Obscure bird of the week: Sao Paulo Antwren

One thing that makes surveying, studying and watching birds so exciting is that new things are always being discovered. Recent discoveries have included the startling find that Yellow Bitterns were breeding in Egypt and the extraordinary migration of the Red-necked Phalarope to the Pacific coast off South America. 

Nothing though can be more exciting than discovering a species unknown to science and this happens with surprising regularity. One of these discoveries occurred in Brazil in 2005 when ecological surveyors cataloguing the area before the proposed construction of a canal chanced upon the Sao Paulo Antwren. This species, which was formally given its scientific name this month, is this week’s “Obscure Bird of the Week”.

The discovery of this attractive marshland dweller follows the discovery of the very similar Parana (or Marsh) Antwren in 1995 in marshes around 400 miles south east of the known sites of the Sao Paulo Antwren. The Sao Paulo Antwren was initially treated as a disconnected race of the Parana Antwren but subtle differences can be observed. The male bird has a much darker black breast and throat and a much lighter crown than its relative. The females are also distinguishable in the field as they have brown upperparts as opposed to the dark greyish tones of the Parana Antwren.

Little is known about the bird’s behaviour and its taxonomy is not entirely satisfactory, with debate as to whether it belongs to the genus Formicivora or Stymphalornis. More crucially, exact population figures are unclear, though clearly small as it is only known from 15 sites. This new species faces many threats including the construction of new dams. The original site of its discovery was flooded for the construction of a reservoir but the birds were saved by a remarkable programme of catching them and releasing them at similar nearby sites. Its precious and limited marshland home is also under serious threat throughout the region due to housing developments and sand extraction.

I observed two males and a female of this species at Biritiba Mirim near Sao Paulo back in 2011 when I was shown it by Rick and Elis Simpson, the people behind Wader Quest (a great cause, check it out here: www.waderquest.org), on the first day of my volunteering at the now defunct Ubatuba Birdwatching Centre. I am privileged to have seen this bird but it saddens me to think that many others may never get the chance. With the grave threats it faces, it is possible that this species may be extinct in under a generation since it was discovered.

-Oliver Simms
Oliver is a 21 year old Classics student in his final year at Durham university. When he is not studying or indeed "birding without birding" on family holidays, he likes to spend his time birding (without pretending he isn't) and hill walking. He is currently secretary of the Durham University Hill Walking Society and Project Co-ordinator of Next Generation Birders

@osimmsbirding

References: http://www.arthurgrosset.com/sabirds/paranaantwren.html

Buzzetti, Belmonte-Lopes, Reinert, Silveira & Bornschein, “A new species of Formicivora Swainson, 1824 (Thamnophilidae) from the state of São Paulo, Brazil”, Revista Brasileira de Ornitologia 21 (2013), 269-291