Abstract Many aspects of the ecology, evolution and social behavior of wild-living primates remain un-explored and require further investigation. While long-term field studies are crucial for addressing conservation concerns for many primates’ species, acquiring the necessary data is often challenging, often due to difficulties in locating study groups. Radio-telemetry has significantly facilitated the study of primates and other animals living in tropical forests. However, there are important practical challenges in the process of capturing and releasing animals after placement of telemetry collars. In this study, we report guidelines and considerations for capturing and collaring wild capuchin monkeys, Sapajus nigritus cucullatus, in the Atlantic Forest of Argentina. Our ultimate goal is to contribute to making captures safer, preventing harm and stress to animals when using radio-telemetry in monitoring strategies for conservation of this primate species. These methods can be useful for researchers using field capture and radio-telemetry for monitoring groups or populations of wild primates, specifically wild Sapajus. ecology wildliving unexplored un explored investigation longterm long term species challenging Radiotelemetry Radio forests However collars monkeys cucullatus Argentina safer radiotelemetry radio

Several studies have observed that bat species respond differently to landscape changes and that individuals tend to expand their home range when the habitat is not optimal. Tropical dry forest in the Isthmus of Tehuantepec, Mexico, shows a high habitat loss and fragmentation by anthropogenic causes. However, how bats use this fragmented landscape is unknown. Therefore, the aim of this study was to describe the temporal and spatial movements of bats fitted with radio transmitters in a fragmented region of the Isthmus of Tehuantepec. In July 2011, six bats belonging to three species were captured: an adult female of Artibeus lituratus, a juvenile female of A. jamaicensis, an adult male of Leptonycteris yerbabuenae (Family Phyllostomidae), and three adult females of Pteronotus parnellii (Family Mormoopidae) were fitted with a radio transmitter. Bats were monitored during night (18:00 to 06:00 h) from fixed stations for 17 days. The activity was obtained by quantifying the frequency of bearings in intervals of one hour. Simultaneous bearings were triangulated for locations, which were exported to a vector map where type of land use and vegetation was determined. The home range was calculated using two techniques: minimum convex polygon and fixed Kernel. A total of 75 bearings corresponding to an adult female of A. lituratus (n = 36, 48.0 %), three adults females of P. parnellii (n = 30, 40.0 %), and an adult male of L. yerbabuenae (n = 8; 10.6 %) were obtained. A juvenile female of A. jamaicensis was located on one occasion (1.3 %). Female of A. lituratus showed activity between 19:00 and 23:00 h and between 24:00 and 05:00 h, with a peak between 03:00 y 04:00 h. This bat widely used the area with preference to riparian vegetation. Based on their locations, a home range (Kernel 95 %) of 8,394 hectares and a minimum convex polygon of 2,587 hectares were estimated. The male of L. yerbabuenae showed activity only between 22:00 and 02:00 h and their locations were on agriculture land (n = 2). The observed activity of P. parnellii began at 20:00 h, it was increased to at 22:00 h (one activity peak between 01:00 and 3:00 h) and gradually declined until 06:00 h. The three females of P. parnellii were located in agricultural land (n = 4) and cultivated pasture (n = 1). The home range of A. lituratus observed in the present study is the largest reported for phyllostomid bats, possibly in response to landscape condition. Activity and locations of three females of P. parnellii and a male of L. yerbabuenae suggest that they occasionally use the study area in their way to more productive areas.

