Spring diet of the neotropic cormorant (<i>Phalacrocorax olivaceus</i>) in the Bahía Blanca estuary, Buenos Aires, Argentina

Se describe la dieta del Biguá (<i>Phalacrocorax olivaceus</i>) en un ambiente marino–costero durante la primavera. Pese a ser una especie ampliamente distribuida en Argentina, sus hábitos tróficos han sido escasamente estudiados y, paradójicamente, fue declarada en 1981 como especie dañina o perjudicial en la provincia de Buenos Aires. Se analizaron un total de 200 egagrópilas de adultos y juveniles recolectadas durante cuatro visitas entre 2003 y 2006 en la Isla del Puerto, estuario de Bahía Blanca, provincia de Buenos Aires, Argentina. Se identificaron un total de 15 presas, siendo los peces óseos los dominantes en la dieta. La lucerna (<i>Porichthys porosissimus</i>), especie de hábitos bentónicos y sin valor comercial en la zona, fue la presa de mayor frecuencia de ocurrencia.The spring diet of the Neotropic Cormorant (<i>Phalacrocorax olivaceus</i>) in a coastal marine environment is described. This species is widely distributed in Argentina and their trophic habits have been scarcely studied. Paradoxically, in 1981 it was declared a “harmful species” in Buenos Aires Province. A total of 200 pellets from adults and juveniles were collected during four visits between 2003 and 2006 in the del Puerto Island, Bahía Blanca estuary, Buenos Aires Province, Argentina. A total of 15 prey items were recorded, with teleosts fishes as the most important items in the diet. The lucerna (<i>Porichthys porosissimus</i>), a benthic toadfish with no commercial value in this zone, was the most frequent prey

BODY CONDITION OF BREEDING VERMILION FLYCATCHERS (PYROCEPHALUS RUBINUS) VARIES BETWEEN AREAS WITH AND WITHOUT CATTLE RANCHING IN CENTRAL ARGENTINA

The body condition of birds may be conditioned by intrinsic (e.g., sex, age, migratory and breeding status) and extrinsic factors, such as anthropic activities (e.g., livestock raising). We describe the biometry and body condition of Vermilion Flycatchers (VEFL) according to sex and age and evaluate which factors best predict their body condition during the breeding season in the Espinal of central Argentina. The study area included “Parque Luro” Provincial Reserve and two nearby private ranches with livestock. We captured and banded VEFL using mist nets between October to February, from 2015 to 2019. We calculated the scaled mass indexes, which relates body mass to biometric measures (culmen, tarsus, and tail length, and wing chord) to choose the best indicator of body condition. As explanatory variables, we used the breeding condition of females in one model, breeding condition of males in another model, and in a final model we used date, year and site, and included all individuals. We banded 93 VEFL that did not vary according to age-dependent body size or reproductive condition. Nevertheless, females weighed more, had higher fat levels and shorter wings than males. The body condition was only explained by breeding site, being smaller in one ranch than the other ranch and the reserve. We highlight the importance of reserves and the need for further research to understand the ecological constraints that South American birds face, to promote their conservation

Human-wildlife conflicts in the southern yungas: What role do raptors play for local settlers?

Wildlife persecution due to human-wildlife conflict has become a serious concern for biodiversity conservation, especially for many endangered species. In this context, conservation approaches need to consider the socio-ecological dimensions of each particular situation. The aim of this study was to evaluate the existence, extent and social characteristics of Human-Raptor Conflicts (HRC) in the Southern Yungas region in northwestern Argentina. We conducted 115 semi-structured interviews in 21 sites and analyzed attitudes and associations between sociodemographic variables and the existence of HRC. Forty percent of interviewees showed negative attitudes towards raptors, mainly with those species considered livestock predators rather than poultry predators. A total of 11 species were regarded as conflictive because of predation on domestic animals, of which Andean condors showed the highest conflict. The only socio-demographic factor affecting conflicts was livestock and poultry rearing, independently of age, gender and occupation of interviewees. The fact that only 8.7% of interviewees reported taking direct actions towards conflictive species indicates a relatively peaceful coexistence of people with raptors. Nevertheless, negative attitudes towards Andean condor together with their extreme susceptibility to any increase in non-natural mortality indicate the need of an integral conservation approach to tackle future threats for this species’ conservation in the area.Fil: Salom, Amira. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Suárez, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Destefano, Cecilia Andrea. Universidad de Buenos Aires; ArgentinaFil: Cereghetti, Joaquín. No especifíca;Fil: Vargas, Félix Hernán. No especifíca;Fil: Grande, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentin

Body condition of breeding Vermillion Flycatchers (Pyrocephalus rubinus) varies between areas with and without cattle ranching in central Argentina

La condición corporal de las aves puede estar influenciada por aspectos intrínsecos (ej., sexo, edad, comportamiento migratorio y reproductivo) y extrínsecos, como la presencia de actividades antrópicas (ej., ganadería). En este trabajo se describe la biometría y la condición corporal del churrinche, según el sexo y la edad, y se establecen los factores que las condicionan durante la época reproductiva en la provincia fitogeográfica del Espinal del centro de Argentina. El área de estudio comprendió la Reserva Provincial Parque Luro y dos estancias privadas ganaderas aledañas. Se capturaron y anillaron churrinches empleando redes de niebla entre octubre y febrero, desde 2015 a 2019. Se calcularon índices de masa escalada, el cual relaciona la masa corporal con medidas biométricas (largos de culmen, tarso y cola y cuerda de ala) para escoger el mejor predictor de la condición corporal. Como variables explicativas se emplearon en un modelo el estado reproductivo de las hembras; en otro, el estado reproductivo de los machos y en otro la fecha, el año de la temporada y el sitio, contemplando todos los individuos. Se anillaron 93 churrinches que no difirieron según su edad en sus medidas biométricas, ni características de condición corporal, ni condición reproductiva. Sin embargo, las hembras presentaron mayor masa y niveles de grasa y tenían el ala más corta que los machos. La condición corporal del churrinche solo fue explicada por el sitio reproductivo, siendo menor en una de las estancias con ganadería, con respecto a la otra estancia y a la reserva. Se resalta la importancia de las áreas protegidas naturales para mantener a las poblaciones de aves y la necesidad de estudios futuros que establezcan los mecanismos que modulan la condición corporal de las aves migratorias australes del neotrópico para promover su conservación.The body condition of birds may be influenced by intrinsic (e.g., sex, age, migratory and breeding status) and extrinsic factors, such as anthropic activities (e.g., livestock raising). We described the biometry and body condition of Vermilion Flycatchers (VEFL) according to sex and age, and evaluated which factors best predict their body condition during the breeding season in the phytogeographic province of Espinal in central Argentina. The study area included Parque Luro Provincial Reserve and two nearby private ranches with livestock. We captured and banded VEFL using mist nets between October and February, from 2015 to 2019. We calculated scaled mass indices, which relates body mass to biometric measures (culmen, tarsus and tail lengths, and wing chord) to choose the best indicator of body condition. As explanatory variables, we used the breeding condition of females in one model, breeding condition of males in another model, and in a final model we used date, year, and site, and included all individuals. We banded 93 VEFL that did not vary according to age-dependent body size or reproductive condition. Nevertheless, females weighed more, had higher fat levels, and shorter wings than males. Body condition was only explained by breeding site, being smaller in one ranch than at the other ranch and the reserve. We highlight the importance of protected nature reserves to maintain bird populations and the need for further research to establish the mechanisms that modulate the body condition of Neotropical austral migrant birds to promote their conservation.Fil: Rebollo, María Emilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: Sarasola, José Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina. Universidad Nacional de La Pampa. Facultad de Ciencia Exactas y Naturales. Departamento de Recursos Naturales. Centro para el Estudio y Conservación de Aves Rapaces; ArgentinaFil: Jahn, Alex. Indiana University; Estados UnidosFil: Cereghetti, Joaquín. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentin

Breeding latitude predicts timing but not rate of spring migration in a widespread migratory bird in South America

1. Identifying the processes that determine avian migratory strategies in different environmental contexts is imperative to understanding the constraints to survival and reproduction faced by migratory birds across the planet. 2. We compared the spring migration strategies of Fork‐tailed Flycatchers (Tyrannus s. savana) that breed at south‐temperate latitudes (i.e., austral migrants) vs. tropi‐ cal latitudes (i.e., intratropical migrants) in South America. We hypothesized that austral migrant flycatchers are more time‐selected than intratropical migrants during spring migration. As such, we predicted that austral migrants, which mi‐ grate further than intratropical migrants, will migrate at a faster rate and that the rate of migration for austral migrants will be positively correlated with the onset of spring migration. 3. We attached light‐level geolocators to Fork‐tailed Flycatchers at two tropical breeding sites in Brazil and at two south‐temperate breeding sites in Argentina and tracked their movements until the following breeding season. 4. Of 286 geolocators that were deployed, 37 were recovered ~1 year later, of which 28 provided useable data. Rate of spring migration did not differ significantly between the two groups, and only at one site was there a significantly positive relationship between date of initiation of spring migration and arrival date. 5. This represents the first comparison of individual migratory strategies among con‐ specific passerines breeding at tropical vs. temperate latitudes and suggests that austral migrant Fork‐tailed Flycatchers in South America are not more time‐se‐ lected on spring migration than intratropical migrant conspecifics. Low sample sizes could have diminished our power to detect differences (e.g., between sexes), such that further research into the mechanisms underpinning migratory strategies in this poorly understood system is necessary.Facultad de Ciencias Naturales y Muse

How birds age? Chilean Elaenia as an example for the Neotropical bird species

Determining the age of birds is important to understand the demographic dynamic, since the effects of mortality factors may depend on the age of the individuals. Several methods have been used to determine the age of many European and North American bird species, but little is known about aging in Neotropical birds. The aim of our research was to evaluate the method for aging Chilean Elaenia (Elaenia chilensis) through individuals of known age. We used the palate color and feather molt limits of individuals of known age, together with the previously available proposals for aging this species to propose a new criterion for determining the age of Chilean Elaenias. Our criterion makes possible to differentiate adult individuals in the first, second, and third year since their born. We consider that our proposal will allow to advance towards more detailed research on the population dynamics of bird species in South America.Fil: Gorosito, Cristian Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; ArgentinaFil: Cereghetti, Joaquín. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Cueto, Víctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentin

The First Black-and-Chestnut Eagle ( Spizaetus isidori ) Nest Discovered in Argentina Reveals Potential Human–Predator Conflicts

Fil: Aráoz, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Jujuy. Universidad Nacional de Jujuy. Centro de Investigaciones y Transferencia de Jujuy; Argentina. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional.; ArgentinaFil: Grande, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina. Universidad Nacional de La Pampa. Facultad de Ciencia Exactas y Naturales. Departamento de Recursos Naturales. Centro para el Estudio y Conservación de Aves Rapaces; ArgentinaFil: Lopez, Carmen Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina. Universidad Nacional de La Pampa. Facultad de Ciencia Exactas y Naturales. Departamento de Recursos Naturales. Centro para el Estudio y Conservación de Aves Rapaces; ArgentinaFil: Cereghetti, Joaquín. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Vargas, Félix Hernán. The Peregrine Fund; Estados Unido

Crowned solitary eagle (Buteogallus coronatus) as accumulator of armadillo osteoderms in the archaeological record? An actualistic taphonomic study for central Argentina

To distinguish whether the presence of osteoderms of armadillos (Xenarthra, Dasypodidae) in the zooarchaeological and paleontological record can be assigned to anthropic action or predators is an interesting topic. The Crowned solitary eagle (Buteogallus coronatus, Accipitriformes, Accipitridae) is among the predators that usually consume armadillos. It is one of the largest South American birds of prey, inhabiting southern Brazil to northern Patagonia in Argentina. Prey remains of the armadillos Zaedyus pichiy, Chaetophractus villosus and C. vellerosus were collected in 13 breeding areas from two biogeographic regions including La Pampa and Mendoza provinces, central Argentina, during 2010-2012. The significant amount of carapaces, osteoderms, and cranial elements of armadillos accumulated in nests is a distinctive feature of the Crowned solitary eagle. These accumulations are taphonomically characterized by the presence of: 1) complete or almost complete flattened, depressed or book-shaped folded carapace; 2) scarce caudal armors and cephalic shields; 3) flexible bands, and scapular and pelvic shields well represented; 4) anterior region of scapular shields usually broken; 5) many isolated osteoderms broken, crenulated or with irregular borders; 6) posterior regions of skulls often with crenulated, broken or missing borders; 7) skulls with beak marks in the dorsal and posterior parts of the braincase, and in the palates; 8) some mandibles with the posterior part broken; 9) scarce, but well preserved limb bones; and 10) beak marks on scapulae and pelves. In addition, the information obtained from abandoned nests showed that these taphonomic features could have been altered by weathering. These observations can be used in subsequent studies of armadillo bone accumulations from open-air archaeological or paleontological sites from central Argentina, and other parts of America, inhabited by the Crowned solitary eagle, as well as in future revisions of samples.Fil: Montalvo, Claudia Inés. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Fernández, Fernando Julián. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Galmes, Maximiliano Adrian. The Peregrine Fund; Estados Unidos. Universidad Nacional de La Pampa. Facultad de Ciencia Exactas y Naturales. Departamento de Recursos Naturales. Centro para el Estudio y Conservación de Aves Rapaces; ArgentinaFil: Santillán, Miguel Ángel. The Peregrine Fund; Estados UnidosFil: Cereghetti, Joaquín. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentin

Biometry, body condition, reproductive status and molt of Tyrannus s. savana in central Argentina

[ES]: La condición corporal puede influir en diferentes procesos fenológicos que, a su vez, pueden ser desempeñados diferencialmente según la edad y sexo de los individuos. Presentamos la biometría, condición corporal, estado reproductivo y muda de la tijereta sabanera (Tyrannus s. savana), un migrante austral del Neotrópico. En La Pampa, Argentina, de octubre a febrero (2015-2018), realizamos la captura de individuos que fueron anillados y medidos de forma estándar. Ampliamos el rango de peso y cuerda del ala y reportamos por primera vez el largo de tarso y culmen. Como sucede generalmente en paseriformes, las hembras fueron menores a los machos, tanto en el peso de pichones como la cuerda de ala y largo de la cola de adultos. Durante la época reproductiva, mayoritariamente el acúmulo de grasa fue bajo y el desarrollo de la musculatura intermedio, el del parche de incubación alto y el de la cloaca bajo, como en la mayoría de los tiránidos. También, la presencia de muda fue generalmente baja, como se ha documentado previamente, y el desgaste de las remeras y rectrices fue moderado. Asimismo, las características no variaron temporalmente, a excepción del acúmulo de grasa y los desgastes de remeras y rectrices entre los años de las temporadas estudiadas y la disminución del peso y el aumento del desarrollo del parche de incubación con el avance de cada temporada reproductiva. Descripciones como estas son importantes porque existe una gran falta de conocimiento sobre la historia natural de muchas aves del Neotrópico, lo cual limita nuestra capacidad de constatar y frenar la alarmante pérdida de biodiversidad en la región.[EN]: Body condition may influence different phenological processes that, at the same time, may be performed differentially according to individual sex and age. We studied the biometry, body condition, breeding stage and feather molt of the Fork-tailed flycatcher (Tyrannus s. savana), a Neotropical austral migrant. Between October and February (2015-2018), we captured individual flycatchers in La Pampa, Argentina, which were banded and measured in a standardized fashion. We found larger wing chords and weights than previous studies, and tarsus and culmen lengths were reported for the first time. As is true for most passerines, females were smaller than males, both in nestling weight and in adult wing chord and tail length. During the breeding season, fat levels were mostly low, pectoral muscle scores were medium, brood patch development was high and cloacal protuberance development was low, as reported for most tyrant flycatchers. Additionally, active feather molt was mostly low, as has been previously documented, and wear of the remiges and rectrices was moderate. Also, these characteristics did not show temporal changes, except for the variation of fat levels and wear of the remiges and rectrices between breeding seasons, and a decrease in weight and greater brood patch development as the reproductive seasons progressed. Descriptions such as this are important because there exists a large gap in our understanding of the basic natural history of many Neotropical birds, which hinders our ability to address the alarming loss of biodiversity in the region.Este trabajo fue realizado con el aporte económico de la Fundação de Amparo à Pesquisa do Estado de São Paulo (#2012/17225–2) y por el estipendio de la Beca Interna Doctoral del CONICET de MER (2015-2020). LP-R contó con una ayuda del programa “Becas Iberoamérica - Santander Investigación”.Peer reviewe

Highly variable movements by Andean Flamingos ( Phoenicoparrus andinus ): implications for conservation and management

The Andean Flamingo ( Phoenicoparrus andinus ) is endemic to the central Andes Mountains, with the majority of the population distributed between Argentina, Bolivia, and Chile. It is the rarest of the six flamingo species on the planet and is one of the least studied flamingos. Little information exists about its annual cycle, including which wetlands individual Andean Flamingos use at different times of year, posing an obstacle to developing effective conservation planning for its populations. In 2020 and 2022, we attached GPS-enabled satellite transmitters to four Andean Flamingos in northwestern Argentina, tracking their movements throughout the year to provide an initial assessment of their movement patterns, including timing, rate, and distances of movements between wetlands. We found highly variable movement patterns between individual flamingos. After the breeding season, which they spend at high elevations, some flamingos moved northwards to overwinter in the central Andes of Bolivia, whereas others moved south to overwinter near sea level in the lowlands of central Argentina. All tracked flamingos moved rapidly between wetlands, some of which were used by multiple flamingos. One flamingo visited sites in Argentina, Bolivia, and Chile during one annual cycle, highlighting the need for international conservation cooperation. Given the growing threats to this species, including climate change and a recent, rapid increase in lithium mining, we call for further research on this and other flamingo species in the Andes