Translocation experiments, in which researchers displace animals and then monitor their movements to return home, are commonly used as tools to assess functional connectivity of fragmented landscapes. Such experiments are purported to have important advantages of being time efficient and of standardizing “motivation” to move across individuals. Yet, we lack tests of whether movement behavior of translocated birds reflects natural behavior of unmanipulated birds. We compared the routine movement behavior of a tropical hummingbird, the Green Hermit (Phaethornis guy), to that of experimentally translocated individuals. We tested for differences in site selection patterns during movement at two spatial scales (point and path levels). We also compared movement rates between treatments. Behaviors documented during translocation experiments reflected those observed during routine movements. At the point level, both translocated and non‐translocated birds showed similar levels of preference for mature tropical forest. At the path level, step selection functions showed both translocated and non‐translocated hummingbirds avoiding movement across non‐forested matrix and selecting streams as movement corridors. Movement rates were generally higher during translocation experiments. However, the negative influence of forest cover on movement rates was proportionately similar in translocation and routine movement treatments. We report the first evidence showing that movement behavior of birds during translocation experiments is similar to their natural movement behavior. Therefore, translocation experiments may be reliable tools to address effects of landscape structure on animal movement. We observed consistent selection of landscape elements between translocated and non‐translocated birds, indicating that both routine and translocation movement studies lead to similar conclusions regarding the effect of landscape structure and forest composition on functional connectivity. Our observation that hummingbirds avoid non‐forest matrix and select riparian corridors also provides a potential mechanism for pollen limitation in fragmented tropical forest.

Habitat loss and fragmentation influence species distributions and therefore ecological processes that depend upon them. Pollination may be particularly susceptible to fragmentation, as it depends on frequent pollinator movement. Unfortunately, most pollinators are too small to track efficiently which has precluded testing the hypothesis that habitat fragmentation reduces or eliminates pollen flow by disrupting pollinator movement. We used radio-telemetry to examine space use of the green hermit hummingbird (Phaethornis guy), an important ‘hub’ pollinator of understory flowering plants across substantial portions of the neotropics and the primary pollinator of a keystone plant which shows reduced pollination success in fragmented landscapes. We found that green hermits strongly avoided crossing large stretches of non-forested matrix and preferred to move along stream corridors. Forest gaps as small as 50 m diminished the odds of movement by 50%. Green hermits occurred almost exclusively inside the forest, with the odds of occurrence being 8 times higher at points with >95% canopy cover compared with points having <5% canopy cover. Nevertheless, surprisingly. the species occurred in fragmented landscapes with low amounts of forest (~30% within a 2 km radius). Our results indicate that although green hermits are present even in landscapes with low amounts of tropical forest, movement within these landscapes ends up strongly constrained by forest gaps. Restricted movement of pollinators may be an underappreciated mechanism for widespread declines in pollination and plant fitness in fragmented landscapes, even when in the presence of appropriate pollinators.

SummaryThe Hooded Grebe Podiceps gallardoi has been uplisted to globally 'Endangered' recently mainly because of the rapid population decline suffered within the last 20 years due to factors such as nest depredation by Kelp Gull Larus dominicanus as well as destruction of colonies by wind and lake desiccation. During a census of Hooded Grebes during the 2010/2011 breeding season we found a new predator that has not previously been mentioned, the American mink Neovison vison. One individual mink killed 33 Hooded Grebes and consequently destroyed one of the five colonies found in that breeding season. Due to the characteristics of the waterbird assemblage in the area, the impact of mink could be catastrophic. ResumenEl Macá Tobiano Podiceps gallardoi ha sido recientemente elevado a la categoría de globalmente 'Amenazado' debido a la rápida disminución poblacional sufrida en los últimos 20 años. Distintos factores fueron mencionados como posibles causas, como la depredación de nidos por la Gaviota Cocinera Larus dominicanus, destrucción de colonias por el viento, desecación de lagos y lagunas, etc. Durante la realización de censos en toda el área de distribución del Maca Tobiano en la temporada 2010/11 hallamos un nuevo depredador que nunca había sido mencionado como una posible amenaza, el Visón Americano Neovison vison. Solo un individuo de visón mató 33 adultos de Macá Tobiano y consecuentemente eliminó una de las cinco colonias halladas durante toda la temporada. Dadas las características de las comunidades de aves acuáticas de la zona el impacto de los visones puede llegar a producir una situación catastrófica.

Over the last two centuries, the Red-and-Green Macaw (Ara chloropterus) has become locally extinct in Argentina. In an attempt to restore its key ecosystem functions as both disperser and regulator of large-seeded plants, a reintroduction project was initiated at the Iberá National Park in northeastern Argentina. The ability of released individuals to find food is crucial, especially when working with captive-bred animals, as long-term establishment of a self-sustaining population depends on their short-term ability to exploit wild food sources. Monitoring of feeding habits is usually conducted through behavioral observation, but in recent years DNA metabarcoding has emerged as an alternative for obtaining highly resolved data on diet composition. In this study, we use a combination of both techniques to characterize the breadth and composition of the reintroduced macaws' diet. In addition, we compare the efficiency of both observational and molecular techniques to assess diet composition in a frugivorous bird. Individuals fed on a variety of plant species (n = 49) belonging to a broad phylogenetic spectrum (28 families). Dietary richness estimated by direct observation and DNA metabarcoding was similar, though smaller than the combination of the two datasets as both techniques detected at least 15 species not recorded by the other method. While the total number of detected species was higher for observational data, the rate of species-detection per sampling day was higher for DNA metabarcoding. These results suggest that a combination of both methods is required in order to obtain the most accurate account of the total diversity of the diet of a bird species. The ability of reintroduced macaws to successfully exploit local food resources throughout the year indicates a good level of adjustment to the release site, an important step towards the creation of a stable, self-sustaining population of Red-and-Green Macaws in Northern Argentina.