New records of Picumnus subtilis ( Aves : Picidae ) , Cnipodectes superrufus and Hemitriccus cohnhafti ( Aves : Rhynchocyclidae ) in Acre , Brazil

We report a range extension of the recently described Acre Tody-Tyrant (Hemitriccus cohnhafti) to a site 161 km NE from the type-locality, the third site for this species. The same site is also the fourth Brazilian locality for Finebarred Piculet (Picumnus subtilis). The fourth Brazilian locality for Rufous Twistwing (Cnipodectes superrufus) is also described. All are endemic to southwestern Amazonia and, in Brazil, known only from Acre.

Acre is the western Amazon, a region well-known for its avian diversity (Whittaker and Oren 1999;Whittaker et al. 2002); currently, Acre's bird list includes 668 species (Guilherme 2012; Marques and Guilherme 2014).One of the main reasons for such high species richness is the diversity of habitats resulting from edaphic and soil conditions, and the successional vegetation mosaics influenced by the large rivers draining from the Andes (Kratter 1997).Among the most characteristic habitats in this region are forests dominated by bamboos of the genus Guadua (Poaceae: Bambusoideae), these covering some 180,000 km 2 in Acre, Peru and Bolívia (Nelson 1994).In Acre these forests form a mosaic with other vegetation types and represent 38% of the state's forest cover (Silveira 2005;Guilherme and Santos 2009).
The new records were made in two localities in eastern Acre (Figure 1): Ramal Jarinal (09°54′13″ S, 068°31′45″ W), elevation 200 m -Rio Branco municipality.This is accessed by a road branching from the Transacreana highway northwest of Rio Branco, Acre's capital.The local vegetation is a mosaic of terra firme forest dominated by bamboos and palms, interspaced with pastures and small agricultural plots in varying types.The forests in the area have been cut during the recent past, both for commercial enterprises and for subsistence agriculture.A recent inventory found 266 bird species there (Guilherme and Santos 2009).
Humaita Forest Reserve (09°45′08″ S, 067°40′14″ W), elevation 130 m -Porto Acre municipality.This are belongs to the Brazilian Institute for Colonization and Land Reform (INCRA but was leased to the Acre Federal University) UFAC for research purposes.The reserve has about 3,700 ha, and includes elevations of 130-179 m (Barroso et al. 2011).Humaita is bounded to the east by the Acre River and to the west by the AC-40 road.The main vegetation is open terra firme forest with bamboo (Guadua weberbaueri) and open terra firme forest with palms (Barroso et al. 2011).Despite the area being visited by many ornithologists no bird list has been published for this site.
Observations were made in both sites in August-September 2014 during fieldwork carried by TNM for his master's project and bird-watching outing.Copies of sound recordings are available at Xeno-canto (www.xeno-canto.org)and of photos at Wikiaves (www.wikiaves.com.br)databases.
Fine-barred Piculet, Picumnus subtilis Stager, 1968, was previously considered endemic to southeast Peru in Madre de Dios, Cuzco and Puno (Schulenberg et al. 2007).The first Brazilian records, all in Acre, were of a male collected at Macauã National Forest and now in the collection of the Museu de Zoologia da Universidade de São Paulo, and individuals recorded at the Upper Purus at Santa Cruz Velha (Rego et al. 2009).WikiAves currently has several more recent photo records of this species made in Rio Branco municipality, where TNM has seen it several times.
On 19 August 2014 during a bird-watching outing to Ramal Jarinal, we heard the typical song of Picumnus subtilis, a short sequence of high-pitched notes, at the edge of a bamboo patch by the road.After play-back we located three individuals about 3 m up in a bush, apparently an adult pair together with a juvenile.Answering to the play-back, the trio remained together singing and exploring the branches, allowing several pictures to be taken (Figure 2).
Our record agrees with the suggestions of Rego et al. (2009) and Harvey et al. (2014) that this piculet is associated with lowland bamboo forests.All records in Acre have been made east of the Purus River, coinciding with the portion of the state with largest amount of bamboo (Guilherme and Santos 2009).Including the records of this species from near the urban area of Rio Branco (including the environs of UFAC), some 70 km to the west, our record marks the fourth Brazilian locality for this species.
