Salvadori's antwren  (Myrmotherula minor)

Salvadori's antwren is classified as Vulnerable (VU) on the IUCN Red List (1).

Known for its rather acrobatic feeding manoeuvres, Salvadori’s antwren (Myrmotherula minor) is a small bird endemic to south-eastern Brazil (3). The male Salvadori’s antwren is largely grey with the exception of a small black bib and black wings. The male has two lines of white spots on its under-tail coverts and white-fringed tail feathers (4).

Although the female Salvadori’s antwren is also mainly grey, it can be easily distinguished from the male by its olive-brown back, whitish throat and olive-tipped wing feathers (2) (4). The female also has a rusty-orange fringe to the tail feathers and buff underparts (2).

Named after the Italian ornithologist who first described the species in 1864, Salvadori’s antwren has a highly distinctive, complex song (5), comprising a rapid, whistled, two or even three-part song of several sharp, descending syllables (6).

Salvadori’s antwren is the only bird in its genus to have banded under-tail coverts. The band-tailed antwren (Myrmotherula urosticta) is similar in appearance to Salvadori’s antwren, but it has a thick white tip to its tail. The sides of the female white-flanked antwren (Myrmotherula axillaris luctosa) are paler than Salvadori’s antwren and the male white-flanked antwren has a much larger black bib (2).

Salvadori’s antwren is thought to be restricted to the Atlantic forest of south-east Brazil. However, Salvadori’s antwren has occasionally been reported in north-east Peru, although the evidence for this is disputed (3).

Occurring in mature, undisturbed lowland forest, Salvadori’s antwren can also be found in secondary forest, but usually only if re-growth is well established and connected to an area of mature forest. Salvadori’s antwren is almost always found near water, preferring humid areas of forest, rich in mossy tree trunks and bromeliad species (3).

Salvadori’s antwren has been reported to exist at altitudes between sea level and 800 metres, although most recent records are in areas below 300 metres (7).

A sociable bird, Salvadori’s antwren travels in mixed-species flocks with other small insectivores. Within the flock, Salvadori’s antwren is found in a pair or a small family group of up to four members. Pairs quietly call to one another while foraging and are rarely further than three metres apart (6).

Salvadori’s antwren feeds mainly on arthropods and caterpillars of less than 1.5 centimetres in length. It usually forages in foliage between two and eight metres above ground-level. While foraging, the agile Salvadori’s antwren makes acrobatic hops, hitches and flutters and is often seen perching on precarious branches or hanging horizontally or vertically for up to three seconds. When prey is dislodged from the foliage, Salvadori’s antwren will often pursue it in a downwards flutter-chase (6).

Little is known about the breeding biology of Salvadori’s antwren. However, immature Salvadori’s antwrens have been observed with adults in mixed flocks in December and January, indicating that the main breeding season is likely to be between October and January. The breeding period coincides with a great abundance of arthropods, which is thought to help minimise parental foraging efforts and increase chick survival (8).

The already restricted habitat of Salvadori’s antwren is under constant pressure from deforestation, with heavy degradation even in some protected areas (2). As this species is endemic to the Atlantic forest, continued destruction of this habitat is a serious threat (9).

In 2010 the Salvadori’s antwren population was estimated at 2,500 to 10,000 individuals and noted as decreasing (10).

Two biological reserves exist to preserve areas of Atlantic forest in Rio de Janeiro, but other key sites such as Fazenda União remain unprotected. Of the two managed parks in the São Paulo region, one is not adequately protected and the other covers altitudes outside the usual range for Salvadori’s antwren (2).

Conservation of Salvadori’s antwren may be supported by protecting the Fazenda União region, promoting environmental awareness in local communities and monitoring degradation of the remaining Atlantic forest habitat (10).

More information on Salvadori’s antwren:

• BirdLife International - Salvadori’s antwren:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=4662
• Ridgely, R.S. and Tudor, G. (2009) Field Guide to the Songbirds of South America: The Passerines. University of Texas Press, Austin, Texas.

Find out more about bird conservation in Brazil:

• SAVE Brasil:
  http://www.savebrasil.org.br/