Parana antwren (Stymphalornis acutirostris)

Also known as: Marsh antwren
KingdomAnimalia
PhylumChordata
ClassAves
OrderPasseriformes
FamilyThamnophilidae
GenusStymphalornis (1)
SizeLength: 14 cm (2)
Weight10 g (2)

The Parana antwren is classified as Endangered (EN) on the IUCN Red List (1).

Only described as recently as 1995 (2) (3), the Parana antwren (Stymphalornis acutirostris) is a medium-sized, slender, marsh-dwelling bird, found only in a small area of Brazil (4) (5).

The male Parana antwren is typically dark chocolate brown to chestnut-olive on the upperparts and dull lead grey on the underparts (2) (5) (6). The forehead of the male Parana antwren is grey and there is a short, poorly-defined whitish line running from the bill towards the eye (2). There may be some faint white mottling on the chin and cheeks (2) (5). The wings of the male Parana antwren are dusky-grey (5), the flight feathers are edged chestnut-olive (2), and the black wing-coverts have bold white tips (2) (5) (6). The tail is usually blackish and has narrow white tips to the feathers (5) (6).

In contrast to the male, the female Parana antwren is paler brown on the upperparts, and appears generally greyer and more speckled around the face (5) (6). The underparts of the female are whitish and have distinctive coarse black streaks (2) (3) (5) (6). Both the wings and tail of the female Parana antwren are browner than in the male (5).

The song of the Parana antwren is a constant, emphatic series of whistled and repeated nasal ‘piu-píc’ or ‘píc-piu’ notes. Both the male and female Parana antwren also produce ‘nhééé’ calls and soft ‘pic’ contact calls (5).

The Parana antwren is named after the small area of its discovery in coastal Paraná, Brazil (4). It has been found to inhabit several municipalities in Paraná state, as well as several additional municipalities in the neighbouring state of Santa Catarina (5) (6). The Parana antwren is generally restricted to the lowlands between Antonina Bay, Paraná, and the Itapocu River, Santa Catarina (3).

A small population of the Parana antwren may also occur at the Tiete River mouth in São Paulo, although the taxonomic status of this population is uncertain and it may actually represent a separate species (5).

Alternatively known as the marsh antwren, the Parana antwren is almost entirely restricted to marshy habitats (4). It occurs primarily in littoral marshes (2) (4) (5), which are typically dominated by sedges, grasses and other herbaceous (non-woody) vegetation such as bulrush (Scirpus californicus) and cattail (Typha domingensis) (2) (3) (5) (6).

The Parana antwren is also found in marshes alongside rivers, as well as flooded plains and wet fields, the fringes of mangrove swamps and flooded lowland forests (2) (4) (5).

Very little is known about the biology of the Parana antwren (4). It is usually found in pairs in areas of low, dense vegetation (2) (5), where it will forage for prey below heights of around 60 centimetres (5). It is an active species, moving around its marshy habitat by short hops and fluttery flights. These short forays are usually punctuated by short pauses while the Parana antwren scans for prey, which it takes from the leaves and stems of grass and reeds (2). The diet of the Parana antwren is though to consist almost exclusively of arthropods (2) (5).

The Parana antwren is not known to be particularly strong flier, and single flights of more than 25 metres have never been recorded (3).

Constant human pressure is putting the Parana antwren’s habitat at risk, and many areas have already been reduced or destroyed by fires, allotments and landfills. Land acquisition, as well as disturbance and erosion due to boat traffic and sand extraction along river margins, also threatens the Parana antwren and may further reduce its available habitat (5).

Cattle grazing and invasive vegetation, particularly exotic grasses such as Urochloa arrecta and Brachiaria mutica, also pose additional threats to this species’ already vulnerable habitat (3) (5). Rising sea levels are also becoming of increasing concern and could greatly diminish the area of suitable habitat in future (5).

Although proposals for the conservation of the Parana antwren have been put to government agencies in Brazil, no action has yet been taken (5).

Recommended conservation measures for the Parana antwren include protecting key areas of its habitat, as well as carrying out long-term monitoring to determine its population trends (5).

Further studies are needed to find out more about this species’ biology, and to clarify its taxonomic status in São Paulo (5).

Find out more about the Parana antwren: 

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

  1. IUCN Red List (April, 2012)
    http://www.iucnredlist.org/
  2. del Hoyo, J., Elliott, A. and Christie, D. (2003) Handbook of the Birds of the World. Volume 8: Broadbills to Tapaculos. Lynx Edicions, Barcelona.
  3. Reinert, B.L., Bornschein, M.R. and Firkowski, C. (2007) Distribuição, tamanho populacional, hábitat e conservação do bicudinho-do-brejo Stymphalornis acutirostris Bornschein, Reinert e Teixeira, 1995 (Thamnophilidae). Revista Brasileira de Ornitologia, 15(4): 493-519.
  4. Schulenberg, T.S. (Ed.) (2011) Parana antwren (Stymphalornis acutirostris) In: Neotropical Birds Online. Cornell Lab of Ornithology, Ithaca. Available at:
    http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=384531
  5. BirdLife International (April, 2012)
    http://www.birdlife.org/datazone/speciesfactsheet.php?id=9791
  6. Ridgley, R.S. and Tudor, G. (2009) Field Guide to the Songbirds of South America: The Passerines. University of Texas Press, Texas, USA.