Se ha observado que las especies de murciélagos responden de manera diferencial a los cambios en el paisaje y que los individuos tienden a ampliar su ámbito hogareño cuando el hábitat no es óptimo. Las selvas secas de la Planicie costera del Istmo de Tehuantepec, en México, presentan una alta pérdida y fragmentación por causas humanas. Sin embargo, se desconoce cómo los murciélagos usan este paisaje fragmentado. Por lo anterior, el objetivo de este estudio fue describir por primera vez los movimientos temporales y espaciales de murciélagos equipados con radio-transmisores en una zona fragmentada del Istmo de Tehuantepec. En julio de 2011 se capturaron seis murciélagos de tres especies: una hembra adulta de Artibeus lituratus, una hembra joven de A. jamaicensis, un macho adulto de Leptonycteris yerbabuenae (Familia Phyllostomidae) y tres hembras adultas de Pteronotus parnellii (Familia Mormoopidae), a los que se les adhirió un radio-transmisor. Durante 17 días de estudio, los murciélagos se buscaron a lo largo de la noche (18:00 a 06:00 h) desde estaciones fijas. La actividad se obtuvo al cuantificar la frecuencia de lecturas del rumbo en intervalos de una hora. Las lecturas de rumbo simultáneas fueron trianguladas para obtener puntos geográficos, mismos que se exportaron a un mapa vectorial en donde se determinó la cobertura de uso de suelo y vegetación. El área del ámbito hogareño se calculó mediante dos técnicas: polígono mínimo convexo y Kernel fijo. Se obtuvieron un total de 75 lecturas del rumbo, correspondientes a una hembra adulta de A. lituratus (n = 36, 48.0 %), tres hembras adultas de P. parnellii (n = 30; 40.0 %) y un macho adulto de L. yerbabuenae (n = 8; 10.6 %). Una hembra joven de A. jamaicensis se localizó en una sola ocasión (1.3 %). La hembra de A. lituratus mostró actividad entre las 19:00 y 23:00 h y entre las 24:00 y 05:00 h, con un pico entre las 03:00 y 04:00 h. Este murciélago usó ampliamente la zona con preferencia hacia vegetación ribereña. Con base en los puntos geográficos se le calculó un ámbito hogareño (Kernel 95 %) de 8,394 hectáreas y un polígono mínimo convexo de 2,587 hectáreas. Del macho de L. yerbabuenae solo se observó actividad entre las 22:00 y 02:00 h y las localizaciones estuvieron en áreas para agricultura (n = 2). El horario de actividad observado de P. parnellii comenzó a las 20:00 h, se incrementó hacia las 22:00 h (un pico de actividad entre las 01:00 y 3:00 h) y disminuyó gradualmente hasta las 06:00 h. Las tres hembras de P. parnellii se ubicaron en áreas agrícolas (n = 4) y en pastizal cultivado (n = 1). El ámbito hogareño de A. lituratus observado en el presente estudio es uno de los más grandes reportados para murciélagos filostómidos, posiblemente como respuesta a la condición del paisaje. Los puntos geográficos y horas de actividad de tres hembras de P. parnellii y de un macho de L. yerbabuenae sugieren que utilizan la zona ocasionalmente en su paso a otras áreas más productivas.

Abstract: Brocket deer inhabit two of the most threatened ecosystems in Mexico: the cloud forest and tropical evergreen forest, due to the lack of studies little is known about their current condition. However it is believed that it is threatened by various factors among them hunting, loss and fragmentation of habitat. In this paper we established a conceptual model a priori about the relationships between deer and their habitat where we included elements of microhabitat and landscape to determine how it affects the abundance and distribution of brocket deer in the mountains of the state of Hidalgo, Mexico. We selected 14 different forested sites, in each we established two transects 250 m long where the relative abundance of tracks was estimated. During April 2011 to March 2012 three sampling visit were made in each transect. In the transects we measured: forest structure, protective cover, low tree and shrub layer. For each site we considered the size and shape of the fragments and their matrix. To determine which variables influenced the abundance of tracks we used general linear regression models. 352 brocket deer tracks were recorded in 21 km of linear transects. The average relative abundance was 16.76 tracks/km. More tracks were found in sites with higher tree density 0.4 trees / m2, 60 % canopy cover, 70 % protection cover for fawns and 50 % for adults, higher linear density 0.5 ind / 25m and shrub richness of more than four species. The abundance of deer had a positive linear relationship with the density of tree coverage to protect adults and brocket deer importance value of edible trees (P < 0.001). The estimated abundance of tracks was higher than the reported in other sites. Our data suggest that the sites C2, C4 and C7 were better suited for deer use and possibly their movements to other sites attracted by some crops, but more specific studies would be necessary like radio-telemetry to test this assumption. This research indicated that brocket deer behaves like a forest specialist, as their abundance and welfare depends on food availability, habitat quality in terms of forest cover and the remoteness of settlements, which are generally the best preserved and most inaccessible fragments.

