Search Results (4)

Diagnosing fractures in hummingbirds is challenging because of their small size. This study evaluated the diagnostic performance and inter-reviewer agreement of four imaging modalities—conventional radiography, dental radiography, micro-computed tomography (micro-CT), and three-dimensional (3D)-reconstructed images from micro-CT scans—for identifying fractures in 16 ruby-throated hummingbirds (Archilochus colubris) admitted to a wildlife hospital. Six independent reviewers, with or in training for a specialty in veterinary radiology or wildlife medicine, assessed randomized image sets. Gross dissection of the carcasses using dermestid beetle larvae established the gold standard. Diagnostic performance metrics—sensitivity, specificity, predictive values, and likelihood ratios—were calculated for each modality. Inter-reviewer agreement was assessed using Fleiss’ kappa. Our results demonstrated that advanced imaging techniques improved diagnostic performance and inter-reviewer agreement compared to traditional radiography. While specificity (>88%) was comparable to other small animal studies, the sensitivity did not exceed 50% across all modalities. This low sensitivity reflects the challenges posed by minimal fracture displacement and hummingbirds’ extremely small size. Only 3D images achieved high positive likelihood ratios and superior inter-reviewer agreement, highlighting the unique value of 3D visualization in complex anatomical evaluations. Overall, the minute structures of hummingbirds present inherent diagnostic limitations, underscoring that negative radiographic results must be interpreted cautiously, and the possibility of false negatives should prompt consideration of advanced or follow-up imaging when clinical suspicion persists. Full article

Hummingbirds are charismatic fauna that provide important pollination services, including in the continental US, where 15 species regularly breed. Compared to other birds in North America, hummingbirds (family Trochilidae) have a unique exposure route to pesticides because they forage on nectar. Therefore, hummingbirds may be exposed to systemic pesticides borne in nectar. They also may be particularly vulnerable to pesticide exposure due to their small size and extreme metabolic demands. We review relevant factors including hummingbird life history, nectar residue uptake, and avian bioenergetic considerations with the goal of clearly identifying and articulating the specific modeling challenges that must be overcome to develop and/or adapt existing modeling approaches. To help evaluate these factors, we developed a dataset for ruby-throated hummingbirds (Archilochus colubris) and other avian species potentially exposed to pesticides. We used the systemic neonicotinoid pesticide imidacloprid as an illustration and compared results to five other common current use pesticides. We use the structure of Pop-GUIDE to provide a conceptual modeling framework for implementation of MCnest and to compile parameter values and relevant algorithms to predict the effects of pesticide exposure on avian pollinators. Conservative screening assessments suggest the potential for adverse effects from imidacloprid, as do more refined assessments, though many important limitations and uncertainties remain. Our review found many areas in which current USEPA avian models must be improved in order to conduct a full higher-tier risk assessment for avian pollinators exposed to neonicotinoid insecticides, including addition of models suitable for soil and seed treatments within the MCnest environment, ability to include empirical residue data in both nectar and invertebrates rather than relying on existing nomograms, expansion of MCnest to a full annual cycle, and increased representation of spatial heterogeneity. Although this work focuses on hummingbirds, the methods and recommendations may apply more widely to other vertebrate pollinators. Full article

During the day, hummingbirds quickly metabolize floral nectar to fuel high metabolic demands, but are unable to feed at night. Though stored fat is the primary nocturnal metabolic fuel, it has been suggested that hummingbirds store nectar in their crop to offset fat expenditure in the night or to directly fuel their first foraging trip in the morning. We examine the use of crop-stored sugar in the nocturnal energy budget of ruby-throated hummingbirds (Archilochus colubris) using respirometry and ¹³C stable isotope analysis. Hummingbirds were fed a ¹³C-enriched sugar solution before lights-out and held in respirometry chambers overnight without food. Respirometry results indicate that the hummingbirds metabolized the sugar in the evening meal in less than 2 h, and subsequently primarily catabolized fat. Breath stable isotope signatures provide the key insight that the hummingbirds converted a substantial portion of an evening meal to fats, which they later catabolized to support their overnight metabolism and spare endogenous energy stores. These results show that the value of a hummingbird’s evening meal depends on how much of this energy was converted to fat. Furthermore, this suggests that evening hyperphagia is an important energy maximization strategy, especially during energetically expensive periods such as migration or incubation. Full article

Classical Greek literature presents a variety of speaking animals. These are not, of course, the actual voices of animals but human projections. In a culture that aligns verbal mastery with social standing, verbal animals present a conundrum that speaks to an anxiety about human communication. I argue that the earliest examples of speaking animals, in Homer, Hesiod and Archilochus, show a fundamental connection with Golden Age tales. Later authors, such as Plutarch and Lucian, look back on such cases from a perspective that does not easily accept notions of divine causation that would permit such fanciful modes of communication. I argue that Plutarch uses a talking pig to challenge philosophical categories, and that Lucian transforms a sham-philosopher of a talking-cock to undermine the very pretense of philosophical virtue. Full article