Abstract Alloparental behavior includes a wide range of situations, from occasional fostering to adoption. It is usually the result of brood parasitism, brood adoption or brood mixing, but also due to nest switching. Interspecific alloparental behaviors are less widespread, but there are no key differences in mechanism of un-derlying behaviors. Some South American grebes are found sympatrically, and some of them usually reproduce on mixed colonies. Here we describe different conspecific and interspecific alloparental behaviors involving Silvery Grebe (Podiceps occipitalis), White-tufted Grebe (Rollandia rolland) and the critically endangered Hooded Grebe (Podicepsgallardoi). We discuss the implications of temporary adoption and potentially ‘true’ adoption, in particular for Hooded Grebes. Our observations show that alloparental behavior is possibly widespread among Neotropical grebes, and in the case of the Hooded Grebe we hypothesize that alloparental intraspecific feeding of non-related juveniles prior to migration could help to increase juvenile survival.

Resumen El comportamiento aloparental incluye una amplia gama de situaciones, desde el cuidado ocasional hasta la adopción. Por lo general, esto sucede como resultado del parasitismo de cría, la adopción o la mezcla de crías, pero también debido al cambio de nido. Los comportamientos aloparentales interespecíficos están menos extendidos, pero no existen diferencias clave en el mecanismo de los comportamientos subyacentes. Algunos macaes sudamericanos son simpátricos, y generalmente se reproducen en colonias mixtas. Aquí describimos diferentes comportamientos aloparentales conespecíficos e interespecíficos que involucran al Macá Plateado (Podiceps occipitalis), el Macá Cara Blanca (Rollandia rolland) y el críticamente amenazado Macá Tobiano (Podicepsgallardoi). Discutimos las implicancias de la adopción temporal y de la adopción “real”, en particular en el Macá Tobiano. Nuestras observaciones muestran que el comportamiento aloparental está posiblemente extendido entre los macaes neotropicales, y en el caso del Macá Tobiano, planteamos la hipótesis que la alimentación intraespecífica a juveniles no emparentados antes de la migración podría ayudar a aumentar la supervivencia de estos juveniles.

Abstract The similarity between parasites communities’ decay with distance and its analysis may explain important ecological process such host dispersion. Patagonia is inhabited by two armadillo species, Chaetophractus villosus and Zaedyus pichiy. In this study we describe and analyze the variation on helminth fauna of these armadillos in Patagonia compared with northern localities described in previous studies. A total of 49 armadillos were collected in Patagonia. Quantitative descriptors of parasite ecology were calculated and community structure of helminths was analyzed following the central-satellite species hypothesis. The parasite richness in Patagonia decreases almost 50% in both armadillos. Zaedyus pichiy present the same central species in Patagonia as in northern localities. For C. villosus central-satellite species analysis could not be applied. The loss of some helminths in Z. pichiy could be the result of lower temperatures or the absence of intermediate arthropods hosts. But in C. villosus the absence of some helminths with Patagonian distribution could be explained by its recent dispersion in Patagonia. Trichohelix tuberculata still being the only helminth in C. villosus introduced population of Tierra del Fuego.

Three migratory species of sheldgeese (Chloephaga spp.) make seasonal movements across a large portion of the Argentine territory. All three of these species have been affected by anthropogenic actions which have caused dramatic population drops, especially for the Ruddy-headed Goose (Chloephaga rubidiceps). Although telemetry techniques have rapidly advanced, knowledge of the migratory routes of many Neotropical birds is still incipient. The study of migration routes should be a top priority, especially when conservation and management actions are necessary along the main migratory routes. The goal of this work is to present new evidence of important stopover sites and concentration areas of migratory sheldgeese in eastern Patagonia. We conducted fieldwork during the fall, winter and spring of 2017, all of 2018 and the summer of 2019 in Chubut province, Argentina. We identified one stopover area for sheldgeese within a recently created protected area, the Parque Interjurisdiccional Marino Costero Patagonia Austral (PIMCPA), that could be a key site for the protection of the three species, in particular for the Ruddy-headed Goose. Results will provide input for decision-making processes during the design of future infrastructure projects already planned in eastern Patagonia along the migratory route of several species.

Tres especies de cauquenes (Chloephaga spp.) migratorios realizan movimientos estacionales a lo largo de gran parte del territorio argentino. Todas han sido afectadas por acciones antrópicas, lo cual ha causado declives dramáticos en sus poblaciones, especialmente en el Cauquén Colorado (Chloephaga rubidiceps). Si bien en la actualidad las técnicas de telemetría han avanzado, el conocimiento de las rutas migratorias de muchas aves del Neotrópico aún es incipiente. El estudio de las rutas migratorias debe ser prioritario, principalmente cuando acciones de conservación y manejo son necesarias a lo largo de las mismas. El objetivo del presente trabajo es dar a conocer nuevas evidencias de sitios de escala y áreas de concentración de cauquenes migratorios en el Este de la Patagonia. Trabajamos durante el otoño, invierno y primavera de 2017, todo el año 2018 y verano de 2019 en la provincia de Chubut, Argentina. Identificamos un área de escala para las tres especies, en el Parque Interjurisdiccional Marino Costero Patagonia Austral (PIMCPA), como sitio de gran importancia para la conservación de las tres especies durante la migración, particularmente para el cauquén colorado. Los resultados obtenidos podrían servir en la toma de decisiones durante futuros proyectos de infraestructura planeados en el Este de Patagonia a lo largo de las rutas migratorias de varias especies.

Abstract American mink (Neovison vison) is the most widespread invasive carnivore in Patagonia. Based on field surveys and historical records, we present novel and detailed information of the American Mink present distribution along 180km of the Río Negro. This invasion nucleus represents the most northeastern area recorded for the species, a new invaded ecoregion (Monte Oriental) and a new province with wild populations (Buenos Aires). We document the existence of a fur farm located in Carmen de Patagones and Viedma cities (1965-1974) that may have originated this focus. We recommend the prompt design and implementation of a control plan.

Resumen El visón americano (Neovison vison) es el carnívoro exótico invasor de mayor distribución en Patagonia. Basados en relevamientos de campo y archivos históricos se presenta información detallada sobre su actual distribución en 180 km del Río Negro. Este foco representa la distribución más noreste, un nuevo ambiente invadido (Monte Oriental) y una nueva provincia con poblaciones silvestres (Buenos Aires). Documentamos la existencia de un criadero en las ciudades de Carmen de Patagones y Viedma (1965-1974), que podría ser el origen de este foco. Recomendamos diseñar e implementar planes de monitoreo y control de manera urgente.

Armadillos are among the most common mammals in agroecosystems in Argentina. Their insectivorous/omnivorous food habits raise the question about their putative role as pest controllers. The aim of this study is to describe the prey items of five armadillo species and evaluate their possible role as natural pest controllers. The stomach contents of 12 Dasypus hybridus, 10 Chaetophractus vellerosus, 14 Chaetophractus villosus, 4 Tolypeutes matacus and 9 Zaedyus pichiy were analyzed. We described the diet and identified prey items to family level, whenever possible, and computed the frequency of occurrence (FO) and relative abundance of prey items. With these values, the Item Categorization Index (ICI) was calculated to classify the items in order of importance (primary, secondary and tertiary items). Shannon diversity index was also computed. The armadillos studied here consumed arthropod species belonging to families of phytosanitary importance such as Acrididae, Scarabaeidae, Tenebrionidae, Lepidoptera, Formicidae, and Termitidae. Only two armadillos showed primary items in their diet; Z. pichiy (ants and tenebrionids) and T. matacus (termites and scarabid larvae). Important pest arthropods had FO values close to or greater than 50% in the diet of all armadillos. Armadillos consumed arthropods that are important pests for agriculture, forestry, and wood construction. Even though this study was mainly focused on armadillos’ diet, we suggest that the presence of these native species could benefit the productivity and health of agroecosystems by reducing the need for harmful agrochemicals.

Alien species represent a threat to native biodiversity. The success of invasive species despite their reduced genetic diversity is known as “the genetic paradox”. The American mink (Neovison vison) was introduced in several regions of the world, like Europe, Asia and South America. In Argentina, they were introduced in the 1930’s by the fur industry and wild populations were established in Patagonia due to liberations and escapes. In this study, we analyzed the genetic diversity of a wild American mink population of northern Santa Cruz province and compared it with a captive population. We sequenced a 359-bp fragment of the mtDNA control region and found that genetic variability was similar between both groups. Like in other wild invasive populations, genetic variability was not reduced in the population of Santa Cruz, probably as a consequence of frequent releases and escapes from different sources of captive minks.

Las especies invasoras constituyen una amenaza para la biodiversidad nativa. El éxito de las especies invasoras pese a su baja variabilidad genética se conoce como “paradoja genética”. El visón americano (Neovison vison) fue introducido en varias regiones del planeta como Europa, Asia y América del Sur con fines peleteros. En Argentina fue introducido en la década de 1930 y, como resultado de la liberación de individuos en la naturaleza, lograron establecerse poblaciones silvestres en la región Patagónica. El objetivo del presente trabajo es estudiar la diversidad genética de una población asilvestrada de la provincia de Santa Cruz y compararla con la de una población en cautiverio. Analizamos un fragmento de 359 pb de la región control de ADN mitocondrial y encontramos índices de variabilidad similares entre la población silvestre y la población cautiva. Al igual que en poblaciones asilvestradas de otras regiones del planeta, no se observa una reducción en la variabilidad genética en la población silvestre de Santa Cruz, probablemente como consecuencia de liberaciones y escapes recurrentes desde diversas fuentes de cautiverio.

The introduction of the North American beaver (Castor canadensis) to Tierra del Fuego is a widely known example of a successful biological invasion. However, the origin and history of this introduction bears closer scrutiny. Using historical documentation we provide evidence that beaver introduction occurred as a single release event of 20 beavers from northern Manitoba, Canada. This not only clarifies the origin of the invasion, but also suggests that the beaver population of Patagonia descends from a smaller number of individuals than previously assumed.

La introducción del castor norteamericano (Castor canadensis) en Tierra del Fuego es un ejemplo ampliamente conocido de una invasión biológica exitosa. Sin embargo, el origen y la historia de su introducción merecen mayor análisis. Usando documentación histórica, presentamos evidencia de que la introducción del castor se originó en un único evento de liberación de 20 castores que arribaron desde el norte de Manitoba en Canadá. Esto no solo aclara el origen de la invasión, sino que sugiere que la población de castores en Patagonia deriva de un número de individuos menor que el que se asumía hasta el momento.

The American mink is a widespread invasive carnivore in Patagonia, and due to its foraging behavior that allows it to exploit a wide variety of prey, it is the exotic carnivore with the highest potential impact on the region's biodiversity. Available regional information on mink presence/absence, as well as abundance estimations, is scarce even though it is vital to plan management actions. Here, we integrate the confirmed distribution of mink in Patagonia with its potential presence for areas where information is lacking, based on the location of animal releases and estimated dispersal rates. We propose an Area Prioritization Tool (APT) for invasive species management by overlapping habitat suitability, current known range, colonization fronts and areas deemed important for biodiversity conservation. Among the prioritized areas, we selected three and suggested a Protocol for Eradication Tasks (PET), based on successful mink eradication experiences in Europe. Finally, we estimated the relative costs associated with the PET's implementation in each area. We present this work as a systematic, applied tool to show a feasible way to face the invasive species problems in Patagonia and their management.

Carnívoros invasores en Patagonia: Definiendo prioridades para su manejo usando el visón americano (Neovison vison) como caso de estudio: El visón Americano es una especie introducida con una amplia distribución en Patagonia y por su comportamiento de forrajeo es el carnívoro invasor con el mayor potencial para afectar a la biodiversidad en la región. La información disponible acerca de la presencia/ ausencia del visón en la región y de estimaciones poblacionales es muy escasa aun cuando esto es vital para la planificación de acciones de manejo. En este trabajo integramos la información disponible acerca de la presencia del visón hasta la fecha y evaluamos su presencia en sitios donde hay vacíos de información, basándonos en la ubicación de los puntos de liberación de individuos, distribución confirmada y estimaciones de la capacidad de dispersión. Proponemos una Herramienta de Priorización de Áreas (HPA) para definir sitios prioritarios para el manejo, superponiendo mapas de distribución de la especie, de hábitat adecuado y de áreas de importancia para la conservación de la biodiversidad. Entre las áreas prioritarias, seleccionamos tres y sugerimos un Protocolo de Tareas de Erradicación (PTE) como estrategia de manejo del visón americano, basado en experiencias de erradicación Europeas exitosas. Finalmente, estimamos costos relativos asociados a la implementación de tal PTE en cada una de las áreas seleccionadas. Presentamos este trabajo como una herramienta aplicada, enfocada en mostrar una forma simplificada para afrontar el problema de las especies invasoras en Patagonia y su manejo.

Biological invasions are one of the major threats to biodiversity and ecosystem functioning, and they provoke economic losses to productive systems. A wild population of the Red-Bellied Squirrel Callosciurus erythraeus, native to South-east Asia, has established in the province a Buenos Aires (Argentina) since 1973. The objective of this study is to assess the spatial distribution of the Red-Bellied Squirrel and describe the opinion of local inhabitants regarding the presence of this exotic species. We conducted 312 interviews in the district of Luján (original release site of this species) and other neighbouring districts, between August 2003 and March 2004. The area of the range distribution of squirrels was calculated using the minimum convex polygon method in a geographical information system. The present distribution of the Red-Bellied Squirrels (the only squirrel species present in this region) covers an area of approximately 680 km 2. The increment of the radial distribution of squirrels was larger during the last five years (1999-2004: 1.6 km/year) than in a previous period (1973-1999: 0.3 km/year). While some inhabitants and local producers reported that the squirrels caused economic damages (e.g. in fruit plantations, afforestations, electric and irrigation systems), other inhabitants enjoy the presence of this species given its ornamental value, as a pet and even as a tourist attraction. The latter may encourage the transport of squirrels creating new invasive points, as has already occurred in the province of Córdoba (Argentina), and generating one of the major difficulties to prevent further expansion of this species.

The Asiatic Red-Bellied Squirrel has been introduced into the Pampas Region, where a wild population has now been established and it is colonizing new areas. Hair tubes have been successfully used to assess the presence/absence of other species of squirrel through the identification of the collected hairs. The objectives of this study were to characterize the hairs of the Red-Bellied Squirrel and to test the use of hair tubes to detect the presence of this species. The study was conducted in the province of Buenos Aires, Argentina, from January to July 2004. Hairs from the back, head and tail have dark and light stripes while hairs from the belly are uniformly reddish brown. A multi-seriated medullar pattern was observed in the hairs of the back, head and belly, while the tail’s hairs showed a different medullar pattern that can be described as overlapped dark rings. Cuticle scales patterns corresponded to the normal mosaic type in the hairs of the tail, back, head and belly, and for the last three regions a different pattern was observed next to the hair bulb. Hair tubes were made of PVC tubes (25x6 cm) opened at both extremes. The tubes had an adhesive tape attached at both extremes and bait (peanuts and nuts) was offered in the centre. Given the arboreal habits of this squirrel, traps were placed on tree branches and inspected weekly. The hair tubes were successful in collecting hairs of the Red-Bellied Squirrel that can be distinguished from those of other mammals inhabiting the same area. Because this is quite a simple and inexpensive technique, we consider it an appropriate method to evaluate the presence of this alien species in the region.