Resumen: El venado temazate habita en dos de los ecosistemas más amenazados en México: los bosques mesófilos de montaña y selvas. Debido a la falta de estudios poco se sabe acerca de su estado actual de conservación. Sin embargo, se cree que está amenazada por diversos factores entre los que destacan la cacería y la pérdida y fragmentación de su hábitat. En este trabajo establecimos un modelo conceptual a priori sobre las relaciones venado-hábitat donde incluimos elementos del microhábitat y del paisaje para determinar cómo afecta la fragmentación del paisaje y sus factores secundarios en la abundancia y distribución del temazate en las montañas de Hidalgo México. Elegimos 14 sitios con diferente cobertura forestal, en cada uno establecimos dos transectos en franja de 250 metros de largo por un metro de ancho, donde se calculó la abundancia relativa con conteo de rastros. Se realizaron tres visitas a cada transecto en franja durante el periodo abril 2011-marzo 2012. Además, se midió: estructura forestal, cobertura de protección, estrato arbustivo y arbóreo bajo. También para cada sitio analizamos la configuración de los fragmentos con mediciones del tamaño y forma de los fragmentos de bosque y su matriz. Realizamos modelos lineales de regresión múltiple para determinar que variables influían en la abundancia de rastros. Se registraron 352 rastros de venado temazate en 21 km lineales de transectos en franja. El índice de abundancia relativa promedio fue de 16.76 rastros/km. Se observó mayor cantidad de rastros en sitios con densidad absoluta mayor a 0.4 árboles/m2, cobertura de dosel mayor al 60 %, cobertura de protección a crías mayor al 70 % y mayor a 50 % para los adultos, una densidad lineal mayor a 0.5 ind/25m y una riqueza de arbustivas mayor a cuatro especies. La abundancia de rastros de venado temazate tiene una relación lineal positiva con la densidad absoluta de árboles, cobertura de protección a venados temazate adultos y valor de importancia de árboles comestibles (P < 0.001). La abundancia promedio de rastros estimada para este estudio es mayor a la de otros sitios. Nuestros datos apuntan a que en conjunto los sitios C2, C4 y C7 albergan la mayor cantidad de individuos y que posiblemente se estén desplazando a los otros sitios atraídos por algunos cultivos, sin embargo serían necesarios estudios más específicos como los de radio telemetría para comprobar este supuesto. Los resultados de la investigación indican que el temazate se comporta como un especialista de interior de bosque, ya que su abundancia depende de la disponibilidad de alimento, la calidad del hábitat en cuanto a cobertura forestal y la lejanía de asentamientos humanos, que en general son los fragmentos mejor conservados y de más difícil acceso.

Dois grupos de mico leãozinho (Cebuella pygmaea) foram resgatados ao longo da margem esquerda do Rio Madeira durante o enchimento do reservatório da Usina Hidrelétrica Santo Antônio, em Rondônia, norte do Brasil. A reintrodução de ambos os grupos deu-se em áreas de floresta ombrófila densa aberta dentro da Área de Preservação Permanente do empreendimento. Após a reintrodução, empregou-se a técnica de radiotelemetria para o monitoramento dos animais por aproximadamente três meses. Cada um dos grupos manteve-se coeso e estabeleceu suas áreas de vida em regiões próximas àquelas onde foram soltos. A taxa de mortalidade foi de aproximadamente 7%. Este parece ser o primeiro trabalho a documentar a translocação de grupos completos de C. pygmaea e o primeiro a empregar com sucesso a radiotelemetria no monitoramento desta espécie. Este estudo, portanto, demonstra a factibilidade da translocação e do uso da radio-telemetria para monitorar C. pygmaea.

