Selección de sitios de nidificación y efecto del hábitat en el éxito reproductivo de Colaptes campestris (Carpintero Campestre) y Colaptes melanochloros (Carpintero Real) (Aves: Picidae) en talares bonaerenses

Este estudio tuvo como objetivo principal evaluar cómo las características del hábitat (medidas a distintas escalas) afectan la reproducción de dos especies de carpinteros (el Carpintero Real Colaptes melanochloros y el Carpintero Campestre Colaptes campestris). Particularmente, se caracterizaron los sitios utilizados para nidificar y se evaluó la potencial selección de variables ambientales a la hora de construir cavidades nuevas, comparando los árboles utilizados con aquellos disponibles en el ambiente. Por otro lado, se registraron los principales parámetros del ciclo reproductivo, incluyendo la supervivencia de nidos. Finalmente, se modelaron las relaciones entre los parámetros reproductivos y las características ambientales y temporales dentro del área de estudio. Durante tres temporadas reproductivas consecutivas (2015-2016, 2016-2017 y 2017- 2018) se monitorearon 157 intentos de nidificación, 58 de Carpintero Campestre y 99 de Carpintero Real. Los carpinteros utilizaron 120 cavidades, que ocurrieron en 111 árboles, siendo un ~80% en Tala. El Carpintero Campestre utilizó árboles que fueron de mayor tamaño y cavidades de mayor volumen que los utilizados por el Carpintero Real. El Carpintero Real tuvo mayor propensión a excavar, tendencia no encontrada en el Carpintero Campestre. Ambos carpinteros evitaron sitios poco fragmentados y con abundante cobertura de la vegetación, mientras que utilizaron árboles de tamaño intermedio, si se los compara con aquellos disponibles en el ambiente. La densidad de madera en los árboles utilizados para nidificar (0,4 g/cm3) fue menor que la disponible en el ambiente (0,5 g/cm3). El Carpintero Campestre nidificó entre mediados de septiembre y mediados de enero, demoró al menos 15 días en construir una cavidad nueva y fue de nidada simple, excepto en los casos donde falló el primer intento, cuando se detectó un intento posterior. El tamaño modal de puesta fue de 4 huevos, que fueron incubados durante 11-12 días, mientras que los pichones permanecieron en el nido entre 28 y 31 días. Los pichones alcanzaron un peso asintótico de 167 g y el punto de máximo crecimiento ocurrió a los 7,0 días de edad. El volumen de la cavidad estuvo negativamente asociado al crecimiento de los pichones de Carpintero Campestre. El Carpintero Real nidificó entre mediados de septiembre y principios de enero, demoró al menos 21 días en construir una cavidad nueva, fue de nidada simple y se observaron parejas intentando criar una segunda nidada en los casos donde el primer intento fracasó. El tamaño modal de puesta fue de 4 huevos, los huevos fueron incubados entre 11 y 13 días y los pichones permanecieron en la cavidad durante 26-30 días. Los pichones alcanzaron un peso asintótico de 119 g y el momento de máximo crecimiento fue a los 7,4 días de edad. Los pichones de ambas especies fueron afectados negativamente por la presencia de larvas del género Philornis. Se observó reducción de nidada en ambos carpinteros, dónde el último pichón de cada nidada tuvo tasas de supervivencia y de crecimiento menores a la de sus hermanos. Sobre el éxito reproductivo, la probabilidad que tuvo un nido de Carpintero Campestre de sobrevivir fue de 38%, mientras que esta probabilidad fue de 46% para el Carpintero Real. La tasa de supervivencia diaria (TSD) fue en incremento conforme avanzó el ciclo de nidificación del Carpintero Real, mientras que, en el Carpintero Campestre, la TSD tuvo una disminución al momento de la eclosión y fue en aumento en la etapa de pichones. En el Carpintero Real, la TSD fue menor al principio y al final de la temporada reproductiva, teniendo su pico el centro de la temporada, mientras que en el Carpintero Campestre la relación entre estas variables fue tal que a medida que avanzó la temporada reproductiva, disminuyó la TSD. Las nidadas de Carpintero Real fueron más exitosas en cavidades excavadas que en cavidades reutilizadas, tendencia no encontrada en el Carpintero Campestre. Así mismo, de manera general, las especies coincidieron en su tamaño de puesta, su período de incubación y en las variables que mejor modelaron la relación con la tasa de supervivencia diaria. Ninguna de las características ambientales observadas explicó la variación de la supervivencia de nidos. Ya que los carpinteros seleccionaron árboles que tuvieron menor densidad de madera que aquellos disponibles en el ambiente, la tala indiscriminada de sectores de bosque podría disminuir la abundancia de árboles con estas características. La presente tesis se concibe como un estudio detallado de la biología reproductiva de dos especies neotropicales de carpinteros y la relación que los distintos parámetros reproductivos tienen con el hábitat. Simultáneamente, representa uno de los primeros estudios en monitorear exhaustiva y prolongadamente las poblaciones de estas especies en estas latitudes.The main objective of this study consisted on assessing the effect of habitat structure (measured at different spatial scales) on two woodpecker species (the Green-barred Woodpecker Colaptes melanochloros and the Campo Flicker Colaptes campestris) breeding biology. As a particular objective, to describe nest sites and to assess nest site selection patterns when building new cavities, by comparing used sites against available sites. In addition, to register the main parameters within the nesting cycle, including nest survival. Finally, the last objective included modelling the relationship between the breeding parameters and the environmental and temporal features within the study site. Nest-cavities were monitored throughout tree consecutive breeding seasons (2015-2016, 2016-2017 y 2017-2018) and were detected 58 nesting attempts by the Campo Flicker and 99 by the Green-barred Woodpecker, accounting a total of 157 nesting attempts between both species. A total of 120 cavities were used in 111 trees, which were, in ~80% of the cases, Tala trees. Regarding this point, the Campo Flicker nested in trees and cavities that were greater than those used by the Green-barred Woodpecker. On the contrary, the Green-barred Woodpecker was prone to excavate a new cavity each year, a pattern not observed in the Campo Flicker. At a habitat scale, woodpeckers avoided less fragmented areas with higher vegetation cover at a habitat scale. Nevertheless, if compared with available trees, woodpeckers used trees that had an intermediate size and, moreover, used trees had lower wood density (~0,4 g/cm3) than available trees (~0,5 g/cm3). The Campo Flicker nested between mid-September and mid-January, built its cavities in, at least, 15 days and was single brooded, except pairs with a failed first attempt, which had a second attempt after the first one failed. Clutch size was 4 eggs, the incubation period lasted 11-12 days and nestlings remained in the nest between 28 and 31 days. Nestlings reached an asymptotic weight of 167 g and maximum growth was reached at an age of 7,0 days. In addition, nestling growth was negatively affected by each increment of cavity volume. The Green-barred Woodpecker nested between mid-September and early January, built its cavities in, at least, 21 days, was single brooded and a second attempt was found for breeding pairs with a failed first attempt. Clutch size was 4 eggs, incubation lasted 11-13 days and nestling period was 26-30 days. Nestlings reached an asymptotic weight of 119 g and reached their maximum growth when they were 7,4 days old. Both species nestlings were negatively affected by the presence of Philornis botfly larvae. In addition, younger nestlings within the brood had lower chance of survival and less maximum growth rate than their older brothers. An average Campo Flicker nest had a 38% chance of surviving the entire nesting cycle while this probability was 46% in the Green-barred Woodpecker. Daily survival rate (DSR) had a positive relationship with nest age in the Green-barred Woodpecker, but had its lower value at the hatching moment in the Campo Flicker, increasing again in the nestling stage. Moreover, in the Green-barred Woodpecker there was a DSR peak in the center of the breeding season and there was a negative relationship between time of breeding and DSR in the Campo Flicker. As a general point of view, species had similar clutch sizes, incubation periods and DSR variation was explained by the same variables. Although there were no habitat features that explained nest survival at a large scale, woodpeckers selected trees that had lower wood density than those available in the environment. This result suggests that indiscriminate tree logging could diminish the amount of trees with these characteristics (i.e. the preferred nesting features of these two woodpecker species). This thesis is proposed to be a detailed study of the breeding ecology of two Neotropical woodpecker species and the effects of habitat features in these. Simultaneously, it represents one of the first studies to exhaustively monitor these species populations within these latitudes.Facultad de Ciencias Naturales y Muse

Inusual apropiación de nido y pichones por parte de la Paloma Torcaza (<i>Zenaida auriculata</i>)

Reportamos un caso de apropiación interespecífica de nido en donde una Torcaza (Zenaida auriculata) usurpa el nido de un Zorzal Chalchalero (Turdus amaurochalinus). Ambos pichones, incluido un pichón parásito de cría, resultaron muertos tras la usurpación, a pesar de los enérgicos esfuerzos de los zorzales por recuperar el nido y de los repetidos intentos de la paloma para alimentar los pichones. Creemos que la Torcaza perdió sus propios pichones cerca del nido de zorzal y esto motivó la usurpación. Atribuimos el falso reconocimiento de los pichones a un subproducto hormonal causado por la pérdida de sus propios pichones, similar a lo observado en el Pingüino Emperador (Aptenodytes fosteri).We report a case of interspecific nest appropriation by the Eared Dove (Zenaida auriculata) on a nest of the Creamy‐bellied Thrush (Turdus amaurochalinus). The usurpation attempt resulted in the death of both nestlings, including a parasitic cowbird, despite forceful attempts by the thrushes to retake their nest and repeated attempts by the dove to feed the nestlings. We believe that the loss of the dove offspring from a nest in a neighboring tree could have triggered this behavior, which may be a hormonal byproduct caused by the recent loss of their own offspring, similar to what has been observed in Emperor Penguins (Aptenodytes fosteri).Facultad de Ciencias Naturales y Muse

Inusual apropiación de nido y pichones por parte de la Paloma Torcaza (<i>Zenaida auriculata</i>)

Reportamos un caso de apropiación interespecífica de nido en donde una Torcaza (Zenaida auriculata) usurpa el nido de un Zorzal Chalchalero (Turdus amaurochalinus). Ambos pichones, incluido un pichón parásito de cría, resultaron muertos tras la usurpación, a pesar de los enérgicos esfuerzos de los zorzales por recuperar el nido y de los repetidos intentos de la paloma para alimentar los pichones. Creemos que la Torcaza perdió sus propios pichones cerca del nido de zorzal y esto motivó la usurpación. Atribuimos el falso reconocimiento de los pichones a un subproducto hormonal causado por la pérdida de sus propios pichones, similar a lo observado en el Pingüino Emperador (Aptenodytes fosteri).We report a case of interspecific nest appropriation by the Eared Dove (Zenaida auriculata) on a nest of the Creamy‐bellied Thrush (Turdus amaurochalinus). The usurpation attempt resulted in the death of both nestlings, including a parasitic cowbird, despite forceful attempts by the thrushes to retake their nest and repeated attempts by the dove to feed the nestlings. We believe that the loss of the dove offspring from a nest in a neighboring tree could have triggered this behavior, which may be a hormonal byproduct caused by the recent loss of their own offspring, similar to what has been observed in Emperor Penguins (Aptenodytes fosteri).Facultad de Ciencias Naturales y Muse

First record of Crataegus monogyna Jacq. (Rosales: Rosaceae) in Buenos Aires province, Argentina

Crataegus monogyna Jacq. (Rosales: Rosaceae) is cited and collected for the first time for Buenos Aires province, Argentina. Its distribution is extended within Argentina and southern South America, since it was only known from Río Negro and Neuquén provinces in southern Argentina until nowFacultad de Ciencias Naturales y Muse

UNUSUAL NEST AND NESTLING APPROPRIATION BY THE EARED DOVE (ZENAIDA AURICULATA)

Abstract ∙ We report a case of interspecific nest appropriation by the Eared Dove (Zenaida auriculata) on a nest of the Creamy‐bellied Thrush (Turdus amaurochalinus). The usurpation attempt resulted in the death of both nestlings, including a parasitic cowbird, despite forceful attempts by the thrushes to retake their nest and repeated attempts by the dove to feed the nestlings. We believe that the loss of the dove offspring from a nest in a neighboring tree could have triggered this behavior, which may be a hormonal byproduct caused by the recent loss of their own offspring, similar to what has been observed in Emperor Penguins (Aptenodytes fosteri).Resumen ∙ Inusual apropiación de nido y pichones por parte de la Paloma Torcaza (Zenaida auriculata) Reportamos un caso de apropiación interespecífica de nido en donde una Torcaza (Zenaida auriculata) usurpa el nido de un Zorzal Chalchalero (Turdus amaurochalinus). Ambos pichones, incluido un pichón parásito de cría, resultaron muertos tras la usurpación, a pesar de los enérgicos esfuerzos de los zorzales por recuperar el nido y de los repetidos intentos de la paloma para alimentar los pichones. Creemos que la Torcaza perdió sus propios pichones cerca del nido de zorzal y esto motivó la usurpación. Atribuimos el falso reconocimiento de los pichones a un subproducto hormonal causado por la pérdida de sus propios pichones, similar a lo observado en el Pingüino Emperador (Aptenodytes fosteri)

Nesting biology of the Narrow-billed Woodcreeper (<i>Lepidocolaptes angustirostris</i>) in a southern temperate forest of central-east Argentina

We present data on the nesting biology of the Narrow-billed Woodcreeper (Lepidocolaptes angustirostris) in a natural forest in central-east Argentina. A total of 18 nests were found during four breeding seasons (2015–2019; from September to January), located in cavities (natural, artificial and woodpecker cavities). The incubation period lasted 16 days and eggs were larger than those from northern populations. Nestlings stayed in the nest for 17 days and we could measure nestlings at two nests. Within the forest, nests were built in large native trees. Seven nests were successful, nine were depredated and two were abandoned. The average nest daily survival rate (DSR) was estimated as 0.96, giving a cumulative chance of nest survival in a nesting cycle of 24%. Our study provides the first estimate of the nest DSR for the species and new records on the nesting biology of a poorly known Neotropical bird.Facultad de Ciencias Naturales y Muse

Inusual apropiación de nido y pichones por parte de la Paloma Torcaza (<i>Zenaida auriculata</i>)

Reportamos un caso de apropiación interespecífica de nido en donde una Torcaza (Zenaida auriculata) usurpa el nido de un Zorzal Chalchalero (Turdus amaurochalinus). Ambos pichones, incluido un pichón parásito de cría, resultaron muertos tras la usurpación, a pesar de los enérgicos esfuerzos de los zorzales por recuperar el nido y de los repetidos intentos de la paloma para alimentar los pichones. Creemos que la Torcaza perdió sus propios pichones cerca del nido de zorzal y esto motivó la usurpación. Atribuimos el falso reconocimiento de los pichones a un subproducto hormonal causado por la pérdida de sus propios pichones, similar a lo observado en el Pingüino Emperador (Aptenodytes fosteri).We report a case of interspecific nest appropriation by the Eared Dove (Zenaida auriculata) on a nest of the Creamy‐bellied Thrush (Turdus amaurochalinus). The usurpation attempt resulted in the death of both nestlings, including a parasitic cowbird, despite forceful attempts by the thrushes to retake their nest and repeated attempts by the dove to feed the nestlings. We believe that the loss of the dove offspring from a nest in a neighboring tree could have triggered this behavior, which may be a hormonal byproduct caused by the recent loss of their own offspring, similar to what has been observed in Emperor Penguins (Aptenodytes fosteri).Facultad de Ciencias Naturales y Muse

First record of Crataegus monogyna Jacq. (Rosales: Rosaceae) in Buenos Aires province, Argentina

Crataegus monogyna Jacq. (Rosales: Rosaceae) is cited and collected for the first time for Buenos Aires province, Argentina. Its distribution is extended within Argentina and southern South America, since it was only known from Río Negro and Neuquén provinces in southern Argentina until nowFacultad de Ciencias Naturales y Muse

Impacts of the invasive European Starling on two neotropical woodpecker species: agonistic responses and reproductive interactions

The European Starling (Sturnus vulgaris) – hereafter ‘starling’ – has been introduced in many countries, and its South American population recently started expanding exponentially. This invasive species has a worldwide negative impact on the breeding performance of woodpeckers, competing for cavity use. Nevertheless, information is still lacking regarding southern temperate neotropical woodpeckers nest defence strategies and starling effects on woodpeckers’ breeding performance. We monitored Campo Flicker (Colaptes campestris) and Green-barred Woodpecker (Colaptes melanochloros) nests in a native southern temperate forest of central-eastern Argentina, to detect interactions with starlings and to assess the effect of starlings presence on woodpeckers’ breeding performance. We assessed whether woodpeckers perform defensive behaviours against the starlings by exposing taxidermied starling models to woodpecker breeding pairs. We detected interactions with starlings at 11% of the nests. These nests had a significantly higher probability of being abandoned during the early stages (until the third incubation day), compared to nests without interactions. Moreover, woodpeckers attacked and made distress calls more frequently in response to the presentation of the starling, compared to predator and non-competing species models. We also documented evidence of joint nesting, as four breeding pairs of woodpeckers shared their nest chamber with starlings. Our results indicate that neotropical woodpeckers are more likely to abandon their cavity when they interact with starlings. As the starling is expanding quickly in Argentina, this information points at the need to develop management programmes to control the impacts of this invasive species on the native fauna, especially on species with conservation concerns.Facultad de Ciencias Naturales y Muse

Cooperative harassment strategy by the European Starling to usurp cavities and reproductive cost for the neotropical Green-barred Woodpecker

The European Starling (Sturnus vulgaris) is a cavity-nesting bird with great invasive potential. As a result of human intervention, this bird is now distributed across all continents (except Antarctica) and its distribution range is increasing at an alarming rate. The European Starling was introduced to Argentina in 1983 and is currently distributed across almost the entire country. It is considered one of the hundred most damaging invasive species in the world and constitutes a serious competitive threat to native cavity-nesting birds. Interactions between European Starlings and cavity-nesting birds generally have negative consequences on native bird populations, although there are still few reports in the literature that account for the degree of damage. In this study, we report for the first time details of the harassment strategy and subsequent cavity usurpation by European Starlings on a breeding pair of Green-barred Woodpeckers (Colaptes melanochloros) in an urban area of central-eastern Argentina. Over one breeding season, the woodpeckers excavated seven cavities, none of which were successful. In six of these reproductive attempts (86%) we recorded interactions with European Starlings and in five (71%) the cavity was usurped. On three occasions we recorded a cooperative harassment strategy by a group of European Starlings causing the woodpeckers to abandon the cavity. Our report is especially relevant if we consider the invasive potential of the European Starling worldwide and the frequently limited cavity supply in bird breeding habitats. Therefore, we encourage governmental authorities and environmental NGOs to take measures to control the populations of this aggressive invasive species.Instituto de Limnología "Dr. Raúl A. Ringuelet"Centro de Estudios Parasitológicos y de Vectore