Nidificación del Chinchero Escamado (Lepidocolaptes falcinellus)

We provide the first description of the nest of the Scalloped Woodcreeper (Lepidocolaptes falcinellus), its clutch size, nestlings, and nesting behavior from prospecting to fledging, based on 102 h of observation at a nest in the subtropical Atlantic forest at Parque Provincial Cruce Caballero, province of Misiones, Argentina. The nest was in a long vertical crack, 2.5 m high in the trunk of a cedro (Cedrela fissilis). The two adults filled the bottom of the cavity with bark flakes to a height of 11 cm. They took turns incubating the three eggs with 100% attentiveness for 15 to 16 days, and fed the two nestlings a diet of arthropods, especially caterpillars. After the male died, the female raised the nestlings alone and they fledged two days apart, 18 and 19 days after hatching. The Scalloped Woodcreepers were observed on four occasions defending their nest against potential predators and cavity competitors (White-throated Woodcreeper, Xiphocolaptes albicollis; Yellow-fronted Woodpecker, Melanerpes flavifrons; Olivaceous Woodcreeper, Sittasomus griseicapillus). Our observations of nest construction, incubation period, nestling development, nestling period, and parental behavior for Scalloped Woodcreepers were similar to published observations for Streak-headed Woodcreepers (Lepidocolaptes souleyetti) and Spot-crowned Woodcreepers (L. affinis) of tropical Central America; however, Scalloped Woodcreepers had longer bouts on the nest and higher nest-attentiveness during incubation, and in these characteristics were similar to Planalto Woodcreepers (Dendrocolaptes platyrostris) that breed at the same site in northeastern Argentina.We provide the first description of the nest of the Scalloped Woodcreeper (Lepidocolaptes falcinellus), its clutch size, nestlings, and nesting behavior from prospecting to fledging, based on 102 h of observation at a nest in the subtropical Atlantic forest at Parque Provincial Cruce Caballero, province of Misiones, Argentina. The nest was in a long vertical crack, 2.5 m high in the trunk of a cedro (Cedrela fissilis). The two adults filled the bottom of the cavity with bark flakes to a height of 11 cm. They took turns incubating the three eggs with 100% attentiveness for 15–16 days, and fed the two nestlings a diet of arthropods, especially caterpillars. After the male died, the female raised the nestlings alone and they fledged two days apart, 18 and 19 days after hatching. The Scalloped Woodcreepers were observed on four occasions defending their nest against potential predators and cavity competitors (White-throated Woodcreeper, Xiphocolaptes albicollis; Yellow-fronted Woodpecker, Melanerpes flavifrons; Olivaceous Woodcreeper, Sittasomus griseicapillus). Our observations of nest construction, incubation period, nestling development, nestling period, and parental behavior for Scalloped Woodcreepers were similar to published observations for Streak-headed Woodcreepers (Lepidocolaptes souleyetti) and Spot-crowned Woodcreepers (L. affinis) of tropical Central America; however, Scalloped Woodcreepers had longer bouts on the nest and higher nest-attentiveness during incubation, and in these characteristics were similar to Planalto Woodcreepers (Dendrocolaptes platyrostris) that breed at the same site in northeastern Argentina.Fil: Bodrati, Alejandro. Proyecto Selva de Pino Paraná; Argentina. Fundación de Historia Natural Félix de Azara; Argentina. Grupo FALCO; ArgentinaFil: Cockle, Kristina Louise. Fundación de Historia Natural Félix de Azara; Argentina. Proyecto Selva de Pino Paraná; Argentina. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina. University of British Columbia; Canad

Nest niche overlap among the endangered Vinaceous-breasted Parrot (Amazona vinacea) and sympatric cavity-using birds, mammals, and social insects in the subtropical Atlantic Forest, Argentina