Two groups of pygmy marmoset (Cebuella pygmaea) were rescued along the left bank of the Madeira River during the formation of Santo Antônio Hydroelectric Dam reservoir in the state of Rondônia, Northern Brazil. Reintroduction of both groups occurred in areas of open Tropical rainforest located within the project´s Permanent Preservation Area. A post-release monitoring was conducted for three months using radio-telemetry. Individuals of each group remained together and settled in stable home ranges near their respective release sites. The mortality rate of translocated animals was about 7%. This seems to be the first report documenting the complete group translocation of C. pygmaea and the first to successfully employ radio-telemetry techniques in monitoring this species. This study demonstrated the feasibility of translocation and the use of radio-telemetry in monitoring C. pygmaea.

To determine movement patterns and home range of wild Greater Rhea (Rhea americana), two subadult males were radio-tracked during the non-breeding season in a relict grassland of San Luis Province, Argentina. The average home range was 452.8 ha, the average daily distance travelled was 1.08 km/day, and the maximum distance from the capture/release site was 13.66 km. Rheas showed differences in habitat types used throughout the day. Grasslands were more frequently used early in the morning and late in the afternoon, whereas cultivated pastures (Medicago sativa) were used at noon. Although data is considered preliminary due to the small sample size, the importance of this study is here emphasized because it provides the first records of the spatial ecology of wild individuals for this species.

Para determinar los patrones de movimiento y el área de acción de ñandúes (Rhea americana) silvestres, se capturaron dos machos subadultos durante la temporada no reproductiva en un relicto de pastizal en la provincia de San Luis, Argentina. Cada individuo fue monitoreado por radio telemetría. El área de acción promedio estimada fue de 452.8 ha, la distancia promedio recorrida de 1.08 km/día y la máxima distancia atravesada desde el sitio de captura de 13.66 km. Los ñandúes usaron diferencialmente el hábitat a lo largo del día. Los pastizales fueron más utilizados por la mañana y por la tarde y las pasturas cultivadas (Medicago sativa) al mediodía. Si bien los resultados de este estudio son preliminares debido al pequeño tamaño de muestra, representan el primer registro de la ecología espacial de individuos silvestres de esta especie.

En la región del Chaco boliviano la tortuga negra Geochelone carbonaria es un reptil importante para los pueblos indígenas por motivos de subsistencia y medicina tradicional. Sin embargo, el conocimiento de aspectos biológicos y ecológicos es muy pobre. El presente artículo describe áreas de acción para la especie en dos campamentos de investigación a largo plazo del Parque Nacional Kaa-Iya del Gran Chaco. El método principal empleado ha sido la radio-telemetría en quince individuos durante dos años. Las tortugas ocuparon áreas de acción de 50-600 ha, con territorios ocupados por machos unas tres veces más grandes que los territorios ocupados por hembras. Existe solapamiento territorial entre individuos de ambos sexos, hasta 96% entre individuos observados, con múltiples individuos solapados entre sí, y tanto machos como hembras desplazan sus áreas de acción entre épocas seca y húmeda. Las áreas de acción relativamente grandes para un animal de este tamaño en el Chaco, en combinación con cambios de áreas de acción entre época seca y húmeda, inclusive dentro de áreas protegidas, indica que la conservación de la tortuga negra en paisajes impactados por humanos requerirá de la provisión de recursos claves como son alimentos, agua y refugios adecuados cuando estos mismos escaseen. Como alternativa, los territorios indígenas y las propiedades ganaderas deberán resguardar reservas comunales y privadas superando las 1.000 ha para poder mantener poblaciones de tortugas en sus tierras.

