The migration ecology of North American turkey vultures wintering in the Neotropics: spatial and population dynamics

The spatial and population dynamics of avian scavengers are poorly understood. This information is key for management and conservation interventions that guarantee long-term species conservation. My goal in this dissertation is to fill information gaps on the movement ecology of New World vultures using the Turkey Vulture (Cathartes aura) as a model species. I used a continental-wide satellite telemetry dataset to study the migration ecology, space-use, and demography of the three North American breeding populations of Turkey Vultures wintering in the Neotropics during a 17-year period. I found that primary productivity, but not weather, triggered Turkey Vulture migratory behavior, migration initiated when primary productivity dropped at the end of the breeding and non-breeding season. Migratory connectivity was high at the species level (0.85, 95% CI: 0.74–0.94). However, I found evidence of intrapopulation segregation during the non-breeding season demonstrated by lower values of migratory connectivity in each population. I investigated how seasonality interacted with human disturbance, landscape composition and configuration to mediate patterns of geographic and environmental space-use, and annual and seasonal survival probabilities. Environmental space-use was best explained by landscape configuration. Geographic space-use exhibited a quadratic response to landscape configuration metrics, suggesting that Turkey Vultures maximize space-use in landscape with intermediate disturbance. Human disturbance, but not but not landscape composition and configuration, influenced survival rates in space and time. Overall annual survival averaged 0.87 (95% CI = 0.74 – 0.98). Mortality risk was low in western and central populations but was 3.7 times greater for vultures in the eastern population. Risk of mortality for all vulture populations increased with road density, and this was greater during the non-breeding and return migration seasons. My results suggest that spatial and population dynamics are affected at a continental scale by the energy landscape, intermediate disturbance and human disturbance. My dissertation emphasizes the importance of an integrative empirical-modeling approach to address questions on effects of resources availability and search efficiency in the spatial and population dynamics of avian scavengers

Avifauna of Dinira National Park, Venezuela

This is a preliminary inventory of the avifauna of Dinira National Park (DNP), northeastern of Venezuelan Andes, a region that is poorly known ornithologically. In the field work (30 days), 127 bird species (10 orders, 41 families) were recorded, ca. 9 % of the total birds known to Venezuela. From them, just three corresponding to endemic species (2.4 %) whereas 14 (11.0 %) were migrants. Also, new important range extensions were documented, especially for some birds previously reported in Táchira and Mérida states (Merganetta armata and Dendrocincla tyrannina). From recorded species 33 are threatened in different levels, but only five of them are protected by Venezuelan laws

New overwintering location of Burrowing Owl, Athene cunicularia hypugaea (Molina, 1782) (Strigidae) in Tennessee, USA, with diet assessed through pellets

Reporting new occurrence records of organisms is key to overcome the Wallacean shortfall. Here, we report the first sighting of a Burrowing Owl, Athene cunicularia (Molina, 1782), overwintering on a peninsula in the Tennessee River in Tennessee, USA, during boreal winters 2020–2022. Pellets from this bird showed combination of six species. This is the first record for the species in the Interior Plateau of the USA. Conditions supporting this bird and evidence of it overwintering bear to explore the environmental conditions that support this species in novel areas

Andean Condor (Vultur gryphus) in Ecuador: Geographic Distribution, Population Size and Extinction Risk.

The Andean Condor (Vultur gryphus) in Ecuador is classified as Critically Endangered. Before 2015, standardized and systematic estimates of geographic distribution, population size and structure were not available for this species, hampering the assessment of its current status and hindering the design and implementation of effective conservation actions. In this study, we performed the first quantitative assessment of geographic distribution, population size and population viability of Andean Condor in Ecuador. We used a methodological approach that included an ecological niche model to study geographic distribution, a simultaneous survey of 70 roosting sites to estimate population size and a population viability analysis (PVA) for the next 100 years. Geographic distribution in the form of extent of occurrence was 49 725 km2. During a two-day census, 93 Andean Condors were recorded and a population of 94 to 102 individuals was estimated. In this population, adult-to-immature ratio was 1:0.5. In the modeled PVA scenarios, the probability of extinction, mean time to extinction and minimum population size varied from zero to 100%, 63 years and 193 individuals, respectively. Habitat loss is the greatest threat to the conservation of Andean Condor populations in Ecuador. Population size reduction in scenarios that included habitat loss began within the first 15 years of this threat. Population reinforcement had no effects on the recovery of Andean Condor populations given the current status of the species in Ecuador. The population size estimate presented in this study is the lower than those reported previously in other countries where the species occur. The inferences derived from the population viability analysis have implications for Condor management in Ecuador. This study highlights the need to redirect efforts from captive breeding and population reinforcement to habitat conservation

