Bajo éxito reproductivo de la especie amenazada Sporophila iberaensis en su único sitio reproductivo conocido, los Esteros del Iberá, Argentina

Los pastizales subtropicales se encuentran entre los ecosistemas más amenazados de Sudamérica por su elevada tasa de pérdida de ambiente. Los pastizales del noreste argentino han sido identificados como área prioritaria para la conservación de los capuchinos debido a ser la zona reproductiva principal de estos paseriformes migratorios. Sporophila iberaensis es una especie recientemente descrita en los Esteros del Iberá en Argentina cuya biología es aún muy poco conocida. Esta especie amenazada habita pastizales y el único sitio reproductivo reportado son los humedales del noreste argentino. Para conocer el grado de asociación entre la biología reproductiva de S. iberaensis y los pastizales evaluamos los principales parámetros reproductivos (tamaño de puesta, éxito de eclosión y productividad de volantones), los factores que influyen en la supervivencia de los nidos, la selección del sitio de nido y la fidelidad al sitio de reproducción. Entre los años 2016 y 2018 realizamos búsquedas de nidos y anillamos adultos y pichones en el Parque Nacional Iberá. El periodo reproductivo de S. iberaensis es altamente sincrónico y la probabilidad acumulada de supervivencia de los nidos fue de 0.16. La tasa de supervivencia diaria disminuyó con el avance de la temporada reproductiva y fue menor para los nidos construidos sobre Rhynchospora corymbosa que sobre Paspalum durifolium, los dos sustratos principales de los nidos, siendo principalmente afectada por la depredación y por los vientos fuertes. La población muestra una fidelidad al sitio reproductivo sesgada en los machos y una baja tasa de retorno de las hembras. En contraste con otros capuchinos, cuya biología reproductiva está asociada a pastizales de lomadas arenosas, encontramos que S. iberaensis nidifica exclusivamente en pastizales inundados. Por lo tanto, un manejo eficiente de los pastizales inundables resulta clave para la conservación de esta especie amenazada.Subtropical grasslands are highly susceptible to habitat conversion and number among South America's most threatened ecosystems. The grasslands of northeastern Argentina have been identified as a priority conservation area for threatened capuchino seedeaters because they constitute the main breeding area of these migratory birds. The Iberá Seedeater (Sporophila iberaensis) is a newly described species in the Iberá Wetlands in Argentina whose biology is still poorly understood. The endangered species inhabits grasslands but has only been reported to breed in the Iberá Wetlands ecoregion of northeastern Argentina. To explore the species' association with grassland vegetation, we studied the breeding biology (clutch size, hatching success, and fledgling production) of the Iberá Seedeater and the main parameters that influence nest survival and nest-site selection. We conducted nest searches and banded adults and nestlings in Iberá National Park during the breeding seasons of 2016-2018. The breeding season of the Iberá Seedeater was highly synchronous and the cumulative probability of nest survival was 0.16. The daily nest survival rate decreased as the breeding season advanced, survival was lower for nests supported by Rhynchospora corymbosa than Paspalum durifolium, the two main nest substrates, and the main causes of nest failure were nest predation and strong winds. Additionally, the population exhibited male-biased site fidelity and a low female return rate. In contrast to other capuchinos, whose breeding biology is associated with upland grasslands, the Iberá Seedeater nested exclusively in flooded lowland grasslands on marsh plants. Thus, effective lowland grassland management is key to maintain the vegetation structure required for reproduction in the Iberá Seedeater.Fil: Browne, Melanie. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Turbek, Sheela P.. University of Colorado; Estados UnidosFil: Pasian, Constanza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Di Giacomo, Adrian Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Primera descripcion del nido del capuchino Sporophila iberaensi

The southern capuchino seedeaters constitute a rapid radiation of finch-like birds that inhabit Neotropical grasslands in continental South America. While capuchinos are highly sympatric, the mechanisms allowing them to breed in sympatry, such as patterns of microhabitat use, remain largely unknown. We provide the first nesting account of the Iberá Seedeater (Sporophila iberaensis), a recently discovered capuchino species that breeds exclusively in the Iberá wetlands of northeastern Argentina, and compare its nesting habits to those of other members of the capuchino radiation. From November 2016 to January 2017, we located and monitored 25 Iberá Seedeater nests. The Iberá Seedeater constructs open-cup nests in clumps of grass on the margins of flooded habitat and lays an average of 2 eggs per clutch. Like other capuchino species, females participate in nest construction and incubation, while both sexes provision offspring. Despite similarities in nest architecture, the Iberá Seedeater differs in nesting habitat from the Tawny-bellied Seedeater (S. hypoxantha), its most abundant congener, and other members of the radiation. Many capuchino species, including the Iberá Seedeater, have been classified as endangered or threatened because of habitat loss and trapping for the pet trade. Further information on the breeding biology and habitat requirements of capuchinos will provide insight into the mechanisms that maintain their coexistence in sympatry and inform conservation efforts to protect this enigmatic group.Fil: Turbek, Sheela P.. University of Colorado; Estados UnidosFil: Browne, Melanie. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Pasian, Constanza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Universidad Nacional de Misiones. Instituto de Biología Subtropical; ArgentinaFil: Di Giacomo, Adrian Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

A migratory divide spanning two continents is associated with genomic and ecological divergence