In the Bolivian Chaco, the tortoise Geochelone carbonaria is an important reptile to indigenous people for subsistence purposes and in traditional medicine. In Bolivia the species is considered near threatened, while observations suggest it is less abundant near communities and cattle ranches. However, understanding of its biology and ecology is limited. As part of a landscape conservation program with indigenous land and wildlife management, this article describes research on ranging patterns for the species at two long-term research camps in the Kaa-Iya del Gran Chaco National Park. The principal research method is radio-telemetry with 15 individuals over a two-year period. The tortoises occupy home ranges of 50-600 ha, with males using ranges three times larger than females. Individual home ranges overlap, up to 96% between pairs of monitored individuals, with multiple individual ranges overlapping simultaneously, while many males and females shift their ranges between wet and dry seasons. The relatively large ranges for an animal of this size in the Chaco, combined with shifting ranges across seasons, even in protected areas, means that conservation of red-footed tortoises within human-impacted landscapes will require provision of key resources that include appropriate food, water, and shelter where these become scarce. Alternatively, indigenous territories and ranches will need to set aside communal and private reserves exceeding 1,000 ha in order to maintain tortoise populations on their lands.

In an ecological context, information on the movement and activity is important for understanding the requirements of habitat, resource usage patterns and the potential of interspecific interactions. The aim of this study was to examine the displacement pattern on daily activity and occupancy of substrates by Aegla manuinflata using radio-telemetry technique on field on Southern Brazil. Four adult males were monitored during nine days. The aeglids showed a significantly greater displacement toward upstream than downstream. Aegla manuinflata individuals showed higher displacement activity during the night period. Although activity was not constant: the animals spent one or more days without displacement. All aeglids showed locomotion activity concentrated between 11:43 p.m. and 02:25 a.m., although it was not restrict to sunset period and night. Individuals showed specific occupation of different types of substrate, but a pattern in the occupation of substrates as a function of the photoperiod was not observed. In this study, using a new technique for tracking aeglids, it was concluded that A. manuinflata is capable of actively dislocate throughout the stream, either toward upstream and downstream, passing through obstacles which may represent ability of re-colonization. The animals are more active during the night period, probably a strategy to avoid predators that are active during the day; the selection of substrate is not associated to sediment texture.

Um estudo preliminar sobre a aplicação de técnicas de radiotelemetria para descrever os movimentos de peixes no canal de transposição da UHE Itaipu (Rio Paraná), conhecido como "Canal da Piracema", foi realizado entre janeiro e fevereiro de 2004. Seis espécies (Prochilodus lineatus, Leporinus friderici, Schizodon borellii, Pseudoplatystoma fasciatum, Pterodoras granulosus e Cichla kelberi) totalizando 14 indivíduos foram marcadas com radiotransmissores via cirúrgica e esofágica e rastreados através de três estações fixas experimentais de radiotelemetria instaladas na porção superior do Canal. A implantação de transmissores através de cirurgia e a anestesia por óleo de cravo mostraram-se mais eficientes e de fácil manejo do que a imobilização por eletronarcose e a implantação intragástrica. A utilização de estações fixas para obtenção dos dados mostrou-se apropriada para rastrear os movimentos de diferentes espécies no canal de transposição de Itaipu. Três espécies (P. granulosus, S. borellii e C. kelberi) movimentaram-se para jusante após a soltura. Dois indivíduos de P. fasciatum e dois de P. lineatus migraram para montante, deixando o canal 7 e 10 dias e 2 e 24 dias após a soltura, respectivamente. Leporinus friderici foi a única espécie que não deixou o local de soltura até o final do estudo.

A preliminary study on the application of radio-telemetry techniques to describe the movements of fish in a bypass channel at Itaipu Dam (Paraná River), known as "Canal da Piracema," was carried out between January and February of 2004. Fourteen individuals of six species (Prochilodus lineatus, Leporinus friderici, Schizodon borellii, Pseudoplatystoma fasciatum, Pterodoras granulosus and Cichla kelberi) were intragastrically and surgically radiotagged and monitored by three experimental fixed radio-telemetry stations installed in the upper portion of the Canal. The surgical implantation of transmitters and the anesthesia using clove oil proved to be more efficient and allowed easier handling in comparison to intragastric implantation and electronarcosis immobilization. The use of fixed stations to obtain data was found to be very suitable for tracking movements of several different fish species in the Itaipu lateral channel. Three species (P. granulosus, S. borellii and C. kelberi) moved downstream after release. Two individuals of P. fasciatum and two of P. lineatus migrated upstream, leaving the channel 7 and 10 days and 2 and 24 days after release, respectively. Leporinus friderici was the only species that did not leave the release site until the end of the study period.

Micoureus demerarae (Thomas, 1905) é um marsupial de tamanho médio, cerca de 130 g, de hábito noturno e arborícola e dieta insetívora-onívora. No período de agosto de 2001 a julho de 2002, sete indivíduos, três machos e quatro fêmeas, foram acompanhados, através de rádio-telemetria, na Reserva Biológica União, Rio de Janeiro, com o objetivo de investigar e descrever os abrigos utilizados por essa espécie de marsupial. Foram localizados 58 abrigos, a maioria dos quais (70,7%) em palmeiras Iri Astrocaryum aculeatissimum (Schott) Burret e o restante em outras espécies de árvores (29,3%), uma diferença significativa (teste chi2; p < 0,005). Esta preferência por palmeiras não foi significativamente diferente entre os sexos (teste chi2; p = 0,920). Em 31 abrigos (53,4% do total) o local exato onde o animal se encontrava pode ser localizado: nas palmeiras os animais sempre estavam alojados no local de inserção dos pecíolos junto ao tronco e a uma altura média de 4,66 ± 1,36 m, enquanto nas demais espécies de árvores, sete animais estavam em emaranhados de cipós e dois em ocos, a uma altura média de 10,67 ± 2,75 m. Esta diferença de altura entre abrigos em iris e não iris foi significativa (teste Mann Whitney; p < 0,001). Os resultados indicam que as palmeiras iris são um importante recurso para M. demerarae. A preferência por A. aculeatissimum se deve provavelmente à maior proteção contra predadores exercida pelos numerosos espinhos presentes nesta espécie.

Micoureus demerarae (Thomas, 1905) is a medium-sized marsupial, around 130 g, with a nocturnal habit and insectivorous-omnivorous diet. From August 2001 to July 2002, seven individuals, three males and four females, were monitored with radio-telemetry in Reserva Biológica União, state of Rio de Janeiro, Brazil, aiming to investigate and describe the sleeping sites used by this marsupial. Fifty eight sleeping sites were located, most of which (70,7%) in palm trees Astrocaryum aculeatissimum (Schott) Burret, and the remaining in other tree species (29,3%), a significant difference (chi2 test; p < 0.005). The preference for this palm tree was not different between sexes (chi2 test; p = 0.920). It was possible to locate the exact place where the animal was hiding in 31 sleeping sites (53.4% of total) in palm trees the animals were always in the junction point of petioles and tree trunks, at an average height of 4.66 ± 1.36 m, while in the remaining tree species, seven individuals were in liana tangles and two in tree holes, at an average height of 10.67 ± 2.75 m. This height difference was significant (Mann Whitney test; p < 0.001). Results indicate that palm trees are important resources for M. demerarae. The observed preference for A. aculeatissimum is probably due to higher protection against predators made by the numerous spines of this palm tree species.

No período de agosto de 2001 a julho de 2002 a área de uso e o movimento de sete Micoureus demerarae (Thomas, 1905) (três machos e quatro fêmeas) foram acompanhados, através de rádio-telemetria, na Reserva Biológica União, Rio de Janeiro, sudeste do Brasil. Foi obtido um total de 436 localizações e estimou-se a área de uso através dos métodos Kernel fixo (95% das localizações) e polígono mínimo convexo (PMC), com 100 e 95% das localizações. A área de uso dos machos estimada pelo PMC (100%) variou de 5,4-24,2 ha e fêmeas de 0,3-10,7 ha. Áreas calculadas com Kernel (95%) foram 4-10,9 ha para machos e 1,3-5,9 ha para fêmeas. Os animais locomoveram em média 423 m/noite, com machos se deslocando mais (582,8 m/noite) que as fêmeas (335,1 m/noite) (Teste t; t = 3,609; p = 0,001). Concluímos que o rádio rastreamento proporcionou áreas de uso superiores ao de estudos tradicionais realizados com capturas em armadilhas, sugerindo que pode haver uma subestimativa quando a área coberta com armadilhas é relativamente pequena (1 ha ou menos). O rádio-rastreamento também indicou que M. demerarae, embora seja predominantemente arborícola e pesa cerca de 130 g, possui movimentos semelhantes em magnitude a marsupiais terrestres de maior porte, como Didelphis Linnaeus, 1758, Philander Linnaeus, 1758 and Metachirus (Desmarest, 1817).