Many forest bird species require tree cavities for nesting, and share this resource with a diverse community of animals. When cavities are limited, niche overlap can result in interspecific competition, with negative consequences for threatened populations. Vinaceous-breasted Parrots (Amazona vinacea) are endangered cavity nesters endemic to the subtropical Atlantic Forest, where cavities are scarce. We examined nest niche overlap among Vinaceous-breasted Parrots and 9 potential competitors (birds and mammals >140 g, and social insects) in Argentina, considering (1) timing of breeding, (2) characteristics of cavities (depth, entrance diameter, height), trees (diameter at breast height DBH, species, condition), and habitat (surrounding land use, distance to edge), and (3) interspecific cavity reuse. During 10 breeding seasons we studied nests and roosts, measured their characteristics, and monitored cavities to detect reuse. We used multinomial logistic regression to determine whether the 6 most abundant taxa differed in nest and roost site characteristics. Timing of breeding overlapped for all bird species except the White-eyed Parakeet (Psittacara leucophthalmus). No combination of cavity, tree, and habitat characteristics predicted the taxa that utilized cavities. Moreover, 8 of the 10 taxa reused cavities interspecifically. The high level of overlap in realized nest niche, combined with previous evidence that cavities could limit bird density in our study area, suggest the possibility of interspecific competition for cavities among multiple taxa. Although models did not perform well at classifying cavities by taxon, some characteristics of cavities, trees, and habitat were selected more by Vinaceous-breasted Parrots than by other taxa, and we recommend targeting conservation efforts toward cavities and trees with these characteristics (7-40 cm entrance diameter, >10 m high, DBH >55 cm). We found 62% of Vinaceous-breasted Parrot nests on farms (vs. ≤50% for other taxa), highlighting the importance of working with local farmers to conserve cavities in anthropogenic habitats as well as in protected areas.Fil: Bonaparte, Eugenia Bianca. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Cockle, Kristina Louise. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentina. University of British Columbia; Canad

Biología reproductiva y distribución del Atajacaminos Oscuro (Antrostomus sericocaudatus sericocaudatus) en Misiones, Argentina

El Atajacaminos Oscuro (Antrostomus sericocaudatus) fue tradicionalmente considerado raro, poco conocido, y posiblemente amenazado. Se conocen dos subespecies: A. s. mengeli en Amazonia y A. s. sericocaudatus en la Selva Atlántica ‐ un hotspot de biodiversidad en rápida desaparición en el sudeste de Brasil, este de Paraguay y la provincia de Misiones en Argentina. Las subespecies difieren en vocalizaciones y morfología pero la biología reproductiva ha sido estudiada sólo para A. s. mengeli. Encontramos a A. s. sericocaudatus en todos los remanentes de Selva Atlántica en Misiones, y estudiamos 10 nidos. Durante el despliegue el macho cantó incesantemente en una rama alta cerca o sobre el lugar del futuro nido; cuando la hembra llego a otra rama, el macho redobló el ritmo del canto, voló hacia la hembra (que emitió ladridos suaves), dejó caer sus alas, puso la cola en forma de abanico y montó a la hembra mientras emitía un “croar” bajo. Antrostomus s. sericocaudatus puso 2 huevos de color blanco inmaculado, en contraste con A. s. mengeli y la mayoría de las otras especies del genero Antrostomus, que ponen huevos con marcas. El período de incubación fue de 19 días, y las crías estaban cubiertas por un denso plumón natal color marrón rosado (vs. “dorado” en A. s. mengeli). Durante las horas diurnas la incubación de los huevos y pichones estuvo principalmente a cargo de la hembra, mientras que el macho fue encontrado incubando una vez durante el día y otra por la noche. Ambos padres realizaron despliegues de distracción desde la incubación hasta que los pichones tenían 18–19 días de edad. Considerando el rango restringido y la dependencia a la Selva Atlántica de A. s. sericocaudatus y las diferencias con A. s. mengeli, es clave estudiar el tamaño y trayectoria de la población, y la tolerancia a la fragmentación de la selva, con el objetivo de determinar su estado de conservación global.The Silky‐tailed Nightjar (Antrostomus sericocaudatus) is traditionally considered rare, poorly known, and possibly threatened. It comprises two subspecies: A. s. mengeli in the Amazon basin and A. s. sericocaudatus in the Atlantic Forest – a rapidly disappearing biodiversity hotspot in southeastern Brazil, eastern Paraguay, and the province of Misiones in Argentina. The subspecies differ in vocalizations and morphology, but reproductive biology has been studied only for A. s. mengeli. We found A. s. sericocaudatus throughout remaining Atlantic Forest in Misiones, and studied 10 nests. During courtship, the male sang incessantly from a high branch above the future nest site; when the female landed on another branch, he doubled the pace of his song, flew to the female (who emitted soft barks), dropped his wings, fanned his tail, and mounted the female while emitting a low croak. Antrostomus s. sericocaudatus laid two immaculate white eggs, in contrast to A. s. mengeli and most other Antrostomus, which lay eggs with markings. The incubation period was 19 days, and hatchlings were covered in dense pinkish‐brown down (vs. “golden” in A. s. mengeli). During the day, incubation and brooding were mostly performed by the female, although the male was found incubating once during the day and brooding once at night. Both parents performed distraction displays from incubation until the chicks were 18–19 days old. Considering the restricted range of A. s. sericocaudatus, its dependence on remaining Atlantic Forest, and its differences with A. s. mengeli, it is important to study its population size, population trajectory, and tolerance of forest fragmentation, in order to determine its global conservation status.Fil: Bodrati, Alejandro. Proyecto Selva de Pino Paraná; Argentina. Grupo FALCO; ArgentinaFil: Cockle, Kristina Louise. Proyecto Selva de Pino Paraná; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentin

NEST PREDATION AND INTERSPECIFIC NESTING ASSOCIATIONS INVOLVING PLUMBEOUS KITE (ICTINIA PLUMBEA) AND BECARDS (PACHYRAMPHUS SPP.)

Abstract ∙ Interspecific nesting associations are among several strategies employed by birds to reduce the risk of nest predation. Plumbeous Kites (Ictinia plumbea) aggressively defend their nest sites from potential predators, and participate in a little‐studied nesting association with various species of becards (Pachyramphus spp.). Here, we describe nesting associations involving Ictinia plumbea, other raptors, wasps, and becards, based on field observations from 1997 to 2016 in two ecoregions of Argentina, the Atlantic Forest and the Humid Chaco. We found 48% of Ictinia plumbea nests in close proximity to one or more becard nests. Kite nests were already active when becards began building. Green‐backed Becards (Pachyramphus viridis) were the most frequent associate, nesting 30–150 cm from active kite nests and sometimes appropriating their nest material. When potential predators came near their nests, becards appeared unable to drive them off, but their warning calls alerted the kites, which drove 13 species of potential nest predators away from kite‐becard nesting associations. Two kite nests – both unaccompanied by becards – were confirmed to have failed. At one, a Red‐breasted Toucan (Ramphastos dicolorus) captured the young kite nestling during a brief absence of both parents. We propose that (1) becards select nest sites near kites and benefit from the kites’ aggressive nest defense, and (2) kites tolerate becards, possibly gaining a small advantage from their warning calls. We also found becards nesting beside five other species of raptors, and wasps. Network analysis revealed a higher diversity of protective nesting associations in the Chaco than in the Atlantic Forest, but Ictinia plumbea and wasps were the most frequent nest associates of becards in both systems. Quantitative studies of nest‐site selection and nest survival in becards and kites are needed to reveal the behavioral mechanisms and fitness costs/benefits of this widespread interspecific nest association. Resumen ∙ Predación de nidos y asociaciones interespecíficas de nidos involucrando Milano Plomizo (Ictinia plumbea) y anambés (Pachyramphus spp.) Las interacciones interespecíficas de nidos se cuentan entre varias estrategias que emplean las aves para reducir el riesgo de la depredación de nidos. Los Milanos Plomizos (Ictinia plumbea) protegen agresivamente sus nidos de posibles predadores y participan en una asociación poco estudiada con varias especies de anambés (Pachyramphus spp.). Aquí, describimos asociaciones de protección de nidos que involucran Ictinia plumbea, otras rapaces, avispas y anambés en base a observaciones de campo entre 1997 y 2016 en dos ecoregiones de la Argentina, la Selva Atlántica y el Chaco Húmedo. El 48% de los nidos de Ictinia plumbea se encontraban muy cerca de uno o más nidos de anambé. Los nidos del milano ya estaban activos cuando los anambés empezaron a construir. El Anambé Verdoso (Pachyramphus viridis) fue el socio más frecuente, anidando a 30–150 cm de nidos activos del milano, y a veces apropiándose del material de su nido. Cuando se acercaba un potencial predador, los anambés parecían incapaces de alejarlo, pero sus llamadas alertaron a los milanos, que alejaron a 13 especies de posibles predadores de las asociaciones de nidos milano‐anambé. Dos nidos de milano – ambos sin acompañamiento de un nido de anambé – se confirmaron como fracasados. En uno, un Tucán de Pico Verde (Ramphastos dicolorus) capturó el pichón de milano recién nacido, durante una breve ausencia de ambos padres. Proponemos que (1) los anambés seleccionan sitios para anidar al lado de los milanos y se benefician por la defensa agresiva de estos, y (2) los milanos toleran a los anambés, posiblemente obteniendo una ventaja por sus llamadas de alerta. Además, encontramos anambés anidando junto a otras cinco especies de rapaces, y avispas. Análisis de redes reveló una mayor diversidad de asociaciones de protección de nidos en el Chaco que en la Selva Atlántica, pero Ictinia plumbea y avispas fueron los socios más frecuentes de los anambés en ambos sistemas. Se necesitan estudios cuantitativos de selección de sitios para anidar y supervivencia de nidos en anambés y milanos para revelar los mecanismos comportamentales, así como también los costos y beneficios en cuanto al éxito reproductivo, de esta asociación interespecífica de nidos.

Specialization on bamboo by Neotropical birds

Ornithologists have long marveled at the many species of neotropical forest birds found in close association with woody bamboos (Poaceae: Bambuseae). Over 400 species of woody bamboos occur in the neotropics, a total second only to southeast Asia, which has nearly 1000 species (Bystriakova et al. 2003, 2004). Woody bamboos may grow in the open with a compact shrubby aspect, clamber up trees into the forest canopy, stand erect and self-supported up to 30 m tall, arch over and extend outward, or form dense tangles that carpet the ground, providing a diverse array of microhabitats (McClure 1966, Judziewicz et al. 1999). Their clonal reproduction allows many of them to colonize disturbed areas quickly, forming stands large enough to hold one or more territories of specialist birds (Kratter 1997, Judziewicz et al. 1999, Gagnon and Platt 2008). The synchronous seed production of many bamboos provides abundant and nutritious food for granivores, while bamboos’ fast growth, often hollow stems, and dense tangled habit support diverse arthropod communities that provide food for insectivores (Janzen 1976, Reid et al. 2004, Lebbin 2007). However, specialization by birds on woody bamboos is hindered by dramatic changes in resource availability over time and space. Most neotropical woody bamboos grow vegetatively for 30–40 years, then flower synchronously over large areas and die (Judziewicz et al. 1999). It has long been a mystery how so many species of neotropical birds specialize on such a fluctuating resource, and, more recently, concerns have been raised about how to conserve these species and their interaction relationships in the face of widespread deforestation.Fil: Cockle, Kristina Louise. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Bio y Geociencias del Noroeste Argentino; Argentina. Universidad del Estado de Luisiana. Facultad de Recursos Naturales Renovables; Estados UnidosFil: Areta, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Bio y Geociencias del Noroeste Argentino; Argentin

Comparison of nesting ecology of three co-existing Atlantic Forest woodpeckers reveals narrow specialization in the Helmeted Woodpecker Celeus galeatus

