Effects of Frequency on the Directional Auditory Sensitivity of Northern Saw-Whet Owls (Aegolius acadicus).

Many animals use sound as a medium for detecting or locating potential prey items or predation threats. Northern saw-whet owls (Aegolius acadicus) are particularly interesting in this regard, as they primarily rely on sound for hunting in darkness, but are also subject to predation pressure from larger raptors. We hypothesized that these opposing tasks should favor sensitivity to low-frequency sounds arriving from many locations (potential predators) and high-frequency sounds below the animal (ground-dwelling prey items).

Account and Utilization of Blood Lipid Profiles: Lipid Levels Predicted Hemosporidian Infection in Migrating Northern Saw-Whet Owls of Eastern North America.

Noting lipidomic changes following the parasitism of migrating birds, the metabolic needs of which are primarily fueled by lipids, can deepen our understanding of host-parasite interactions. We identified lipids of migrating Northern saw-whet owls (Aegolius acadicus) using collision-induced dissociation mass spectrometry, compared the lipidomic signatures of hemoparasite-infected and noninfected individuals, and performed cross-validation analyses to reveal associations between parasite infection and lipid levels. We found significantly lower levels of lipid classes phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidylethanolamine (PE), phosphatidylcholine (PC), and sphingomyelin (SM) in infected Northern saw-whet owls than in the noninfected individuals.

Hearing in 3D: Directional Auditory Sensitivity of Northern Saw-Whet Owls (Aegolius acadicus).

Northern saw-whet owls (Aegolius acadicus) are nocturnal predators that are able to acoustically localize prey with great accuracy; an ability that is attributed to their unique asymmetrical ear structure. While a great deal of research has focused on open loop sound localization prior to flight in owls (primarily barn owls), directional sensitivity of the ears may also be important in locating moving prey on the wing. Furthermore, directionally sensitive ears may also reduce the effects of masking noise, either from the owls' wings during flight or environmental noise (e.

Mitochondrial DNA variation of the ruffed grouse (Bonasa umbellus).

Objective: The ruffed grouse, Bonasa umbellus, is broadly distributed across North America and displays considerable taxonomic diversity. Except for a genetic study of some western populations of ruffed grouse, nothing is known about genetic variation in other regions of Canada and the United States. Our objective is to examine patterns of mitochondrial DNA (mtDNA) variation in the ruffed grouse across western, central, and eastern parts of its distribution.

Effects of presentation rate and onset time on auditory brainstem responses in Northern saw-whet owls (Aegolius acadicus).

Monitoring auditory brainstem responses (ABRs) is a common method of assessing auditory processing in non-model species. Although ABRs are widely used to compare auditory abilities across taxa, the extent to which different features of acoustic stimuli affect the ABR is largely unknown in most non-mammalian species. The authors investigated the effects of varying presentation rate and onset time to determine how different features of acoustic stimuli influence the ABR in Northern saw-whet owls (Aegolius acadicus), a species known for their unique auditory adaptations and hunting abilities.

Frequency sensitivity in Northern saw-whet owls (Aegolius acadicus).

Northern saw-whet owls (Aegolius acadicus) are known for their unique asymmetrical ear structure and ability to localize prey acoustically, yet few attempts have been made to explore the auditory capabilities of this species. In this study, we evoked auditory brainstem responses (ABRs) with tonebursts to assess three main hypotheses regarding the evolution of auditory sensitivity: sender-receiver matching, ecological constraints, and phylogenetic/morphological constraints. We found that ABR amplitude increased with increasing stimulus level, which is consistent with results in other avian species.

Biomarkers of animal health: integrating nutritional ecology, endocrine ecophysiology, ecoimmunology, and geospatial ecology.

Diverse biomarkers including stable isotope, hormonal, and ecoimmunological assays are powerful tools to assess animal condition. However, an integrative approach is necessary to provide the context essential to understanding how biomarkers reveal animal health in varied ecological conditions. A barrier to such integration is a general lack of awareness of how shared extraction methods from across fields can provide material from the same animal tissues for diverse biomarker assays.

Ferruginous pygmy-owl (Glaucidium brasilianum) and eastern screech-owl (Megascopes asio): new hosts for Philornis mimicola (Diptera: Muscidae) and Ornithodoros concanensis (Acari: Argasidae).

While banding ferruginous pygmy-owls (Glaucidium brasilianum) and Eastern screech-owls (Megascops asio) in south Texas during 2004, we recorded Philornis mimicola (Diptera: Muscidae) and Ornithodoros concanensis (Acari: Argasidae) parasitizing nestlings. Inspection of nestlings revealed 54 P. mimicola and one O.