From August 2001 to July 2002 the home range and movements of seven Micoureus demerarae (Thomas, 1905) (three males and four females) were investigated using radio tracking in the União Biological Reserve, state of Rio de Janeiro, south-eastern Brazil. A total of 436 locations was obtained and home range estimated with fixed Kernel (95% of data points), and minimum convex polygon (MCP) methods, with 100 and 95% of data points. Male home ranges estimated by MCP (100%) ranged from 5.4-24.2 ha and females from 0.3-10.7 ha. Corresponding figures calculated with Kernel (95%) were 4-10.9 ha for males and 1.3-5.9 ha for females. Animals travelled on average 423 m/night, with males travelling significantly further (582.8 m/night) than females (335.1 m/night) (t test, t = 3.609, p = 0.001). We concluded that radio tracking produced much larger home ranges than those estimated with traditional live-trapping techniques, suggesting that the latter might underestimate ranging when the area covered with traps is relatively small (ca. 1 ha or less). Radio tracking also indicated that M. demerarae, although predominantly arboreal and weighting only ca. 130 g., has movements similar in magnitude to larger-sized terrestrial didelphimorph marsupials, such as Didelphis Linnaeus, 1758, Philander Linnaeus, 1758 and Metachirus (Desmarest, 1817).

Adult anadromous rainbow trout (Oncorhynchus mykiss) from the Santa Cruz River were implanted with radio-transmitters in May 2000 as they ascended the river from the ocean to locate spawning areas, assess the range and timing of the spawning migration, and determine the composition of the spawning populations. Radio-tagged fish revealed geographic and temporal migration patterns and previously unidentified spawning areas. Telemetry data indicated that anadromous fish dwell and spawn in the main stem river. Range of the total detected upstream migration varied between 2-280 km. Spawning begins by mid winter and peaks in the spring, matching the raise in water temperature, which ranged from 4ºC at the beginning of the spawning season to 10ºC at the end of the season in December. This pattern is similar to that of trout indigenous to the Pacific Northwest, USA, in which a raise in the water temperatures stimulates the onset of spawning. The arrangement of spatial locations of anadromous fish also indicated that spawning occurs in different sections along the main stem, giving some credence to the idea that subdivision at the intra-population level may exist. These results provide strong support to the idea that anadromous fish are at present more closely related to resident fish occurring in the upper Santa Cruz River, while resident fish from the lower reaches of the river may well constitute a separate spawning aggregation.

El río Santa Cruz, en Patagonia, es el único ambiente en el mundo donde la trucha arco iris introducida desarrolló poblaciones migratorias facultativas, donde una fracción de los individuos completa su ciclo de vida enteramente en agua dulce, mientras que otros realizan migraciones periódicas al mar con fines tróficos. En otoño de 2000 se implantaron radiotransmisores en siete individuos anádromos durante su ascenso al río desde el océano al inicio de la migración reproductiva, a fin de localizar las áreas de desove dentro de la cuenca, determinar la duración de la temporada reproductiva y evaluar la composición de la población reproductiva. La re-localización de los peces radio-marcados reveló patrones generales de la migración reproductiva de estos peces y permitió identificar sus áreas de desove. Desde julio a diciembre de 2000, todos los peces radio-marcados fueron localizados en distintos sectores del cauce principal del río Santa Cruz. La distancia máxima recorrida por los individuos radiomarcados durante la migración reproductiva varió entre 2-280 km. La temporada de desove comenzó a mediados de invierno, alcanzando el nivel máximo hacia primavera. Hacia diciembre ninguno de los peces radio-marcados se encontraban en el río. El pico de desove coincidió con un ascenso notable de la temperatura promedio del agua, la cual se incrementó desde 4ºC a principios de la temporada hasta 10ºC hacia fines de la temporada reproductiva. Los datos de telemetría revelaron que las truchas anádromas utilizan distintas áreas de desove dentro del cauce principal, lo cual sugiere un cierto grado de segregación a nivel intra-poblacional. Estos resultados indicarían que la forma anádroma se encuentra más estrechamente relacionada con las truchas arco iris residentes del curso medio y superior que con las truchas residentes que habitan en la desembocadura del río, las cuales parecen constituir una unidad poblacional separada.