Dispersal and Space Use of Captive-Reared and Wild-Rehabilitated Harpy Eagles Released in Central American Landscapes: Implications for Reintroduction and Reinforcement Management

Understanding the spatial context of animal movements is fundamental for the establishment and management of protected areas. We tracked, by telemetry devices, 31 captive-reared and 5 wild-rehabilitated Harpia harpyja and estimated the dispersal and space use after release in Mesoamerica. We evaluated the effectiveness of protected areas in the protection of home ranges and examined how individual traits, release methods and landscape features influenced the dispersal and home range using mixed-effects models. The mean post-release dispersal was 29.4 km (95% CI: 22.5–38.5), and the annual home ranges averaged 1039.5 km2 (95% CI: 627–1941). The home ranges were influenced by the release method, patch richness, patch and edge density and contagion. The currently protected areas in Mesoamerica may not be effective conservation units for this species. The Harpy Eagle average home range greatly exceeded the average size of 1115 terrestrial protected areas (52.7 ± 6.1 km2) in Mesoamerica. Due to their wide use of space, including transboundary space, Harpy Eagle conservation efforts may fail if they are not carefully coordinated between the countries involved. Future restoration efforts of umbrella forest-dwelling raptors should select release sites with highly aggregated and poorly interspersed forests. The release sites should have a buffer of approximately 30 km and should be located completely within protected areas

Dispersal and Space Use of Captive-Reared and Wild-Rehabilitated Harpy Eagles Released in Central American Landscapes: Implications for Reintroduction and Reinforcement Management

Understanding the spatial context of animal movements is fundamental for the establishment and management of protected areas. We tracked, by telemetry devices, 31 captive-reared and 5 wild-rehabilitated Harpia harpyja and estimated the dispersal and space use after release in Mesoamerica. We evaluated the effectiveness of protected areas in the protection of home ranges and examined how individual traits, release methods and landscape features influenced the dispersal and home range using mixed-effects models. The mean post-release dispersal was 29.4 km (95% CI: 22.5–38.5), and the annual home ranges averaged 1039.5 km2 (95% CI: 627–1941). The home ranges were influenced by the release method, patch richness, patch and edge density and contagion. The currently protected areas in Mesoamerica may not be effective conservation units for this species. The Harpy Eagle average home range greatly exceeded the average size of 1115 terrestrial protected areas (52.7 ± 6.1 km2) in Mesoamerica. Due to their wide use of space, including transboundary space, Harpy Eagle conservation efforts may fail if they are not carefully coordinated between the countries involved. Future restoration efforts of umbrella forest-dwelling raptors should select release sites with highly aggregated and poorly interspersed forests. The release sites should have a buffer of approximately 30 km and should be located completely within protected areas

Geographic distribution of Andean Condor (<i>Vultur gryphus</i>) in Ecuador.

<p>Blue dots are roosting sites surveyed during September 29–30, 2015. Red polygons represent the National System of Protected Areas. Green areas represent extent of occurrence (left) and area of occupancy (right).</p

Environmental predictors used to model geographic distribution of Andean Condor (<i>Vultur gryphus</i>) in Ecuador.

<p>Environmental predictors used to model geographic distribution of Andean Condor (<i>Vultur gryphus</i>) in Ecuador.</p

Demographic parameters used in the population viability analysis of Andean Condor (<i>Vultur gryphus</i>) in Ecuador.

<p>Demographic parameters used in the population viability analysis of Andean Condor (<i>Vultur gryphus</i>) in Ecuador.</p