8 thoughts on “Black-and-white Monjita (Xolmis dominicanus)”
This grassland specialist lives primarily in native grasslands interspersed with boggy swales and depressions. Within this landscape, it uses the bogs for nesting and roosting but forages mainly in the surrounding drier grasslands, which provide sparse shrubs, rocks, or other low perches for hunting invertebrates. Although it may occasionally use croplands, these are typically small patches embedded within a native grassland matrix. The species’ sensitivity to habitat alteration, particularly grassland loss and fragmentation, underlies its previous classification as threatened.
The proposal to downlist the species from Vulnerable to Near Threatened relies on the assumption that habitat loss across its range does not meet the threshold for a higher threat category. The relevance of the 30% grassland loss documented in Brazil during the first two decades of the 21st century is questioned, with the argument that it may not reflect current conditions or be representative of the species’ entire range. Occasional records in forest edges and agricultural areas are interpreted as signs of broader habitat tolerance. However, this view oversimplifies the species’ ecological requirements and underestimates the concentration of threats in areas that support the largest and most viable subpopulations. Although some individuals may forage in croplands or along forest margins, such use is marginal and typically restricted to areas adjacent to native grasslands. There is no evidence that the species can persist in intensively managed monocultures, forest plantations, or natural forests, which are unlikely to support viable populations.
A particularly problematic aspect of the proposal is the claim that populations may use forested habitats. In practice, individuals in such contexts occupy grassland-forest ecotones and rely exclusively on the grassland component. Likewise, the suggestion that agricultural areas provide alternative habitat overlooks the rapid conversion of native grasslands into industrial row crops and exotic tree plantations, land-use changes that are fundamentally incompatible with the species’ ecological requirements.
Data from eBird and WikiAves suggest the existence of at least eight major subpopulations: (1) Campos Gerais (Paraná), (2) Campos de Palmas and Água Doce (Paraná and Santa Catarina), (3) Planalto das Araucárias and Planalto São Joaquim–Lages (southeastern Santa Catarina and northeastern Rio Grande do Sul), (4) Banhado do Maçarico region (southern coastal Rio Grande do Sul), (5) a broad area from southeastern Rio Grande do Sul into eastern and southern Uruguay, (6) southern Entre Ríos and adjacent southwestern Uruguay, (7) Corrientes and neighboring areas in Paraguay, and (8) coastal Buenos Aires. The largest areas of occurrence, though not necessarily supporting the largest populations, given unknown and likely variable densities, are the Planalto das Araucárias–São Joaquim–Lages, southeastern Rio Grande do Sul into southern Uruguay, and Corrientes. Some individuals undertake seasonal movements, but migratory patterns remain poorly understood, and records outside these core areas may reflect either dispersing individuals or small, local populations. Thus, the range mapped in this proposal is exaggerated, as the species is absent or occurs only locally in central and western Uruguay and western Rio Grande do Sul.
The claim that populations in Corrientes are largely protected also deserves closer examination. Although the Iberá reserve is a major conservation area, it primarily safeguards marshes rather than the open grasslands with linear bogs that the species requires. Most breeding individuals occur outside formally protected areas, in grasslands east and west of the Iberá wetlands that are increasingly threatened by pine and eucalyptus plantations, pine invasion, and extensive fires exacerbated by droughts linked to climate change. While recent satellite imagery suggests that grassland cover in Corrientes has remained relatively stable over the past decade, ongoing threats and the absence of effective protection for grassland-dependent species remain significant concerns.
In Brazil, grassland loss was particularly severe until 2018 and affected key strongholds. Over the past decade, however, it has stabilized in most regions, with the notable exception of southwestern Rio Grande do Sul. In the southeastern Planalto of Santa Catarina, grasslands declined from 258,000 to 246,000 ha, a 4.65% reduction from 2015 to 2024. In the northeastern Planalto das Araucárias of Rio Grande do Sul, the decline was from 495,000 to 474,000 ha (4.24%). In southwestern Rio Grande do Sul, however, the loss was more substantial, from 900,000 to 775,000 ha, a 14% reduction in this same period. It remains unclear how the 30% loss that occurred up to 2018 has impacted Brazilian populations, and stabilization in recent years does not necessarily imply recovery, as population responses may lag behind habitat changes. In Uruguay, grassland loss has also slowed, but threats such as row crop and tree plantation expansion, pine tree invasion and wind farm development may be locally significant. The latter two issues are now affecting the Banhado do Maçarico region, another important stronghold and where grasslands were historically preserved from large-scale conversion.
A past decline of 20–29% over three generations appears reasonable, and there is likely no evidence of a 30% reduction across most of the range, including Brazil, in the past three generations/11 years. I also consider the estimated population size of 11,000–20,000 individuals plausible. However, the reported Extent of Occurrence of 910,000 km² is inflated, as a comparison between the assessment map and occurrence data from eBird and WikiAves makes evident. Given the smaller actual extent, the species’ naturally fragmented distribution, its inability to persist in industrial row crops, forest plantations, or natural forests, and the ongoing threats combined with unknown demographic effects of rapid habitat loss over the past 30 years, I find the justification for downlisting this species to Near Threatened insufficient.
Dias, R. A. (2018). Xolmis dominicanus (Vieillot, 1823). In Livro Vermelho da Fauna Brasileira Ameaçada de Extinção: Volume III – Aves (pp. 548–551). Brasília, DF: ICMBio/MMA.
Based on information from our research group that has been investigating the biology of this species for several years, we consider that it should be retained in the VULNERABLE category since there is insufficient evidence to qualify it as NT.
We leave below a review of the criteria that we quickly made to contribute to this discussion:
Criterion A.
POPULATION DECLINE RATE: >30% over three generations (Vulnerable)
Evidence: Based on longevity data from over 100 banded Alectrurus risora individuals monitored throughout their lives, the species reaches up to 10 years of age. Therefore, a generation length of 20–25 years can be reasonably assumed for Xolmis dominicanus. The population in northeastern Corrientes declined by 50% between 2002 and 2019, according to an unpublished study. In the IBAs of Argentina where all subpopulations and occupied sites of the species were identified, population sizes were estimated in 2008. A recent rapid assessment of their current status shows a decline of at least 33%, with the species disappearing from 5 out of 15 IBAs. In Uruguay’s IBAs identified in 2008, the species is still present, although some sites show apparent declines. The situation in Brazil’s IBAs was not evaluated. Grassland loss and degradation in northeastern Argentina exceeds 30%, due to agricultural expansion, afforestation, livestock intensification (the species does not breed in livestock fields), and recurrent mega-fires. Given that part of the species’ population is located in Entre Ríos and Buenos Aires, where grassland loss and degradation surpass 30%, and this correlates with the disappearance of several populations, the southern population decline trend is even more pronounced. Overall, the species’ presence in IBAs and habitat loss indicate that the population decline rate can be estimated as greater than or equal to 30%.
________________________________________
Criterion B.
Not assessed at this time. However, it is important to note that, unlike Alectrurus risora, which shows colonial or semi-colonial breeding behavior, Xolmis dominicanus has a different reproductive strategy, nesting as isolated pairs with large territories. This results in very low population densities and fluctuating populations.
________________________________________
Criterion C.
POPULATION SIZE: <10,000 individuals (Vulnerable)
Evidence: Fraga (2003) estimated a global population of up to 10,000 individuals, long before large expanses of livestock grasslands were replaced by soybean crops and pine plantations in Argentina, Brazil and Uruguay. Estimates of grassland habitat loss exceed 30%. This estimate is conservative and deterministic, and does not consider potential population fluctuations caused by grassland mega-fires during breeding seasons in the region. Therefore, taking these effects and Fraga’s estimate into account, it is possible that the current global population is below 10,000 individuals.
________________________________________
NATIONAL CONSERVATION STATUS OF THE SPECIES
It is important to note that in the 2015 national Red List assessment of threatened birds of Argentina, conducted by the entire ornithological community using IUCN methodology, the species was classified as EN (Endangered) due to population declines in Buenos Aires and Entre Ríos, and the decreasing trend in Corrientes associated with habitat loss. In the national red lists of Brazil and Uruguay, the species is classified as VU (Vulnerable) in both countries. Considering these assessments were conducted by local experts following IUCN guidelines for national evaluations, at a minimum, the species should retain its global VU status until a new comprehensive global assessment involving local experts is conducted.
Contributors: Alejandro Di Giacomo (AVES ARGENTINAS), Melanie Browne (CONICET), Juan Francisco Cataudela (CONICET), Cecilia Kopuchian (CONICET & AVES ARGENTINAS), Simon Kraemer (CONICET), Florencia Pucheta (CONICET & AVES ARGENTINAS), Jonas Rosoni (CONICET), Adrian Di Giacomo (CONICET & AVES ARGENTINAS).
Geographic Distribution (Misleading)
Brazil: No verified records exist for Xolmis dominicanus in São Paulo; if present, occurrences likely represent vagrants. Silveira & Uezu (2011) confirm the species’ absence.
Paraguay: Historical records (e.g., Contreras, 1995) are unsubstantiated and likely stem from misidentification (e.g., with Xolmis velatus). The species is absent from recent avifaunal checklists and citizen science platforms (e.g., eBird). Targeted surveys in suitable habitats near Argentina (Codesido & Fraga, 2009) yielded no detections. The estimate of 3,000 individuals attributed to Paraguay (Fontana et al., 2013) is a misinterpretation; the original figure referred to Uruguay.
Confirmed Range: Restricted to localized populations in Argentina, Uruguay, and southern Brazil; the species is endemic to southern South America.
Population Size and Structure
The global population comprises 7–8 disjunct subpopulations. Only three to four support >1,000 mature individuals, notably: Corrientes (Argentina), Campos de Cima da Serra (northeastern RS) and southeastern SC (Brazil), and coastal Uruguay. Remaining populations are small (dozens to hundreds of individuals).
Campos de Cima da Serra (RS): Estimated decline >30% between 1999–2010 (pers. comm.).
• Santa Catarina Highlands: Decline >50%, associated with wetland and grassland loss/degradation. The species is categorized as Endangered (EN) in SC (unpublished Red List reassessment) and PR.
Drivers of decline include conversion to agriculture (grain, forestry), non-prescribed burning, and intensive grazing, directly impacting nesting microhabitats. Legal rollbacks (e.g., SC Law 14675/2009 amended by Law 18350/2022) have reduced protection of highland grasslands by redefining protected altitudes (>1500 m), excluding most of the species’ Brazilian range (typically 900–1200 m).