By means of radio-telemetry techniques, we study the diving behavior and feeding performance of adult Rock shags (Phalacrocorax magellanicus) from Punta Loma and Isla Vernacci, two colonies of the Patagonian coast, Argentina. In both colonies, Rock shags dived continuously (without diving bouts) during foraging trips (mean dive duration: 47-50 s, mean subsequent surface interval: 14-18 s) and showed high dive efficiencies (3.2-3.8, dive time/recovery time). Tracked birds from the two colonies spent 31- 35% of daylight hours at sea, diving (including dive and recovery times) for 92% of the foraging trip. They undertook many (2.6-3.7 trips/day) and prolonged (1.7-2.6 h) trips per day, and made a high number of dives per foraging trip (78-138). These results suggest a high foraging effort (diving time per foraging trip) for Rock shags from the two studied colonies, necessary to reach the daily food requirements. This high foraging effort could be associated with low prey abundance, the existence of a patchy and/or low quality food resource (in energetic terms), or both.

Entre 1996 y 1998 se estudió, por medio de técnicas de radiotelemetría, el comportamiento de buceo y alimentación del Cormorán Cuello Negro (Phalacrocorax magellanicus) en Punta Loma y en Isla Vernacci, dos colonias de reproducción de la costa patagónica. En ambas colonias, los cormoranes bucearon por períodos prolongados (47-50 s) seguidos por breves intervalos de recuperación en superficie (14-18 s) y presentaron eficiencias de buceo altas (3.2-3.8, tiempo de buceo/tiempo en superficie). Tanto en Punta Loma como en Isla Vernacci, las aves permanecieron en el mar casi un tercio del total de horas luz (31-35%), bucearon la mayor parte del tiempo que estuvieron fuera de la colonia (aprox. 90%), realizaron numerosos viajes de alimentación diarios (2.6-3.7 viajes/día), de duración prolongada (1.7-2.6 h) y desarrollaron un elevado número de buceos por viaje (78-138). Estos resultados sugieren un alto esfuerzo de alimentación (tiempo dedicado al buceo por viaje) para cubrir los requerimientos energéticos propios y alimentar a los pichones. Una reducida disponibilidad de alimento (distribución, abundancia y accesibilidad) y el bajo rendimiento energético de las presas consumidas podrían ser algunos de los factores responsables del alto esfuerzo de alimentación sugerido.

Three Didelphis marsupialis were radio tracked during late dry season (23 February-26 April, 1983) in agricultural area at 1500 m elevation in Central Valley, Costa Rica. All animals were nocturnally active, significantly more so between 2100-0300 h. Fifty diurnal den site locations were found, 96% inside tree cavities in living fence rows or abandoned squirrel nests in windbreaks. Two females occupied 3.4 and 3.1 ha 95% home ranges, moving an average 890 and 686 m nightly respectively. The male occupied a 5.6 ha 95% home range for 42 days overlapping 90% of females' home ranges. Over the next 15 days, he moved 1020 m south, establishing three temporary home ranges. During nocturnal movements, windbreaks and living fence rows were used in higher proportion than available, while pasture, roads and cultivated lands were used less then available within 100% home ranges. Abandoned coffee and spruce plantations, fruit orchards and overgrown pastures were used in equal proportions to availability in 100% home ranges. Opossum conservation techniques in coffee growing areas include promoting spruce windbreaks, living fence rows, and garbage dumps.