The Atlantic Forest in southeastern South America is a biodiversity hotspot with high species richness and high forest loss. Three large to medium-sized woodpecker species (Robust Woodpecker Campephilus robustus, Lineated Woodpecker Dryocopus lineatus, and the globally threatened Helmeted Woodpecker Celeus galeatus) coexist in the south of the ecoregion, and show remarkable convergence in plumage patterns and colouration, possibly driven by interspecific interactions. We assessed differentiation in nest tree species, nest substrates, and timing of breeding and evaluated whether nesting ecology may be a factor explaining an association with mature forests in the Helmeted Woodpecker. Robust and Lineated Woodpeckers excavated cavities in nine and eight nest tree species, respectively, whereas Helmeted Woodpeckers specialized narrowly on laurel trees (88% of nest cavities in two species in genus Nectandra of 52 ± 14 cm DBH). Helmeted Woodpecker is further distinguished by a more frequent use of living, partially decayed trees and by more frequent re-use of nest cavities. When nesting in selectively logged forest (vs. old-growth), Robust and Lineated Woodpeckers used trees with smaller DBH and Robust Woodpeckers excavated lower in trees. Helmeted Woodpeckers selected nest trees with similar dimensions in both environments, indicating lesser flexibility. Helmeted Woodpeckers bred 20-23 days later in the year than Lineated and Robust Woodpeckers, potentially allowing them to avoid nesting near the two larger species. The narrow specialization of Helmeted Woodpecker on nesting in Nectandra trees of large sizes at the onset of decay is a possible factor in making it sensitive to selective logging effects. To stop declines of Helmeted Woodpecker we recommend (1) sparing large trees from selective logging (including Nectandra and tree species used for roosting), and (2) restoring more forested areas to mature forest conditions.Fil: Lammertink, J. Martjan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Fernández, Juan Manuel. Universidad Nacional del Nordeste; Argentina. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; ArgentinaFil: Cockle, Kristina Louise. University of British Columbia; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentin

Nidificación e historia natural del Tangará Alcalde (Euphonia pectoralis) en Misiones, Argentina, y comparación con otras especies del género

The genus Euphonia includes 28 species that present high levels of specialization on a frugivorous diet, with emphasis on the consumption of mistletoes of the order Santalales. For the Chestnut-bellied Euphonia (Euphonia pectoralis), endemic to the Atlantic Forest of South America, nests and eggs have been described, but other aspects of natural history and reproductive biology are unknown. Here we report observations on foraging and ten reproductive events in eight nests between 2003 and 2018 in Misiones, Argentina. We observed a primarily frugivorous diet in adults and nestlings, although adults occasionally consumed insects when they foraged in mixed species flocks. In contrast to other species of Euphonia, we observed low frequencies of consumption of Santalales fruits. Nests were globular structures of plant material, supported on epiphytic plants, tree trunks, tree ferns, or thin branches 0.93–5.30 m above the ground. Clutch size was 2–3 eggs (n = 6), smaller than for species of Euphonia inhabiting tropical regions, supporting the idea that this genus departs from the general pattern in birds, in which clutch size increases with latitude. The incubation period lasted 16 days and the nestlings fledged when 17–21 days old (n = 2). Both parents participated in nest construction but only the female incubated, brooded, and took care of nest hygiene, ingesting the gelatinous fecal mass directly from the cloaca of her offspring. We observed the male (once) and the female (eight times) feeding the nestlings with regurgitated fruit. Future studies on nesting in the genus Euphonia could help to understand evolution of nesting behaviors in the family, resolve its complex phylogenetic situation, and test hypotheses about the factors influencing clutch size in birds.El género Euphonia incluye 28 especies que presentan una alta especialización a la dieta frugívora, con énfasis en el consumo de ligas del orden Santalales. Para el Tangará Alcalde (Euphonia pectoralis), endémico de la selva Atlántica de Sudamérica, se han descripto nidos y huevos, pero se desconocen otros aspectos de la historia natural y biología reproductiva. Aquí reportamos observaciones de forrajeo y diez eventos de reproducción en ocho nidos entre 2003 y 2018 en Misiones, Argentina. Observamos una dieta mayormente frugívora en adultos y pichones, aunque adultos ocasionalmente consumieron insectos cuando forrajearon en bandadas mixtas. A diferencia de otras especies de Euphonia, observamos escasa frecuencia de consumo de frutos de Santalales. Los nidos eran estructuras globulares de material vegetal, apoyados sobre plantas epífitas, troncos de árboles, helechos arborescentes o ramas finas a unos 0.93–5.30 m del suelo. El tamaño de puesta fue de 2–3 huevos (n = 6), menor a las especies de Euphonia que habitan zonas tropicales, apoyando la idea de que este género representa una excepción al patrón general en las aves, donde el tamaño de puesta aumenta con la latitud. El período de incubación duró 16 días y los pichones abandonaron el nido a los 17–21 días (n = 2). Ambos padres participaron en la construcción de los nidos pero solo la hembra incubó, empolló y se ocupó de la higiene, tomando la masa gelatinosa fecal directamente de la cloaca de sus pichones. Observamos una vez al macho y ocho veces a la hembra alimentando a los pichones con regurgitaciones de frutas. Futuros estudios sobre la nidificación del género Euphonia podrían ayudar a determinar tendencias evolutivas dentro del género, resolver su situación filogenética compleja, y testear hipótesis sobre los factores que influyen en el tamaño de puesta de las aves.Fil: Di Sallo, Facundo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; ArgentinaFil: Bodrati, Alejandro. Proyecto Selva de Pino Paraná; ArgentinaFil: Cockle, Kristina Louise. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. Proyecto Selva de Pino Paraná; Argentina. University of British Columbia; Canad