Habitat and Ecology
Obligate grassland species requiring wet fields with Eryngium spp. for nesting/roosting. Foraging occurs in open grassland habitats with minimal shrub cover. The species does not breed in modified environments but may briefly use early-stage forestry plots (<1 m height) as perches. It is absent once canopy closure begins to occur.
Extremely sensitive to disturbance. Nest monitoring (n=10; experienced field team) resulted in 100% nest abandonment, even with minimal observer presence.
Low reproductive plasticity increases vulnerability to disturbance, nest parasitism, and predation.
Migration and Population Connectivity
Migratory behavior remains poorly characterized. Historical and contemporary literature (Gibson 1918; Hudson 1920; Contreras 1995; Fraga 2003; Sick 1987) references migratory movements in Argentina and Brazil, yet empirical data are lacking. Bencke et al. (2024) support partial migration in Brazil; individuals are irregularly observed across different regions and seasons.
In Argentina, movements between the coast and inland wetlands (Pantanal) are documented (Caplonch, 2018). The potential for seasonal interchange among populations in Argentina, Uruguay, and Brazil raises concerns of inflated global population estimates. Research on migratory connectivity is urgently needed.
Legal Protection and Habitat Safeguards
Most Brazilian breeding sites occur outside legally protected areas, predominantly on private lands vulnerable to anthropogenic pressures. Native grasslands—critical habitat—receive minimal protection (<0.5%) (Overbeck et al., 2007).
Presence within protected areas does not ensure effective conservation, especially if habitat quality and size are inadequate for the species’ spatial requirements. The species typically occurs in pairs or small groups, with occasional larger aggregations likely related to dispersal/migration.
In Corrientes (Argentina), key populations persist outside the Iberá Reserve in livestock and forestry-dominated landscapes (J. Rosoni, pers. comm.).
In Brazil, a population decline commensurate with habitat loss—estimated at 31.7% between 2014 and 2025—is projected, corresponding to a reduction of over 30% within three generations (11 years) (Silveira et al., 2023). This projection relies on a generation time of 3.62 years, as estimated by Bird et al. (2020) using generalized models for the Tyrannidae family. However, this figure lacks empirical support from species-specific life history data and appears inconsistent with field observations of X. dominicanus. In the absence of key demographic parameters—such as age at first breeding (F), maximum longevity (L), and annual adult survival (S)—it is advisable to base generation time estimates on phylogenetically or ecologically similar taxa within the Fluvicolinae subfamily. A suitable reference is Alectrurus risora, for which such demographic data are available.
Conclusion and Red List Assessment
The proposed downlisting to Near Threatened (NT) is not supported by current evidence. Key concerns include:
1. High ecological specialization.
2. Documented population declines.
3. Severe habitat loss and fragmentation.
4. Low tolerance to disturbance and reproductive sensitivity.
5. Erroneous data (e.g., inflated population estimates for Paraguay, for example).
6. Underrecognized migratory behavior and subpopulation structure, affecting EOO/AOO calculations.
Recommendation: Retain classification as Vulnerable (VU). Given the ecological sensitivity, limited protection, and major information deficits, a precautionary, conservation-oriented approach is strongly justified.
BENCKE, Glayson A.; DIAS, Rafael A.; FONTANA, Carla Suertegaray. Birds of the Campos Sulinos. South Brazilian grasslands: ecology and conservation of the Campos Sulinos, p. 231-287, 2023.
CAPLLONCH, Patricia. Un panorama de las migraciones de aves en Argentina. El hornero, v. 33, n. 1, p. 01-18, 2018.
CODESIDO, Mariano; FRAGA, Rosendo Manuel. Distributions of threatened grassland passerines of Paraguay, Argentina and Uruguay, with new locality records and notes on their natural history and habitat. Ornitología Neotropical, v. 20, n. 4, p. 585-595, 2009.
Hudson, W. H. 1920. Birds of La Plata. J. M. Dent, London, UK
OVERBECK, Gerhard E. et al. Brazil's neglected biome: the South Brazilian Campos. Perspectives in Plant Ecology, Evolution and Systematics, v. 9, n. 2, p. 101-116, 2007.Hudson
Gibson, E. 1918. Further ornithological notes from the neighbourhood of Cape San Antonio, province of Buenos Aires. Ibis 10: 363–415.
Sick, H. 1987. Ornitologia Brasileira, Rio de janeiro, Nova Fronteira.
SILVEIRA, Luís Fábio; UEZU, Alexandre. Checklist das aves do estado de São Paulo, Brasil. Biota Neotropica, v. 11, p. 83-110, 2011
There are no documented records of the species in Paraguay, and it has not been observed despite fieldwork in recent years in seemingly appropriate habitat in areas adjacent to the northern extent of its range in Argentina. Sight records reported in Contreras (1995) are primarily from the distribution of Xolmis velatus in Paraguay and presumably refer to that species, as does one of two specimens reported by said author (del Castillo and Clay 2004). The other specimen, in BMNH is a historical record from Villarica, a known center of bird trade, collected by a known aviculturalist (so of doubtful origin) (del Castillo and Clay 2004).
Contreras, J. R. (1995) Heteroxolmis dominicana (Vieillot, 1823) en la República del Paraguay (Aves, Tyrannidae). Notulas Faunisticas 76:1-3
del Castillo, H. and Clay, R. P. (2004) Annotated checklist of the birds of Paraguay. Guyra Paraguay: Asunción, Paraguay.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments until 25 April 2025. We will now analyse and interpret the information, and we will post a preliminary decision on this species’ Red List category on this page on 25 April 2025, when discussions will re-open.
We thank all contributors for the information provided in the above comments and via email. All relevant information will be incorporated into the updated species factsheets.
Based on available information, our preliminary proposal for the 2025 Red List would be to list
Black-and-white Monjita as Vulnerable under Criteria A2c+3c+4c. This is based on a revised population reduction exceeding 30% over three generations.
We would like to respond specifically to each criteria discussed and ask for further information to support this assessment.
Criterion A: The calculation of generation lengths for the IUCN Red List should follow the approaches set out in the Red List Guidelines (IUCN 2024). For species that lack sufficient data to calculate a value based on a life-history table, BirdLife follows the methodology by Bird et al. (2020) for calculating generation lengths, which seeks to find the average age of parents of the current cohort. Using this method, a generation length of 3.62 years is determined for this species, hence a three-generation period is 11 years. This is not inconsistent with a species with a longevity of around 10 years due to the interplay of mortality and reproductive success within a cohort.
Initially, the assessment challenged the projected 31.7% habitat loss for Brazil by Silveira et al. (2023), and determined that a reduction >30% was unlikely to have occurred over the entire range on the grounds that habitat loss has slowed in Brazil and that rates are likely slower elsewhere, the presumption that the population in Iberá National Park is secure, and reports that the species can utilise forest and agricultural habitats. R.A. Dias agrees that habitat loss has slowed in Brazil (and Uruguay), but information provided by A.S. Di Giacomo indicate that declines in Argentina may be approaching or exceeding 30% over three generations. Additionally, R.A. Dias provided information indicating that there are significant threats to the population in Iberá National Park and that the original assumption of habitat use was oversimplified. Therefore, a more precautionary approach is justified, and a maximum global reduction of 32% is suspected (in line with the Brazilian National Red List). The species is therefore suspected to be undergoing declines between 20-32% over three generations and is assessed as Vulnerable under Criteria A2c+3c+4c.
However, further information would be beneficial in supporting this assessment. We kindly ask whether the unpublished report referenced by A.S. Di Giacomo for the declines in Argentina can be made available to us, or whether the underlying data and calculations be made available?
Criterion B: Information provided by R.A. Dias, C.S. Fontana, and R. Clay is appreciated, and will be used to inform an updated range map that better reflects verified records. However, the species’ distribution indicates that the EOO/AOO is still large, and it will not meet the thresholds for Vulnerable under Criterion B.
Criterion C: C.S. Fontana suggests that the species occurs in 7-8 subpopulations, of which three to four contain >1,000 mature individuals. This information discounts the species for listing as Vulnerable under Criterion C2 which requires that the largest subpopulation contains <1,000 mature individuals or holds 100% of the population.
Regardless, we would like to clarify information on the population size where possible.
In response to A.S. Di Giacomo: Fraga (2003) appears to only discuss Argentinian populations and to report BirdLife’s assessment in 2000 which stated that there were likely “less than 10,000 individuals”. After this there is the estimate of 10,000 mature individuals for the National Red List for Brazil (Silveira et al. 2023), indicating that a reasonable current value for the global population size must exceed 10,000 mature individuals. Is there any additional information which would support a revision of the global population size to a value lower than <10,000 mature individuals?
In response to C.S. Fontana and R. Clay: Thank you for the clarification that the estimate of 3,000 mature individuals attributed to Paraguay is in fact for Uruguay, and for the notes on the lack of any documented records for Paraguay. We will revise the map to exclude Paraguay from the range.
There is now a period for further comments until the final deadline on 4 May 2025, after which the recommended categorisations will be put forward to IUCN.
The final 2025 Red List categories will be published on the BirdLife and IUCN websites in October 2025, following further checking of information relevant to the assessments by both BirdLife and IUCN.
References:
Bird, J.P., Martin, R., Akçakaya, H.R., Gilroy, J., Burfield, I.J., Garnett, S.T., Symes, A., Taylor, J., Şekercioğlu, Ç.H. and Butchart, S.H. (2020). Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology, 34(5), pp.1252-1261.
Fraga, R.M., 2003. Distribution, natural history and conservation of the Black-and-white Monjita (Heteroxolmis dominicana) in Argentina, a species vulnerable to extinction. Ornitología Neotropical, 14(2), pp.145-156.
Silveira, L.F., Lima, D.M., Dias, F.F., Ubaid, F.K., Bencke, G.A., Repenning, M., Cerqueira, P.V., Dias, R.A., Alquezar, R.D., and Costa, T.V.V. 2023. Heteroxolmis dominicanus (Vieillot, 1823). Available at: https://salve.icmbio.gov.br.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments. We will analyse and interpret the information, and a final decision on this species’ Red List category will be posted on this page on 12 May 2025.
