanent flooding from dams. The dwindling population of these fish-eating ducks is perhaps most numerous in Brazil's Serra de Canastra National Park, 500 miles northwest of San Paulo. Adding to the birds' plight, a series of forest fires devastated the national park and another area where the merganser was thought to have a stronghold.

 

Mike Lubbock was invited to a workshop in Belo Horizonte, Brazil, in 2000 to help address the dire situation of the Brazilian Merganser. The workshop was organized by Wolf Bartman, of the Dortmund Zoo in Germany. A recovery plan was produced by experts from all three Brazilian Merganser range nations (Argentina, Brazil, and Paraguay), plus Europe and the United States. They collated background information on the status and distribution, life history, and threats faced by the Brazilian Merganser and drew up a basic proposal for conservation action. 

 

Sightings of the merganser have declined over the years; however, while in Brazil, Mike managed to observe several Brazilian Mergansers in the wild on a nearby river. In 2003, Brazilian authorities, researchers and national and international NGOs finalized an Action Plan to save the Brazilian Merganser. The Brazilian Merganser Recovery Team was given "working group status" by the government.

 

Although not yet approved as part of the Action Plan, discussions have recently focused on the need for a Brazilian-based survival breeding program. In April of 2009, Mike Lubbock was again invited to Brazil at the request of Dr. Moacyr Carvalho Dias (Ave é Vida Institute), who operates a significant avian propagation facility in Poços de Caldas, Minas Gerais. The purpose of the visit was to determine if Dr. Moacyr's site would be an appropriate facility for a possible merganser breeding program. The hope is the birds bred at the facility could ultimately be the foundation for a future wild release project, which would help replenish the declining population.

 

New pens had been constructed at Dr. Moacyr's facility, along with an incubator room with new, up-to-date European incubators installed. A brooder room was under construction along with a brand new room with rearing units connected to outside tanks, which were designed especially for diving ducks. The facility upgrades came about through the efforts of Robert Kooy, who has been overseeing Dr. Moacyr's birds - particularly the waterfowl - for the last years. Robert has raised waterfowl all his life and currently manages a very extensive family collection in Holland. Additionally, he received six months of advanced aviculture training from me at Sylvan Heights Waterfowl Breeding Center in North Carolina. Robert Kooy is considered to be one of the top experts in waterfowl propagation.

 

No other facility in Brazil is better equipped to be selected as a study and breeding site for this program, especially since Robert Kooy would be overseeing the husbandry of the mergansers. Despite this species being listed as Critically Endangered, there has been only minimal conservation action taken. We need enough funding to get a survival breeding program underway in Brazil. Global extinction of the Brazilian Merganser appears likely if current trends continue.

 

In 2011, the first collected eggs of Brazilian mergansers hatched in captivity. This was the first time ever, eggs of the species were succesfully incubated artificially.

 

From: Sylvan Heights Bird Park

Above: breeding facilities in Poços de Caldas, Minas Gerais (Brazil), 2010. Photo by Jan Harteman.

Above: incubation room in Poços de Caldas, Minas Gerais (Brazil), 2010. Photo by Jan Harteman.

Above: rearing room in Poços de Caldas, Minas Gerais (Brazil), 2010. Photo by Jan Harteman.

Breeding Brazilian mergansers in aviculture

Above: Brazilian mergansers (four juvenile birds and one adult, at right) in Zooparque Itatiba, 2018. Photo by Jan Harteman.

In 2015, most captive Brazilian mergansers from Poços de Caldas were moved to brand new facilities at Zooparque Itatiba (Sao Paulo State, Brazil). From 2015 on, Zooparque Itatiba is headquarter of the Brazilian Merganser Recovery Project and managing the global ex-situ population. 

 

August 20st 2015 | We just received great news from Robert Kooij: In 2015, 8 ducklings of the Brazilian merganser have hatched at Zooparque Itatiba (Itatiba, SP, Brazil). Eggs from wild birds were collected at several locations (Patrocínio and Jalapao). Currently, Zooparque Itatiba is home to 10 captive Brazilian mergansers. They have been collected from 5 nests in 3 locations. Two more adult birds are currently at the private collection of Criadouro de Aves Poços de Caldas (Poços de Caldas, MG, Brazil), which makes 12 captive birds globally known. All birds are part of the official breeding programma, under supervision of the Brazilian authorities including ICMBio and Terra Brasilis. The sex ratio of these birds is almost 50/50, which gives hope for the future of the species. 

Juvenile white-winged ducks

Above: Brazilian merganser, Zooparque Itatiba, 2018. Photo by Jan Harteman. 

Updates 2018 - 2023

Considering the importance of expanding the ex situ population, it´s crucial that new institutions can integrate in the program and keep the captive mergansers under human care. Therefore, in 2023 two new institutions became members of the Brazilian Merganser Conservation Program and studbook: Prague Zoo (Czech Republic) and Sylvan Heights Bird Park (USA). These institutions are partners of Zooparque Itatiba and have been supporting the program and sponsoring the ex situ activities since the beginning. Both signed the agreements necessary and committed with it, and with that, they agreed that the birds belong to the project.

 

In October 2023, five pairs of Brazilian mergansers were sent to Prague Zoo (Czech Republic). Four pairs are being kept in a back stage breeding facility. One pair is kept on exhibit for education purpose. 

Additional pictures of the Brazilian merganser (ex-situ)

Above: Brazilian mergansers at Zooparque Itatiba, 2018. 

Above: Brazilian merganser at Zooparque Itatiba, 2018. 

Above: Brazilian mergansers at Zooparque Itatiba, 2018. 

Above: Brazilian merganser at Zooparque Itatiba, 2018. 

Above: Brazilian mergansers at Zooparque Itatiba, 2018. 

Above: Brazilian merganser at Zooparque Itatiba, 2018. 

Above: Brazilian merganser at Zooparque Itatiba, 2018. 

Above: Brazilian mergansers Prague Zoo, Czech Republic, 2024. 

Juvenile female (2021)

Above: Brazilian mergansers at Zooparque Itatiba, 2018. 

Above: Brazilian mergansers at Zooparque Itatiba, 2018. 

Above: Brazilian merganser at Zooparque Itatiba, 2018. 

Above: Brazilian merganser at Zooparque Itatiba, 2018. 

Above: Brazilian merganser (aberrant bird) at Zooparque Itatiba.

Above: Brazilian merganser at Zooparque Itatiba, 2018. 

Above: Brazilian merganser at Zooparque Itatiba, 2018. 

Above: Brazilian merganser Prague Zoo, Czech Republic, 2024. 

Above: Brazilian mergansers at Zooparque Itatiba, 2018. Footage by Jan Harteman.

Above: Brazilian mergansers at Poços de Caldas, 2015. Footage by Robert Kooij.

Above: Brazilian mergansers at Poços de Caldas, 2015. Footage by Robert Kooij.

Above: Brazilian mergansers at Prague Zoo, 2024. Footage by Jan Harteman.