VOCALIZACIONES, SONIDOS MECÁNICOS Y DESPLIEGUES DEL ATAJACAMINOS ALA NEGRA (ELEOTHREPTUS ANOMALUS) EN ARGENTINA

Resumen ∙ El Atajacaminos Ala Negra (Eleothreptus anomalus) habita pastizales húmedos del Sur de Sudamérica y se lo considera “cercano a la amenaza” debido a su baja abundancia y pérdida de hábitat. El macho se caracteriza por alas extrañas, con forma de hacha, con las primarias curvadas hacia atrás y las secundarias sensiblemente más cortas, posiblemente una adaptación para producir sonidos mecánicos. Se especula que su sistema de apareamiento podría ser tipo lek, pero existe poca evidencia, no se han descripto sus despliegues y existe confusión sobre el origen y significado de sus sonidos. Aquí presentamos información sobre los sonidos y despliegues de E. anomalus en base a grabaciones y observaciones realizadas con una población marcada en Reserva Natural Rincón de Santa María, Corrientes, Argentina (RNRSM; 2009–2018) y observaciones adicionales en Barra Concepción, Misiones, Argentina (2003–2004). En los últimos 9 años observamos concentraciones de hasta 15 machos realizando despliegues en dos tramos de caminos elevados y poco transitados de la RNRSM, que consideramos arenas de despliegue, reforzando la idea de que se trata de un sistema lek. Encontramos cinco tipos de sonidos. 1) Hembras y machos realizan llamadas de contacto (series de "tik" o "tzk"; dos variaciones). 2) Machos realizan voces durante el comportamiento de exhibición en arenas de despliegue ("Trrrrrrrrrrr"; seis variaciones). 3) Machos posados en el suelo o en vuelo emiten trinos de baja frecuencia ("priIUpririririri"; tres variaciones). 4) Una hembra realizó una voz de llamada muy suave ("guaá-ku…”), posiblemente para contactarse con pichones. 5) Machos realizan sonidos mecánicos con las alas en las arenas de despliegue ("tuk" o "brrrt"; cuatro variaciones). Frente al avance humano sobre los pastizales del cono sur, es importante utilizar el conocimiento de estos sonidos para investigar otros aspectos de la historia natural como su biología reproductiva, distribución actual, movimientos estacionales, y efectos de fuego y otros disturbios en su hábitat y poblaciones.Abstract ∙ Vocalizations, mechanical sounds, and displays of the Sickle-winged Nightjar (Eleothreptus anomalus) in Argentina The Sickle-winged Nightjar (Eleothreptus anomalus) inhabits humid grasslands in southern South America and is considered “near threatened” because of its low abundance and habitat loss. The male is characterized by peculiar wings, shaped like an axe, with the primaries curved inward and the secondaries noticeably shorter, possibly an adaptation for producing mechanical sounds. It is speculated that its mating system is lek-like, with little evidence at present; its displays have not been described, and there is confusion about the origin and significance of its sounds. Here we contribute information about the sounds and displays of E. anomalus based on recordings and observations of a marked population at Reserva Natural Rincón de Santa María, Corrientes, Argentina (RNRSM; 2009–2018) and additional observations at Barra Concepción, Misiones, Argentina (2003–2004). In the last 9 years, we observed concentrations of up to 15 males displaying on two sections of elevated, little-used road in the RNRSM, which we consider display arenas, reinforcing the idea of a lek-mating system. We found five types of sounds. 1) Females and males make contact calls (series of "tik" o "tzk"; two variations). 2) Males vocalize during exhibition flights at display arenas ("Trrrrrrrrrrr"; six variations). 3) Males on the ground or in flight emit low-frequency trills ("priIUpririririri"; three variations). 4) A female emitted a very soft call ("guaá-ku…”), possibly to contact chicks. 5) Males make mechanical sounds with their wings at display arenas ("tuk" or "brrrt"; four variations). Considering how humans are advancing into the grasslands of the southern cone, it is important to use the knowledge of these sounds to investigate other aspects of natural history, such as reproductive biology, current distribution, seasonal movements, and effects of fire and other disturbance on habitat and populations