This grassland specialist lives primarily in native grasslands interspersed with boggy swales and depressions. Within this landscape, it uses the bogs for nesting and roosting but forages mainly in the surrounding drier grasslands, which provide sparse shrubs, rocks, or other low perches for hunting invertebrates. Although it may occasionally use croplands, these are typically small patches embedded within a native grassland matrix. The species’ sensitivity to habitat alteration, particularly grassland loss and fragmentation, underlies its previous classification as threatened.
The proposal to downlist the species from Vulnerable to Near Threatened relies on the assumption that habitat loss across its range does not meet the threshold for a higher threat category. The relevance of the 30% grassland loss documented in Brazil during the first two decades of the 21st century is questioned, with the argument that it may not reflect current conditions or be representative of the species’ entire range. Occasional records in forest edges and agricultural areas are interpreted as signs of broader habitat tolerance. However, this view oversimplifies the species’ ecological requirements and underestimates the concentration of threats in areas that support the largest and most viable subpopulations. Although some individuals may forage in croplands or along forest margins, such use is marginal and typically restricted to areas adjacent to native grasslands. There is no evidence that the species can persist in intensively managed monocultures, forest plantations, or natural forests, which are unlikely to support viable populations.
A particularly problematic aspect of the proposal is the claim that populations may use forested habitats. In practice, individuals in such contexts occupy grassland-forest ecotones and rely exclusively on the grassland component. Likewise, the suggestion that agricultural areas provide alternative habitat overlooks the rapid conversion of native grasslands into industrial row crops and exotic tree plantations, land-use changes that are fundamentally incompatible with the species’ ecological requirements.
Data from eBird and WikiAves suggest the existence of at least eight major subpopulations: (1) Campos Gerais (Paraná), (2) Campos de Palmas and Água Doce (Paraná and Santa Catarina), (3) Planalto das Araucárias and Planalto São Joaquim–Lages (southeastern Santa Catarina and northeastern Rio Grande do Sul), (4) Banhado do Maçarico region (southern coastal Rio Grande do Sul), (5) a broad area from southeastern Rio Grande do Sul into eastern and southern Uruguay, (6) southern Entre Ríos and adjacent southwestern Uruguay, (7) Corrientes and neighboring areas in Paraguay, and (8) coastal Buenos Aires. The largest areas of occurrence, though not necessarily supporting the largest populations, given unknown and likely variable densities, are the Planalto das Araucárias–São Joaquim–Lages, southeastern Rio Grande do Sul into southern Uruguay, and Corrientes. Some individuals undertake seasonal movements, but migratory patterns remain poorly understood, and records outside these core areas may reflect either dispersing individuals or small, local populations. Thus, the range mapped in this proposal is exaggerated, as the species is absent or occurs only locally in central and western Uruguay and western Rio Grande do Sul.
The claim that populations in Corrientes are largely protected also deserves closer examination. Although the Iberá reserve is a major conservation area, it primarily safeguards marshes rather than the open grasslands with linear bogs that the species requires. Most breeding individuals occur outside formally protected areas, in grasslands east and west of the Iberá wetlands that are increasingly threatened by pine and eucalyptus plantations, pine invasion, and extensive fires exacerbated by droughts linked to climate change. While recent satellite imagery suggests that grassland cover in Corrientes has remained relatively stable over the past decade, ongoing threats and the absence of effective protection for grassland-dependent species remain significant concerns.
In Brazil, grassland loss was particularly severe until 2018 and affected key strongholds. Over the past decade, however, it has stabilized in most regions, with the notable exception of southwestern Rio Grande do Sul. In the southeastern Planalto of Santa Catarina, grasslands declined from 258,000 to 246,000 ha, a 4.65% reduction from 2015 to 2024. In the northeastern Planalto das Araucárias of Rio Grande do Sul, the decline was from 495,000 to 474,000 ha (4.24%). In southwestern Rio Grande do Sul, however, the loss was more substantial, from 900,000 to 775,000 ha, a 14% reduction in this same period. It remains unclear how the 30% loss that occurred up to 2018 has impacted Brazilian populations, and stabilization in recent years does not necessarily imply recovery, as population responses may lag behind habitat changes. In Uruguay, grassland loss has also slowed, but threats such as row crop and tree plantation expansion, pine tree invasion and wind farm development may be locally significant. The latter two issues are now affecting the Banhado do Maçarico region, another important stronghold and where grasslands were historically preserved from large-scale conversion.
A past decline of 20–29% over three generations appears reasonable, and there is likely no evidence of a 30% reduction across most of the range, including Brazil, in the past three generations/11 years. I also consider the estimated population size of 11,000–20,000 individuals plausible. However, the reported Extent of Occurrence of 910,000 km² is inflated, as a comparison between the assessment map and occurrence data from eBird and WikiAves makes evident. Given the smaller actual extent, the species’ naturally fragmented distribution, its inability to persist in industrial row crops, forest plantations, or natural forests, and the ongoing threats combined with unknown demographic effects of rapid habitat loss over the past 30 years, I find the justification for downlisting this species to Near Threatened insufficient.
References
Dias, R. A. (2018). Xolmis dominicanus (Vieillot, 1823). In Livro Vermelho da Fauna Brasileira Ameaçada de Extinção: Volume III – Aves (pp. 548–551). Brasília, DF: ICMBio/MMA.
MapBiomas Pampa Platform. (2025). Retrieved from https://plataforma.pampa.mapbiomas.org/
MapBiomas Brasil Platform. (2025). Retrieved from https://plataforma.brasil.mapbiomas.org/cobertura?activeBaseMap=9&layersOpacity=100&activeModule=coverage&activeModuleContent=coverage%3Acoverage_main
Based on information from our research group that has been investigating the biology of this species for several years, we consider that it should be retained in the VULNERABLE category since there is insufficient evidence to qualify it as NT.
We leave below a review of the criteria that we quickly made to contribute to this discussion:
Criterion A.
POPULATION DECLINE RATE: >30% over three generations (Vulnerable)
Evidence: Based on longevity data from over 100 banded Alectrurus risora individuals monitored throughout their lives, the species reaches up to 10 years of age. Therefore, a generation length of 20–25 years can be reasonably assumed for Xolmis dominicanus. The population in northeastern Corrientes declined by 50% between 2002 and 2019, according to an unpublished study. In the IBAs of Argentina where all subpopulations and occupied sites of the species were identified, population sizes were estimated in 2008. A recent rapid assessment of their current status shows a decline of at least 33%, with the species disappearing from 5 out of 15 IBAs. In Uruguay’s IBAs identified in 2008, the species is still present, although some sites show apparent declines. The situation in Brazil’s IBAs was not evaluated. Grassland loss and degradation in northeastern Argentina exceeds 30%, due to agricultural expansion, afforestation, livestock intensification (the species does not breed in livestock fields), and recurrent mega-fires. Given that part of the species’ population is located in Entre Ríos and Buenos Aires, where grassland loss and degradation surpass 30%, and this correlates with the disappearance of several populations, the southern population decline trend is even more pronounced. Overall, the species’ presence in IBAs and habitat loss indicate that the population decline rate can be estimated as greater than or equal to 30%.
________________________________________
Criterion B.
Not assessed at this time. However, it is important to note that, unlike Alectrurus risora, which shows colonial or semi-colonial breeding behavior, Xolmis dominicanus has a different reproductive strategy, nesting as isolated pairs with large territories. This results in very low population densities and fluctuating populations.
________________________________________
Criterion C.
POPULATION SIZE: <10,000 individuals (Vulnerable)
Evidence: Fraga (2003) estimated a global population of up to 10,000 individuals, long before large expanses of livestock grasslands were replaced by soybean crops and pine plantations in Argentina, Brazil and Uruguay. Estimates of grassland habitat loss exceed 30%. This estimate is conservative and deterministic, and does not consider potential population fluctuations caused by grassland mega-fires during breeding seasons in the region. Therefore, taking these effects and Fraga’s estimate into account, it is possible that the current global population is below 10,000 individuals.
________________________________________
NATIONAL CONSERVATION STATUS OF THE SPECIES
It is important to note that in the 2015 national Red List assessment of threatened birds of Argentina, conducted by the entire ornithological community using IUCN methodology, the species was classified as EN (Endangered) due to population declines in Buenos Aires and Entre Ríos, and the decreasing trend in Corrientes associated with habitat loss. In the national red lists of Brazil and Uruguay, the species is classified as VU (Vulnerable) in both countries. Considering these assessments were conducted by local experts following IUCN guidelines for national evaluations, at a minimum, the species should retain its global VU status until a new comprehensive global assessment involving local experts is conducted.
Contributors: Alejandro Di Giacomo (AVES ARGENTINAS), Melanie Browne (CONICET), Juan Francisco Cataudela (CONICET), Cecilia Kopuchian (CONICET & AVES ARGENTINAS), Simon Kraemer (CONICET), Florencia Pucheta (CONICET & AVES ARGENTINAS), Jonas Rosoni (CONICET), Adrian Di Giacomo (CONICET & AVES ARGENTINAS).
Geographic Distribution (Misleading)
Brazil: No verified records exist for Xolmis dominicanus in São Paulo; if present, occurrences likely represent vagrants. Silveira & Uezu (2011) confirm the species’ absence.
Paraguay: Historical records (e.g., Contreras, 1995) are unsubstantiated and likely stem from misidentification (e.g., with Xolmis velatus). The species is absent from recent avifaunal checklists and citizen science platforms (e.g., eBird). Targeted surveys in suitable habitats near Argentina (Codesido & Fraga, 2009) yielded no detections. The estimate of 3,000 individuals attributed to Paraguay (Fontana et al., 2013) is a misinterpretation; the original figure referred to Uruguay.
Confirmed Range: Restricted to localized populations in Argentina, Uruguay, and southern Brazil; the species is endemic to southern South America.
Population Size and Structure
The global population comprises 7–8 disjunct subpopulations. Only three to four support >1,000 mature individuals, notably: Corrientes (Argentina), Campos de Cima da Serra (northeastern RS) and southeastern SC (Brazil), and coastal Uruguay. Remaining populations are small (dozens to hundreds of individuals).
Campos de Cima da Serra (RS): Estimated decline >30% between 1999–2010 (pers. comm.).
• Santa Catarina Highlands: Decline >50%, associated with wetland and grassland loss/degradation. The species is categorized as Endangered (EN) in SC (unpublished Red List reassessment) and PR.
