São Paulo Antwren, Biritiba-Mirim, Brazil

One of the least-known taxa in Brazil (and thus probably in the world) is an antwren found only in typha marshes at the head of the Teite River in São Paulo, south-eastern Brazil. Only discovered in February 2005 when an ecological survey was made of an area threatened by a new reservoir (see below for more details), the bird was at first thought to be a form of Parana Antwren Stymphalornis acutirostris – itself only discovered in 1995 and confined to fragmented littoral marshes in Paraná and Santa Catarina several hundred kilometres to the south.

Ongoing studies seem likely to conclude that both taxa are in fact separate species in the genus Formicavora. As Birdlife International already classifies the combined populations of ‘Parana Antwren’ as Endangered, and apparently no-one actually knows with any degree of accuracy how many ‘Marsh’ or ‘São Paulo Antwrens’ there are and where they are within their tiny (and equally fragmented) range the assumption must be that it is extremely rare and either Endangered or Critically Endangered. (The São Paulo Metropolitan area now somehow holds over 20 million people and the demand for land and water resources is crushing and relentless.)

marsh sao paulo antwren

I was shown this pair – almost certainly the only accessible pair of São Paulo Antwren in the world – by professional bird-guide Rick Simpson, of Rick Simpson.com who is based in Ubatuba. He took me to a very dense typha marsh outside the town of Biritiba-Mirim, and after about 45 minutes I managed to get the photos below. There do seem to be very few photographs of the taxon on the net, so hopefully these will be of interest!

The first six photos are of the female (which was slightly more obliging than the male). The habitat here is basically tall, tangled and dense marsh grasses interspered with a few small trees. The antwrens themselves keep low down in the vegetation (between two feet and five feet off the ground when I saw them), are constantly on the move, and though they seemed fairly oblivious to observers it’s incredibly hard to get a clear view of them.


marsh sao paulo antwren


marsh sao paulo antwren


marsh sao paulo antwren


marsh sao paulo antwren


marsh sao paulo antwren


marsh sao paulo antwren
Female Sao Paulo Antwren


marsh sao paulo antwren


marsh sao paulo antwren
Male Sao Paulo Antwren


marsh sao paulo antwren
One that got away – for all those who assume I never panic when I’m faced with a genuine rarity, here’s the moment when I had the male antwren in the open for the first (and last) time and made a complete hash of the shot…To see what is possible when you keep your nerve have a look at a photo on Rick’s blog (scroll down to the bottom).


I was looking for more info on the internet about this intriguing bird – which I knew virtually nothing about before Rick took me to see it – and discovered the following on the superb, encyclopeadic website of Arthur Grosset at http://www.arthurgrosset.com/sabirds/paranaantwren.html


The discovery of this new population / new species took place in February 2005. The press release from the University of São Paulo is here [in Portugese].

My translation into English of this press release is as follows:

  • “The São Paulo version of the Marsh Antbird lived undisturbed in the green belt of the city of São Paulo until, in February 2005, it was identified as a new species of the genus Stymphalornis. From that moment on, it didn’t have a minute’s peace. The reason was that the habitat of the only population known at that time was to be flooded for the construction of the Paraitinga reservoir, creating a great danger for these creatures.

    Immediately the discoverer of the bird, the biologist, Luís Fábio Silveira of the University of São Paulo, together with his team, did everything possible to capture as many individuals as they could and release them in areas with similar vegetation, typha (cattails) marshland. “It is the first time in South America that this procedure, called re-location, has been used for insect-eating passeriforms”, explained the scientist.

    Since there is almost no literature on it, the procedure required special care. “We will monitor all the transferred populations for a year to ensure that they have adapted well to their new habitats.” Silveira kept both IBAMA and the São Paulo Water and Electricity Department informed and they both followed and supported the project.

    In total 72 individuals were captured (35 males and 37 females), all transferred to 12 nearby localities with similar ecosystems, giving priority to protected areas. Silveira states that the approach, although a bit drastic, had to be taken because some characteristics of the species indicated that its population was very small. “It is restricted to a habitat that is not very common in the region.”

    In parallel, another population of the species was located by the biologist Dante Buzetti in the region between Mogi das Cruzes and Arujá, near to the locality where it was first discovered. However, since the area did not present immediate risks, the creatures did not need to be relocated.

    Silveira is now working on the formal description of the new species so that it can be formally recognised by the scientific community. Since it has not yet been described scientifically, it does not have a specific scientific name receiving in the meantime the denomination Stymphalornis sp. nov.. Initially it was thought to be the species S. acutirostris, known as Marsh Antwren (or Parana Antwren) endemic to the coast of Paraná and Santa Catarina.

    With precautions for the preservation of the birds taken it is hoped that the re-location of them will be successful and that the project will provide valuable information for future conservation programmes. The discovery of the birds was announced officially on 5th May 2005 by IBAMA who intend to include it in its list of endangered species.”

Copyright Arthur Grosset http://www.arthurgrosset.com


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About the author

Passionate about animal welfare and conservation, veggie and dairy-free, I live in the Wiltshire (UK) countryside. I co-founded Birders Against Wildlife Crime and Birds Korea. Trustee of the League against Cruel Sports On Twitter @charliemoores

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