Gaps and Runs in Nest Cavity Occupancy: Cavity “Destroyers” and “Cleaners” Affect Reuse by Secondary Cavity Nesting Vertebrates

Many animals require tree cavities for breeding and these sites may be reused by a diversity of secondary cavity nesters over a timespan of decades. It is unknown whether the reuse of holes changes their desirability as nest sites. We hypothesized that some species, “cavity destroyers,” degrade the quality of holes by filling them with coarse nest material or waste whereas excavating species, “cavity cleaners,” might prolong the use of a hole by removing debris or enlarging the hole. Using data gathered during 22 years from a field study in central British Colombia, we analyzed long-term patterns of cavity occupancy in relation to their sequential use by bird and mammal species, grouped by traits. Patterns of cavity occupancy were variable with 49% of 875 large-sized holes (excavated by northern flickers Colaptes auratus and pileated woodpeckers Dryocopus pileatus) and 19% of 652 smaller-sized holes incorporating runs of sequential use that lasted to 18 years. About 11% of large and 25% of small cavities also had gaps of 3–13 years between occupancies. Mammals, raptors and European starlings, consistent with the hypothesis, were cavity destroyers, occupying cavities as terminal users and before gaps more often than expected by chance. The pattern of occupancy by northern flickers was random in relation to gaps or prior use by other species. Although flickers did not target old holes to clean, neither did they avoid them. Small cavities that were renovated by flickers into larger cavities were reused at twice the rate after renovation. Runs of cavity occupancy that involved only cavity-destroying species were shorter than runs that involved periodic use by flickers, suggesting the woodpecker, through its cleaning and renovation, prolonged the use of such holes. Our study contributes insights on additional ecological factors, namely previous users, that can influence the use and availability of cavities over time.Fil: Wiebe, Karen L.. University of Saskatchewan; CanadáFil: Cockle, Kristina Louise. University of British Columbia; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; ArgentinaFil: Trzcinski, M. Kurtis. University of British Columbia; CanadáFil: Edworthy, Amanda B.. University of British Columbia; CanadáFil: Martin, Kathy. University of British Columbia; Canad