Drivers of decline include conversion to agriculture (grain, forestry), non-prescribed burning, and intensive grazing, directly impacting nesting microhabitats. Legal rollbacks (e.g., SC Law 14675/2009 amended by Law 18350/2022) have reduced protection of highland grasslands by redefining protected altitudes (>1500 m), excluding most of the species’ Brazilian range (typically 900–1200 m).
Habitat and Ecology
Obligate grassland species requiring wet fields with Eryngium spp. for nesting/roosting. Foraging occurs in open grassland habitats with minimal shrub cover. The species does not breed in modified environments but may briefly use early-stage forestry plots (<1 m height) as perches. It is absent once canopy closure begins to occur.
Extremely sensitive to disturbance. Nest monitoring (n=10; experienced field team) resulted in 100% nest abandonment, even with minimal observer presence.
Low reproductive plasticity increases vulnerability to disturbance, nest parasitism, and predation.
Migration and Population Connectivity
Migratory behavior remains poorly characterized. Historical and contemporary literature (Gibson 1918; Hudson 1920; Contreras 1995; Fraga 2003; Sick 1987) references migratory movements in Argentina and Brazil, yet empirical data are lacking. Bencke et al. (2024) support partial migration in Brazil; individuals are irregularly observed across different regions and seasons.
In Argentina, movements between the coast and inland wetlands (Pantanal) are documented (Caplonch, 2018). The potential for seasonal interchange among populations in Argentina, Uruguay, and Brazil raises concerns of inflated global population estimates. Research on migratory connectivity is urgently needed.
Legal Protection and Habitat Safeguards
Most Brazilian breeding sites occur outside legally protected areas, predominantly on private lands vulnerable to anthropogenic pressures. Native grasslands—critical habitat—receive minimal protection (<0.5%) (Overbeck et al., 2007).
Presence within protected areas does not ensure effective conservation, especially if habitat quality and size are inadequate for the species’ spatial requirements. The species typically occurs in pairs or small groups, with occasional larger aggregations likely related to dispersal/migration.
In Corrientes (Argentina), key populations persist outside the Iberá Reserve in livestock and forestry-dominated landscapes (J. Rosoni, pers. comm.).
In Brazil, a population decline commensurate with habitat loss—estimated at 31.7% between 2014 and 2025—is projected, corresponding to a reduction of over 30% within three generations (11 years) (Silveira et al., 2023). This projection relies on a generation time of 3.62 years, as estimated by Bird et al. (2020) using generalized models for the Tyrannidae family. However, this figure lacks empirical support from species-specific life history data and appears inconsistent with field observations of X. dominicanus. In the absence of key demographic parameters—such as age at first breeding (F), maximum longevity (L), and annual adult survival (S)—it is advisable to base generation time estimates on phylogenetically or ecologically similar taxa within the Fluvicolinae subfamily. A suitable reference is Alectrurus risora, for which such demographic data are available.
Conclusion and Red List Assessment
The proposed downlisting to Near Threatened (NT) is not supported by current evidence. Key concerns include:
1. High ecological specialization.
2. Documented population declines.
3. Severe habitat loss and fragmentation.
4. Low tolerance to disturbance and reproductive sensitivity.
5. Erroneous data (e.g., inflated population estimates for Paraguay, for example).
6. Underrecognized migratory behavior and subpopulation structure, affecting EOO/AOO calculations.
Recommendation: Retain classification as Vulnerable (VU). Given the ecological sensitivity, limited protection, and major information deficits, a precautionary, conservation-oriented approach is strongly justified.
BENCKE, Glayson A.; DIAS, Rafael A.; FONTANA, Carla Suertegaray. Birds of the Campos Sulinos. South Brazilian grasslands: ecology and conservation of the Campos Sulinos, p. 231-287, 2023.
CAPLLONCH, Patricia. Un panorama de las migraciones de aves en Argentina. El hornero, v. 33, n. 1, p. 01-18, 2018.
CODESIDO, Mariano; FRAGA, Rosendo Manuel. Distributions of threatened grassland passerines of Paraguay, Argentina and Uruguay, with new locality records and notes on their natural history and habitat. Ornitología Neotropical, v. 20, n. 4, p. 585-595, 2009.
Hudson, W. H. 1920. Birds of La Plata. J. M. Dent, London, UK
OVERBECK, Gerhard E. et al. Brazil's neglected biome: the South Brazilian Campos. Perspectives in Plant Ecology, Evolution and Systematics, v. 9, n. 2, p. 101-116, 2007.Hudson
Gibson, E. 1918. Further ornithological notes from the neighbourhood of Cape San Antonio, province of Buenos Aires. Ibis 10: 363–415.
Sick, H. 1987. Ornitologia Brasileira, Rio de janeiro, Nova Fronteira.
SILVEIRA, Luís Fábio; UEZU, Alexandre. Checklist das aves do estado de São Paulo, Brasil. Biota Neotropica, v. 11, p. 83-110, 2011
There are no documented records of the species in Paraguay, and it has not been observed despite fieldwork in recent years in seemingly appropriate habitat in areas adjacent to the northern extent of its range in Argentina. Sight records reported in Contreras (1995) are primarily from the distribution of Xolmis velatus in Paraguay and presumably refer to that species, as does one of two specimens reported by said author (del Castillo and Clay 2004). The other specimen, in BMNH is a historical record from Villarica, a known center of bird trade, collected by a known aviculturalist (so of doubtful origin) (del Castillo and Clay 2004).
