scholarly journals Kleptoparasitism and territoriality in the Snail Kite Rostrhamus sociabilis (Accipitriformes: Accipitridae) in the Complejo Güija, El Salvador

2018 ◽  
Vol 26 (4) ◽  
pp. 227-230
Author(s):  
Abizai Clemente Chinchilla-Rodríguez ◽  
Iliana Guadalupe Barias-Álvarez
Keyword(s):  
El Salvador ◽  
Snail Kite ◽  
Rostrhamus Sociabilis

scholarly journals Water Levels Affect Nest Success of the Snail Kite in Florida: AIC and the Omission of Relevant Candidate Models

The Condor ◽  
2002 ◽  
Vol 104 (1) ◽  
pp. 208-215 ◽  
Author(s):  
Steven R. Beissinger ◽  
Noel F. R. Snyder
Keyword(s):  
Nest Success ◽  
A Priori ◽  
Information Criterion ◽  
Water Levels ◽  
Spatial Effects ◽  
Factors Affecting ◽  
Snail Kite ◽  
Water Conditions ◽  
Rostrhamus Sociabilis ◽  
Definition Of

Abstract Dreitz et al. (2001) analyzed the factors affecting nest success of the Snail Kite (Rostrhamus sociabilis) in Florida. They concluded that success was unrelated to water levels because Akaike's Information Criterion rated models with water-level terms as poor compared to other models. Their suite of candidate models, however, did not include models with area-specific differences in the way that water levels affect nest success. We believe that such differences should have been included among the a priori models examined, and that their best model is neither ecologically informative nor useful for management. Using the same statistical methods, we reanalyze Dreitz et al.'s data on nesting success from the five areas with sufficient years and nests for analysis (comprising 89% of their 1542 nests) and show that, when spatial effects of water levels are included, water levels have an important influence on nest success over the entire range of water levels, not just during low water conditions. Furthermore, Dreitz et al.'s definition of nesting attempts excluded nests found during the 10–21 day pre-laying period, when many nests fail. Thus, they overestimated nest success and underestimated the amount of nesting activity under low water conditions. Low water conditions occur relatively frequently throughout much of the kite's range, and under these conditions few kites nest and even fewer fledge young. The effects of low water extend well beyond nest success, causing many kites to forgo nesting altogether, shortening the breeding season, and decreasing the opportunity for multiple brooding. Los Niveles de Agua Afectan el Éxito de Nidos de Rostrhamus sociabilis en Florida: Criterio de Información de Akaike y la Omisión de Modelos Potenciales Relevantes Resumen. Dreitz et al. (2001) analizaron los factores que afectan el éxito de anidación de Rostrhamus sociabilis en Florida. Ellos concluyeron que el éxito no está relacionado con los niveles de agua porque según el Criterio de Información de Akaike, los modelos que incluían términos relacionados con el nivel de agua eran de poco valor en comparación con otros modelos. Sin embargo, entre los modelos evaluados no incluyeron aquellos con diferencias específicas de área en la manera en que los niveles de agua afectan el éxito de los nidos. Nosotros creemos que dichas diferencias han debido ser incluidas en los modelos evaluados a priori y que su mejor modelo no es ecológicamente informativo ni útil en términos de manejo. Utilizando los mismos métodos estadísticos, reanalizamos los datos de éxito de anidación de Dreitz et al. de las cinco áreas que tenían suficientes años y nidos para analizar (comprendiendo el 89% de sus 1542 nidos). Demostramos que cuando se incluyen los efectos espaciales de los niveles de agua, éstos tienen una influencia importante en el éxito de los nidos en todo el rango de niveles de agua (no sólo en condiciones de aguas bajas). Más aún, la definición de intentos de anidación empleada por Dreitz et al. excluyó a aquellos nidos encontrados durante el período de 10 a 21 días pre-postura, cuando muchos nidos fracasan. Por lo tanto, ellos sobreestimaron el éxito de los nidos y subestimaron la cantidad de actividad de anidación en condiciones de aguas bajas. Las condiciones de aguas bajas se presentan con relativa frecuencia en gran parte del rango de distribución de R. sociabilis. Bajo esas condiciones, pocos individuos anidan y aún menos crían polluelos exitosamente. Los efectos de aguas bajas se extienden más allá del éxito de los nidos, causando que muchos individuos totalmente renuncien a anidar, acortando la época reproductiva y reduciendo las oportunidades de tener múltiples nidadas.

scholarly journals Recent increase in the distribution of the snail kite (Rostrhamus sociabilis) along the central Pacific Coast of México

2013 ◽  
Vol 84 (1) ◽  
pp. 388-391 ◽  
Author(s):  
Salvador Hernández-Vázquez ◽  
Ricardo Rodríguez-Estrella ◽  
Francisco Ramírez-Ortega ◽  
Juan Loera ◽  
Manuel Ortega
Keyword(s):  
Pacific Coast ◽  
Central Pacific ◽  
Snail Kite ◽  
Recent Increase ◽  
Rostrhamus Sociabilis

scholarly journals Isolating the roles of movement and reproduction on effective connectivity alters conservation priorities for an endangered bird

2018 ◽  
Vol 115 (34) ◽  
pp. 8591-8596 ◽  
Author(s):  
Ellen P. Robertson ◽  
Robert J. Fletcher ◽  
Christopher E. Cattau ◽  
Bradley J. Udell ◽  
Brian E. Reichert ◽  
...  
Keyword(s):  
Effective Connectivity ◽  
Conservation Strategies ◽  
Conservation Priorities ◽  
Snail Kite ◽  
Mobile Species ◽  
Successful Reproduction ◽  
Hierarchical Levels ◽  
Rostrhamus Sociabilis ◽  
Breeding Attempt ◽  
Do So

Movement is important for ecological and evolutionary theory as well as connectivity conservation, which is increasingly critical for species responding to environmental change. Key ecological and evolutionary outcomes of movement, such as population growth and gene flow, require effective dispersal: movement that is followed by successful reproduction. However, the relative roles of movement and postmovement reproduction for effective dispersal and connectivity remain unclear. Here we isolate the contributions of movement and immigrant reproduction to effective dispersal and connectivity across the entire breeding range of an endangered raptor, the snail kite (Rostrhamus sociabilis plumbeus). To do so, we unite mark–resight data on movement and reproduction across 9 years and 27 breeding patches with an integrated model that decomposes effective dispersal into its hierarchical levels of movement, postmovement breeding attempt, and postmovement reproductive success. We found that immigrant reproduction limits effective dispersal more than movement for this endangered species, demonstrating that even highly mobile species may have limited effective connectivity due to reduced immigrant reproduction. We found different environmental limitations for the reproductive component of effective dispersal compared with movement, indicating that different conservation strategies may be needed when promoting effective dispersal rather than movement alone. We also demonstrate that considering immigrant reproduction, rather than movement alone, alters which patches are the most essential for connectivity, thereby changing conservation priorities. These results challenge the assumption that understanding movement alone is sufficient to infer connectivity and highlight that connectivity conservation may require not only fostering movement but also successful reproduction of immigrants.

Snail Kite (Rostrhamus sociabilis)

2015 ◽  
Author(s):  
Brian E. Reichert ◽  
Christopher E. Cattau ◽  
Robert J. Fletcher, Jr. ◽  
Paul W. Sykes Jr. ◽  
James A. Rodgers Jr. ◽  
...  
Keyword(s):  
Snail Kite ◽  
Rostrhamus Sociabilis

scholarly journals Foraging activity of the snail kite, Rostrhamus sociabilis (Aves: Accipitridae) in wetlands of southern Brazil

2013 ◽  
Vol 73 (2) ◽  
pp. 245-252 ◽  
Author(s):  
FB Bergmann ◽  
HLC Amaral ◽  
DP Pinto ◽  
CC Chivittz ◽  
AM Tozetti
Keyword(s):  
Habitat Heterogeneity ◽  
Prey Availability ◽  
Handling Time ◽  
Foraging Strategy ◽  
Climate Factors ◽  
American Continent ◽  
Snail Kite ◽  
Direct Observations ◽  
Rostrhamus Sociabilis ◽  
Hunting Strategy

The snail kite (Rostrhamus sociabilis) is widely distributed in the American continent. Its specialised diet consists mostly of the gastropod mollusk Pomacea sp and its foraging strategy probably varies depending on the season, prey availability, and climate factors, which can be reflected in its semi-nomad behaviour. This study was aimed at examining the hunting strategy of the snail kite, and its association with climate factors and habitat heterogeneity. Direct observations of birds between January 2010 and March 2011 in southernmost Brazil revealed that hunting was still the predominant foraging strategy (79% of records) to capture mollusks. Despite morphological specialisations to extract mollusks from the shells, the handling time (average = 92.4 s) was twice as much the time between prey search and capture (average = 55 s). The increase in the number of mollusks ingested apparently occurs when the resting time on perches or any other substrates near the hunting sites decreases between successive unsuccessful attempts. The correlation between the number of consumed preys and the climatic variables examined was low. Regarding habitat heterogeneity, our findings suggest that birds forage preferentially in marshes with low vegetation, which may increase the access to mollusks. The hunting efficiency of the snail kite was high (76 % successful attempts) compared to those of other birds of prey.

Recent breeding range expansion of the endangered Snail Kite (Rostrhamus sociabilis) in Florida

2020 ◽  
Vol 132 (1) ◽  
pp. 183
Author(s):  
Caroline L. Poli ◽  
Sarah J. Dudek ◽  
Brian M. Jeffrey ◽  
Ellen P. Robertson ◽  
Robert J. Fletcher
Keyword(s):  
Range Expansion ◽  
Snail Kite ◽  
Breeding Range ◽  
Rostrhamus Sociabilis

scholarly journals Snail Kite Nest Success and Water Levels: A Reply to Beissinger and Snyder

The Condor ◽  
2002 ◽  
Vol 104 (1) ◽  
pp. 216-221
Author(s):  
Victoria J. Dreitz ◽  
Robert E. Bennetts ◽  
Brian Toland ◽  
Wiley M. Kitchens ◽  
Michael W. Collopy
Keyword(s):  
Temporal Variability ◽  
Meta Analysis ◽  
Nest Success ◽  
Water Levels ◽  
Spatial And Temporal Variability ◽  
Individual Study ◽  
Spatial And Temporal Scales ◽  
Snail Kite ◽  
Rostrhamus Sociabilis ◽  
Study Sites

AbstractBeissinger and Snyder present a commentary on our recent paper on spatial and temporal variability in nest success of Snail Kites (Rostrhamus sociabilis) in Florida (Dreitz et al. 2001). Beissinger and Snyder reanalyze a subset of data presented in our original paper to show that water levels have a significant influence on nest success. To make their argument, the authors conduct separate analyses for 5 of the original 11 wetlands; including only those having the most data. We agree with Beissinger and Snyder that water levels can affect nest success in some areas or years, as we stated in Dreitz et al. (2001). However, the purpose of our original paper was to examine the influences of nest success over broad spatial and temporal scales. When viewed in this context, using a meta-analysis, water levels alone explain only a small amount of the observed variation in nest success. One of the advantages of using a meta-analysis is that it uses all of the available data to provide an indication of the overall magnitude of an effect, which can easily be misinterpreted when viewed in a narrower context of individual study sites. We discuss the management implications of these alternative perspectives on water levels in light of their effect on habitat quality and persistence.Éxito de Nidificación de Rostrhamus sociabilis y Nivel del Agua: Respuesta a Beissinger y SnyderResumen. Beissinger y Snyder presentan un comentario sobre nuestro reciente trabajo que considera la variación espacial y temporal en el éxito de nidificación de Rostrhamus sociabilis en Florida (Dreitz et al. 2001). Beissinger y Snyder reanalizan un subconjunto de los datos presentados en nuestro trabajo original para mostrar que el nivel del agua tiene una influencia significativa en el éxito de nidificación. Para elaborar su argumento, los autores analizan separadamente 5 de los 11 humedales originales, incluyendo solamente aquellos con mayor cantidad de datos. Estamos de acuerdo con Beissinger y Snyder en que el nivel del agua puede afectar el éxito de nidificación en algunas áreas o años, como exponemos en Dreitz et al. (2001). Sin embargo, el propósito original de nuestro trabajo fue examinar los factores que influencian el éxito reproductivo a una escala espacial y temporal amplia. Vista de este modo, usando un meta-análisis, el nivel del agua por separado explica solamente una pequeña cantidad de la variación observada en el éxito de nidificación. Una de las ventajas de usar un meta-análisis es que utiliza todos los datos disponibles para indicar la magnitud global de un efecto, el cual puede ser fácilmente malinterpretado cuando es visto en un contexto másacotado basado en sitios de estudio individuales. Discutimos las implicancias de manejo de estas perspectivas alternativas sobre el nivel del agua en relación a su efecto sobre la calidad del hábitat y la persistencia.

Snail Kite (Rostrhamus sociabilis)

1995 ◽  
Author(s):  
Paul W. Sykes ◽  
James A. Rodgers ◽  
R. E. Bennetts
Keyword(s):  
Snail Kite ◽  
Rostrhamus Sociabilis
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