Nesting of the Buff-fronted Owl (Aegolius harrisii) in Misiones, Argentina

Aunque el conocimiento de la distribución de la Lechucita Canela (Aegolius harrisii) se amplió notablemente en la última década, su biología permanece poco conocida. El conocimiento de la nidificación se basa en un solo nido confirmado, que no fue monitoreado, y una serie de observaciones de posibles nidos donde no fue comprobada la presencia de huevos o pichones. Entre diciembre de 2018 y enero de 2019, confirmamos y estudiamos un nido en una vieja cavidad excavada por una pareja de Carpintero Garganta Estriada (Dryocopus lineatus) a 9,6 m de altura en una grapia (Apuleia leiocarpa) muerta en selva Atlántica primaria del Parque Provincial Cruce Caballero, Misiones, Argentina. El nido contenía tres huevos blancos que eclosionaron en días alternos. Durante la incubación encontramos abundantes restos de escarabajos (Scarabaeidae: Coleoptera) debajo de la entrada del nido. Al nacer, los pichones tenían plumón natal gris oscuro muy ralo; a los 10 días empezaban a tener disco facial como el de los adultos; y a los 24 días se asemejaban a los adultos. Un adulto pasó todo el día dentro del nido desde la incubación hasta que el pichón mayor tenía 20?24 días de edad. Desde que nació el primer pichón hasta que voló el último los adultos trajeron por lo menos 32 roedores pequeños. Hubo un pico de aportes de alimentación justo después de la puesta del sol. Los tres pichones volaron exitosamente luego de 35?37 días, lo cual está en el límite superior del rango conocido para el Mochuelo Boreal (A. funereus) y el Mochuelo Cabezón (A. acadicus). No volvieron a utilizar la cavidad una vez que voló el último pichón. Aún es importante esclarecer el período de incubación, el rol de cada sexo en la reproducción y el rol de las cavidades (e.g., como dormidero) fuera del ciclo reproductivo.Nesting of the Buff-fronted Owl (Aegolius harrisii) in Misiones, Argentina Knowledge of the distribution of the Buff-fronted Owl (Aegolius harrisii) has increased notably in the last decade, but its biology remains poorly known. Knowledge of nesting is based on one confirmed nest, which was not monitored, and a series of observations of possible nests where the presence of eggs or nestlings was not confirmed. Between December 2018 and January 2019, we confirmed and studied a nest in an old cavity excavated by Lineated Woodpeckers (Dryocopus lineatus), 9.6 m above the ground in a dead garapa (Apuleia leiocarpa) tree, in primary Atlantic Forest at Parque Provincial Cruce Caballero, Misiones, Argentina. The nest contained three white eggs that hatched on alternate days. During incubation we found abundant beetle (Scarabaeidae: Coleoptera) remains below the nest entrance. On hatching, nestlings had sparse dark grey down; at 10 days old they began to have a facial disk like the adults; and by 24 days they looked similar to adults. One adult roosted in the nest all day from incubation until the oldest nestling reached 20–24 days of age. From when the first nestling hatched until the last nestling fledged, the adults brought at least 32 small rodents to the nest. There was a peak in prey delivery just after sunset. The three nestlings fledged successfully 35 to 37 days after hatching, which is at the high end of the range reported for Boreal (A. funereus) and Northern Saw-whet Owl (A. acadicus). They did not return to use the cavity once the last nestling had fledged. Further study is required to clarify the incubation period, the role of each sex in reproduction, and the role of cavities (e.g., for roosting) outside of the breeding cycle.Fil: Bodrati, Alejandro. Proyecto Selva de Pino Paraná, Misiones; ArgentinaFil: Gómez, Milka Raquel. Universidad Nacional de Misiones; Argentina. Proyecto Selva de Pino Paraná, Misiones; ArgentinaFil: Ferreyra, Carlos A.. Proyecto Selva de Pino Paraná, Misiones; ArgentinaFil: Cockle, Kristina Louise. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentin