NT
Bare-throated Bellbird Procnias nudicollis



Justification

Justification of Red List Category
This species is suspected to be undergoing a moderately rapid decline owing to ongoing deforestation and trapping. For this reason, it is listed as Near Threatened.

Population justification
It is locally common in Brazil (F. Olmos in litt. 2003) and Paraguay (especially in Canindeyú, San Pedro, and Amambay) (A. Bodrati in litt. 2007), but rare in many sites and rare in Argentina (Bodrati and Cockle 2006). In Argentina, there are suspected to be fewer than 250 mature individuals (MAyDS and Aves Argentinas 2017).

A survey using line transects and acoustic-based distance sampling in primary forest in Pico do Marumbi State Park, Parana, estimated 15 adult males per km2 (95% CI 11.9-18.7; Oliveira 2012). Surveys in Irati National Forest found that the species was 2.6 times more abundant in natural Araucaria forest than in Araucaria plantations (Volpato et al. 2010). Surveys in and around Capão Bonito National Forest found that the species was 2.23 times more abundant in native forest than in planted forest, and 1.25 times more abundant in native forest than in agricultural areas (de Matos et al. 2018).

Based on the area of forest within the mapped range with at least 75% canopy cover in 2010 (c.345,000 km2; Global Forest Watch 2020), a population density of 35.7-56.1 individuals per km2 (Oliveira 2012) and assuming 1% of the habitat is occupied, the population size is tentatively suspected to be in the range 123,165-193,545 individuals, roughly equating to 82,110-129,030 mature individuals and here placed in the band 80,000 - 130,000 mature individuals.

The subpopulation structure is not known.

Trend justification
It appears to have disappeared from some areas of interior semi deciduous Atlantic Forest, and declined in larger remnants, in São Paulo and Paraná states, Brazil (V. Cavarvere in litt. 2020). However, where a forest remnant has been protected and restored in Bahia, the species has recolonised over the past decade and become abundant, expanding its range into areas of secondary forest (K. M. Flesher in litt. 2017, 2018).

Over 17 years from 2002 to 2019, approximately 14% of tree cover with at least 50% canopy cover was lost from within the species's range (Global Forest Watch 2020). From this information, the species's population is inferred to be declining.

A comparison of the results of surveys carried out in 2005-2006 with those carried out 30 years earlier, in a semideciduous forest remnant in the state of São Paulo, found that the species's abundance had declined by 71% across 30 years, which is a rate equivalent to 50% over three generations (Cavarzere et al. 2012).

The species is threatened by trapping as well as by deforestation. It is assumed that trapping may have contributed an additional 10% decline. The species's population size is therefore assumed to have undergone a reduction of up to 24% over the past three generations (17 years), and is assumed to continue to decline at the same rate.

Distribution and population

Procnias nudicollis occurs in a wide area of east Brazil, from Sergipe and Bahia in the north, south to Rio Grande do Sul and inland to south Mato Grosso, north-east Argentina (Misiones, with one record in Corrientes) and east Paraguay (Ridgely and Tudor 1994, Parker et al. 1996, Bertonatti 1997). In Paraguay, the species is primarily found in the northern part of Eastern Paraguay, in Atlantic Forest in Canindeyú and San Pedro departments, with a few birds also recorded in gallery forest in the Cerrado of Concepcion department (R. Clay in litt. 2016). The species is considered extinct from remnant forest patches of north-eastern Brazil north of the São Francisco river, where it was formerly known from the Murici area (F. Olmos in litt. 2003).

Ecology

It prefers primary forest, but may be found in secondary forest where fruit trees are present, and has been heard in abandoned rubber groves (Aleixo and Galetti 1997, K. M. Flesher in litt. 2017, 2018). It appears to be slow to recolonise protected forests, but is able to cross rubber groves to do so, over at least 400m (K. M. Flesher in litt. 2017). It may be an altitudinal migrant, linked to fruit production at different altitudes, with migration patterns differing between age classes (Aleixo and Galetti 1997, Olivera 2012). It is frugivorous, feeding in the canopy on the fruits of plants in the following families: Arecaceae, Myrtaceae, Myrcinaceae, Moraceae, Myristicaceae, Apocynaceae, Sapindaceae, Lauraceae, Leguminosae, Burseraceae, Malpighiaceae, Celastraceae, Elaeocarpaceae, Araliaceae and Liliaceae (Pizo et al. 2002). It breeds from September to February (Oliveiro 2012).

Threats

The population has declined owing to deforestation and heavy trapping pressure for the cage-bird trade, particularly in Brazil (Brooks et al. 1993, Tobias et al. 1993, Ridgely and Tudor 1994, M. Guimarães Diniz in litt. 2003, Kirwan and Green 2011). Trapping pressure may be particularly heavy in southern Bahia, São Paulo and Santa Catarina (F. Olmos in litt. 2003). The Paraguayan population is also coming under increasing pressure from trapping (historically a localised threat), with both males and females readily available in Asunción every year. Agricultural conversion and deforestation for mining and plantation production historically threatened its habitat (Fearnside 1996). Current key threats are urbanisation, industrialisation, agricultural expansion, and road-building (Dinerstein et al. 1995). An analysis of the impact of deforestation in six coastal Brazilian states (from Bahia, south to Parana) found that only around 10% of the species's historical range within those states is remaining (Loiselle et al. 2010). Although there is a Zero Deforestation law in effect in Eastern Paraguay, illegal forest clearance and timber extraction still occurs there (R. Clay in litt. 2016).

Conservation actions

Conservation Actions Underway
The species is listed as Near Threatened in Brazil (MMA 2014) and Endangered in Argentina (MAyDS and Aves Argentinas 2017) and in Paraguay (Ministerio del Ambiente y Desarollo Sostenibile 2019). In Argentina, it has been recorded in Iguazú National Park (Herrera undated) and Reserva de Biosfera Yaboty (Reserva de uso Multiple Guarani and Reserva Natural Cultural Papel Misionero [A. Bodrati and J. I. Areta in litt. 2012), but birds may only occur there on migration. In Paraguay, there are few protected areas with populations of this species (A. Bodrati in litt. 2007), but it occurs in Reserva Natural del Bosque Mbaracayú (R. Clay in litt. 2016). In Brazil, it occurs in Intervales State Park, Pico do Marumbi State Park, Irati National Forest, Capão Bonito National Forest and Guapiaçu Private Ecological Reserve (Volpato et al. 2010, Kirwan and Green 2011, Pimentel and Olmos 2011, Oliveira 2012, de Matos et al. 2018). Around Reserva de Bosque Mbaracayu, Paraguay, the species is featured in outreach campaigns by high school students. Tree planting has taken place to restore forest in an abandoned rubber plantation in Reserva Ecologica Michelin, Itubera, Bahia (K. M. Flesher in litt. 2018).

Conservation and Research Actions Proposed
Conduct further surveys to gain population density estimates and better estimate the population size. Study the species's migration patterns. Evaluate status in Establecimiento San Jorge and neighbouring Iguazú National Park and Urugua-í Provincial Park, Misiones, Argentina, to determine whether the species occurs regularly or only passes through (Bodrati and Cockle 2006). Monitor trapping of the species and evaluate the impact on the species's population size.
Reduce trapping for the cage bird trade through monitoring and awareness campaigns. Protect sites in Paraguay where there are still populations of the species. Protect remaining forest across the species's range. 


Identification

26-28 cm. A striking white forest bird. Male is all white with bare skin around eyes, throat and lower neck, turquoise with inconspicuous black bristles. The smaller female is olive above with blackish crown and sides of head. Throat narrowly streaked white. Pale yellowish underparts coarsely streaked with olive. Similar spp. Male unmistakable in range. Female is larger than the Sharpbill Oxyruncus cristatus which has a conical bill and a characteristic scaly effect on face. Female Bearded Bellbird P. averano is very similar with a less dusky crown. Voice Loud and far carrying series of metallic koínk calls and a loud prróink. Hints The obvious call gives away its presence but is nevertheless hard to locate. Can be found at favoured fruiting trees.

Acknowledgements

Text account compilers
Wheatley, H.

Contributors
Benstead, P., Bodrati, A., Capper, D., Cavarzere, V., Clay, R.P., De Luca, A., Develey, P., Flesher, K., Guimarães Diniz, M., O'Brien, A., Olmos, F., Sharpe, C.J. & Symes, A.


Recommended citation
BirdLife International (2021) Species factsheet: Procnias nudicollis. Downloaded from http://www.birdlife.org on 25/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 25/10/2021.