Acre Tody-Tyrant (Hemitriccus cohnhafti) Zimmer, Whittaker, Sardelli, Guilherme & Aleixo is recently described the type locality 10 km east of Assis Brasil, on the Brazil, Peru and Bolivia border.This site is less than 500 m from the Acre River, which is less than 100 m across at this point.The expected presence of this tody-tyrant in the neighbouring countries (Zimmer et al. 2013) was recently confirmed when it was encountered in Peru at the locality of Portillo, south of the Tahuamanu River (Harvey et al. 2014).
On 19 August 2014, minutes after we recorded the Picumnus subtilis family reported above, we heard the calls of a Hemitriccus cohnhafti at the same road-side patch of bamboo.After playback we got only a brief glimpse of the bird as it  moved away.After exploring several locations further along road, however, we found several other individuals on the same day as well as on a later visit (23 and 24 August).We gathered both photographic (Figure 3) and sound (XC198709) vouchers which confirmed our initial sight records.
The bird in Figure 3 answered the play-back by approaching and calling frequently while moving among bamboo stems 3-4 m above the ground.The understory at all points where we detected tody-tyrants was dominated by bamboo, with few saplings or other species, very similar to the habitat described by Zimmer et al. (2013) and Harvey et al. (2014).At Jarinal H. cohnhafti occurs side by side with H. flammulatus, which is common there (Guilherme and Santos 2009).Our record marks the only third locality for H. cohnhafti and the most distant location we found this species (09°53′68″ S, 068°26′62″ W) extends its range some 161 km to the northeast of the type locality.
Rufous Twistwing, Cnipodectes superrufus Lane, Servat, Valqui & Lambert, 2007, another recently described species, is currently known from 14 localities in Peru (Madre de Dios and Cuzco), Bolívia (Pando) and Brazil (Lane et al. 2007;Tobias et al. 2008;Harvey et al. 2014).In Brazil, it is known from just three localities, all in Acre: Rio Acre Ecological Station, Ramal Jarinal and UFAC's Parque Zoobotânico in Rio Branco (Tobias et al. 2008).It is generally uncommon and hard to detect even in known sites in Acre, although elsewhere it is reportedly common and easy to find when calling (Lane et al. 2007;Tobias et al. 2008).
On 30 August 2014, at Humaita, TNM heard a Cnipodectes superrufus calling at the edge of a bamboo patch beside a small streem.After playback the bird became silent and quietly approached TNM while perching on leafy bamboo branches 1-3 m above the ground.When perched it would frequently raise a wing, as described by Lane et al. (2007) and Tobias et al. (2008).After a few minutes the bird flew away and resumed singing.
On 30 and 31 August and 7 and 14 September 2014 the twistwing was again found at the same location, at whith time it was photographed (Figure 4) and recorded (XC198786).During one of the observations the bird was seen singing and raising one of the wings while foraging.Once it ate a caterpillar caught from a bamboo leaf after sally-striking diagonally upwards.The caterpillar was hit against a branch before being eaten whole.
During 16 days of fieldwork in Humaitá, we used playback to locate individuals, but we were unsuccessful.This record of C. superrufus was made after more than 300 h of fieldwork at that site.Tobias et al. (2008) suggests C. superrufus is one of the rarest and most threatened of the regional bamboo specialist species.Populations seem to be very patchy, and occurrence is unpredictable, with the species being absent from large areas of seemingly adequate habitat (Tobias et al. 2008).

ACKNOWLEDGMENTS
Tomaz Nascimento de Melo thanks CAPES for the research grant and the PPBio -Núcleo Regional Acre for logistical support when carrying fieldwork for his master's at.Rita Souza kindly prepared the maps.

Figure 1 .
Figure 1.Map of localities cited in the text.Type locality refers to the site where Hemitriccus cohnhafti was first discovered and Portillo is the sole Peruvian locality for the species.