Contreras, J. R. (1995) Heteroxolmis dominicana (Vieillot, 1823) en la República del Paraguay (Aves, Tyrannidae). Notulas Faunisticas 76:1-3
del Castillo, H. and Clay, R. P. (2004) Annotated checklist of the birds of Paraguay. Guyra Paraguay: Asunción, Paraguay.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments until 25 April 2025. We will now analyse and interpret the information, and we will post a preliminary decision on this species’ Red List category on this page on 25 April 2025, when discussions will re-open.
Preliminary proposal
We thank all contributors for the information provided in the above comments and via email. All relevant information will be incorporated into the updated species factsheets.
Based on available information, our preliminary proposal for the 2025 Red List would be to list
Black-and-white Monjita as Vulnerable under Criteria A2c+3c+4c. This is based on a revised population reduction exceeding 30% over three generations.
We would like to respond specifically to each criteria discussed and ask for further information to support this assessment.
Criterion A: The calculation of generation lengths for the IUCN Red List should follow the approaches set out in the Red List Guidelines (IUCN 2024). For species that lack sufficient data to calculate a value based on a life-history table, BirdLife follows the methodology by Bird et al. (2020) for calculating generation lengths, which seeks to find the average age of parents of the current cohort. Using this method, a generation length of 3.62 years is determined for this species, hence a three-generation period is 11 years. This is not inconsistent with a species with a longevity of around 10 years due to the interplay of mortality and reproductive success within a cohort.
Initially, the assessment challenged the projected 31.7% habitat loss for Brazil by Silveira et al. (2023), and determined that a reduction >30% was unlikely to have occurred over the entire range on the grounds that habitat loss has slowed in Brazil and that rates are likely slower elsewhere, the presumption that the population in Iberá National Park is secure, and reports that the species can utilise forest and agricultural habitats. R.A. Dias agrees that habitat loss has slowed in Brazil (and Uruguay), but information provided by A.S. Di Giacomo indicate that declines in Argentina may be approaching or exceeding 30% over three generations. Additionally, R.A. Dias provided information indicating that there are significant threats to the population in Iberá National Park and that the original assumption of habitat use was oversimplified. Therefore, a more precautionary approach is justified, and a maximum global reduction of 32% is suspected (in line with the Brazilian National Red List). The species is therefore suspected to be undergoing declines between 20-32% over three generations and is assessed as Vulnerable under Criteria A2c+3c+4c.
However, further information would be beneficial in supporting this assessment. We kindly ask whether the unpublished report referenced by A.S. Di Giacomo for the declines in Argentina can be made available to us, or whether the underlying data and calculations be made available?
Criterion B: Information provided by R.A. Dias, C.S. Fontana, and R. Clay is appreciated, and will be used to inform an updated range map that better reflects verified records. However, the species’ distribution indicates that the EOO/AOO is still large, and it will not meet the thresholds for Vulnerable under Criterion B.
Criterion C: C.S. Fontana suggests that the species occurs in 7-8 subpopulations, of which three to four contain >1,000 mature individuals. This information discounts the species for listing as Vulnerable under Criterion C2 which requires that the largest subpopulation contains <1,000 mature individuals or holds 100% of the population.
Regardless, we would like to clarify information on the population size where possible.
In response to A.S. Di Giacomo: Fraga (2003) appears to only discuss Argentinian populations and to report BirdLife’s assessment in 2000 which stated that there were likely “less than 10,000 individuals”. After this there is the estimate of 10,000 mature individuals for the National Red List for Brazil (Silveira et al. 2023), indicating that a reasonable current value for the global population size must exceed 10,000 mature individuals. Is there any additional information which would support a revision of the global population size to a value lower than <10,000 mature individuals?
In response to C.S. Fontana and R. Clay: Thank you for the clarification that the estimate of 3,000 mature individuals attributed to Paraguay is in fact for Uruguay, and for the notes on the lack of any documented records for Paraguay. We will revise the map to exclude Paraguay from the range.
There is now a period for further comments until the final deadline on 4 May 2025, after which the recommended categorisations will be put forward to IUCN.
The final 2025 Red List categories will be published on the BirdLife and IUCN websites in October 2025, following further checking of information relevant to the assessments by both BirdLife and IUCN.
References:
Bird, J.P., Martin, R., Akçakaya, H.R., Gilroy, J., Burfield, I.J., Garnett, S.T., Symes, A., Taylor, J., Şekercioğlu, Ç.H. and Butchart, S.H. (2020). Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology, 34(5), pp.1252-1261.
Fraga, R.M., 2003. Distribution, natural history and conservation of the Black-and-white Monjita (Heteroxolmis dominicana) in Argentina, a species vulnerable to extinction. Ornitología Neotropical, 14(2), pp.145-156.
Silveira, L.F., Lima, D.M., Dias, F.F., Ubaid, F.K., Bencke, G.A., Repenning, M., Cerqueira, P.V., Dias, R.A., Alquezar, R.D., and Costa, T.V.V. 2023. Heteroxolmis dominicanus (Vieillot, 1823). Available at: https://salve.icmbio.gov.br.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments. We will analyse and interpret the information, and a final decision on this species’ Red List category will be posted on this page on 12 May 2025.