Migratory divides are contact zones between breeding populations with divergent migratory strategies during the nonbreeding season. These locations provide an opportunity to evaluate the role of seasonal migration in the maintenance of reproductive isolation, particularly the relationship between population structure and features associated with distinct migratory strategies. We combine light-level geolocators, genomic sequencing, and stable isotopes to investigate the timing of migration and migratory routes of individuals breeding on either side of a migratory divide coinciding with genomic differentiation across a hybrid zone between barn swallow (Hirundo rustica) subspecies in China. Individuals west of the hybrid zone, with H. r. rustica ancestry, had comparatively enriched stable-carbon and hydrogen isotope values and overwintered in eastern Africa, whereas birds east of the hybrid zone, with H. r. gutturalis ancestry, had depleted isotope values and migrated to southern India. The two subspecies took divergent migratory routes around the high-altitude Karakoram Range and arrived on the breeding grounds over 3 weeks apart. These results indicate that assortative mating by timing of arrival and/or selection against hybrids with intermediate migratory traits may maintain reproductive isolation between the subspecies, and that inhospitable geographic features may have contributed to the diversification of Asian avifauna by influencing migratory patterns

Differential migration and the link between winter latitude, timing of migration, and breeding in a songbird

Patterns of connectivity between breeding and wintering grounds can have important implications for individual fitness and population dynamics. Using light-level geolocators and stable hydrogen isotopes (delta H-2) in feathers, we evaluated differential migration of Savannah sparrows (Passerculus sandwichensis) breeding on Kent Island in the Bay of Fundy, New Brunswick, Canada in relation to sex, age, and body size. Based on geolocators recovered from 38 individuals between 2012 and 2014, the winter distribution was centered in North Carolina (median latitude 34A degrees, range 26A degrees-41A degrees), with males overwintering, on average, approximately 275 km further north than females. Based on analyses of tail feather samples collected from 106 individuals from the same population between 2008 and 2012, males and adults had more negative delta H-2 values than females and juveniles, respectively, providing additional evidence that males wintered north of females and that adults wintered north of juveniles. Winter latitude and delta H-2 values within each sex were not found to be related to body size. From geolocator data, males returned to the breeding grounds, on average, 14 days earlier than females. For males, there was some evidence that arrival date on the breeding grounds was negatively correlated with winter latitude and that individuals which arrived earlier tended to breed earlier. Thus, benefits for males of early arrival on the breeding grounds may have contributed to their wintering farther north than females. Social dominance may also have contributed to age and sex differences in winter latitude, whereby dominant males and adults forced subordinate females and juveniles further south

Concerted variation in melanogenesis genes underlies emergent patterning of plumage in capuchino seedeaters

Coloration traits are central to animal communication; they often govern mate choice, promote reproductive isolation and catalyse speciation. Specific genetic changes can cause variation in coloration, yet far less is known about how overall coloration patterns - which involve combinations of multiple colour patches across the body - can arise and are genomically controlled. We performed genome-wide association analyses to link genomic changes to variation in melanin (eumelanin and pheomelanin) concentration in feathers from different body parts in the capuchino seedeaters, an avian radiation with diverse colour patterns despite remarkably low genetic differentiation across species. Cross-species colour variation in each plumage patch is associated with unique combinations of variants at a few genomic regions, which include mostly non-coding (presumably regulatory) areas close to known pigmentation genes. Genotype-phenotype associations can vary depending on patch colour and are stronger for eumelanin pigmentation, suggesting eumelanin production is tightly regulated. Although some genes are involved in colour variation in multiple patches, in some cases, the SNPs associated with colour changes in different patches segregate spatially. These results suggest that coloration patterning in capuchinos is generated by the modular combination of variants that regulate multiple melanogenesis genes, a mechanism that may have promoted this rapid radiation.Fil: Estalles, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Turbek, Sheela P.. State University of Colorado at Boulder; Estados UnidosFil: Rodríguez Cajarville, María José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Silveira, Luís Fábio. Universidade de Sao Paulo; BrasilFil: Wakamatsu, Kazumasa. Fujita Health University; JapónFil: Ito, Shosuke. Fujita Health University; JapónFil: Lovette, Irby J.. Cornell University; Estados UnidosFil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Lijtmaer, Dario Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Campagna, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Cornell University; Estados Unido

Rapid speciation via the evolution of pre-mating isolation in the Iberá Seedeater

Behavioral isolation can catalyze speciation and permit the slow accumulation of additional reproductive barriers between co-occurring organisms. We illustrate how this process occurs by examining the genomic and behavioral bases of pre-mating isolation between two bird species (Sporophila hypoxantha and the recently discovered S. iberaensis) that belong to the southern capuchino seedeaters, a recent, rapid radiation characterized by variation in male plumage coloration and song. Although these two species co-occur without obvious ecological barriers to reproduction, we document behaviors indicating species recognition by song and plumage traits and strong assortative mating associated with genomic regions underlying male plumage patterning. Plumage differentiation likely originated through the reassembly of standing genetic variation, indicating how novel sexual signals may quickly arise and maintain species boundaries.Fil: Turbek, Sheela P.. University of Colorado; Estados UnidosFil: Browne, Melanie. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Di Giacomo, Adrian Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Kopuchian, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Hochachka, Wesley Michael. Cornell University; Estados UnidosFil: Estalles, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Lijtmaer, Dario Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Silveira, Luís Fábio. Universidade de Sao Paulo; BrasilFil: Lovette, Irby. Cornell University; Estados UnidosFil: Safran, Rebecca J.. University of Colorado; Estados UnidosFil: Taylor, Scott A.. University of Colorado; Estados UnidosFil: Campagna, Leonardo. Cornell University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin