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Trumpp KM, Mayer J, Roman CE, Kent M. Hearing Assessment of Free-Ranging Owls and Implications for Wildlife Rehabilitation: 31 Cases (2014-2023). J Avian Med Surg 2024; 38:75-82. [PMID: 38980816 DOI: 10.1647/avianms-d-23-00043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
Owls, members of the avian order Strigiformes, are nocturnal birds of prey that are found worldwide except for Antarctica. Traumatized, free-ranging owls are commonly presented to veterinary hospitals and wildlife rehabilitation facilities with the goal of providing medical care and rehabilitation to enable release back into their natural habitat. Minimal guidelines exist for the release of wildlife, and whereas a need for functional vision is described in raptors, assessing and evaluating hearing is usually not mentioned. This can be problematic for nocturnal predators because hearing is the primary sense utilized by owls when hunting and navigating in their dark environment. The brainstem auditory evoked response (BAER) test is a minimally invasive, objective assessment of hearing commonly used in companion animals. To the authors' knowledge, routine or standardized BAER evaluation has not been reported in traumatized, free-ranging owls. In the following retrospective study, 31 free-ranging owls presented to the University of Georgia Veterinary Teaching Hospital for known or suspected trauma or being found in a debilitated state underwent BAER testing to assess for the presence of complete sensorineural hearing loss. Similar to assessment of hearing in companion animals, the BAER test was elicited using a broad click stimulus delivered at 85 dB nHL. In all owls, qualitative assessment and peak latency measurements of the BAER test reflected hearing ability. This study highlights the importance of hearing in nocturnal raptors, how BAER testing can aid in decision making regarding rehabilitation, and provides a foundation for further investigation of hearing loss in traumatized owls. We suggest that veterinarians working with free-ranging owls in a rehabilitation setting should consider BAER testing as part of routine diagnostic testing.
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Affiliation(s)
- Kelsey M Trumpp
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, GA 30602, USA,
| | - Joerg Mayer
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, GA 30602, USA
| | | | - Marc Kent
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, GA 30602, USA
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McGee J, Nelson PB, Ponder JB, Marr J, Redig P, Walsh EJ. Auditory performance in bald eagles and red-tailed hawks: a comparative study of hearing in diurnal raptors. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:793-811. [PMID: 31520117 DOI: 10.1007/s00359-019-01367-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/26/2019] [Accepted: 08/28/2019] [Indexed: 12/19/2022]
Abstract
Collision with wind turbines is a conservation concern for eagles with population abundance implications. The development of acoustic alerting technologies to deter eagles from entering hazardous air spaces is a potentially significant mitigation strategy to diminish associated morbidity and mortality risks. As a prelude to the engineering of deterrence technologies, auditory function was assessed in bald eagles (Haliaeetus leucocephalus), as well as in red-tailed hawks (Buteo jamaicensis). Auditory brainstem responses (ABRs) to a comprehensive battery of clicks and tone bursts varying in level and frequency were acquired to evaluate response thresholds, as well as suprathreshold response characteristics of wave I of the ABR, which represents the compound potential of the VIII cranial nerve. Sensitivity curves exhibited an asymmetric convex shape similar to those of other avian species, response latencies decreased exponentially with increasing stimulus level and response amplitudes grew with level in an orderly manner. Both species were responsive to a frequency band at least four octaves wide, with a most sensitive frequency of 2 kHz, and a high-frequency limit of approximately 5.7 kHz in bald eagles and 8 kHz in red-tailed hawks. Findings reported here provide a framework within which acoustic alerting signals might be developed.
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Affiliation(s)
- JoAnn McGee
- Department of Speech-Language-Hearing Sciences and the Center for Applied and Translational Sensory Science, University of Minnesota, 164 Pillsbury Dr. SE, Minneapolis, MN, 55455, USA.
| | - Peggy B Nelson
- Department of Speech-Language-Hearing Sciences and the Center for Applied and Translational Sensory Science, University of Minnesota, 164 Pillsbury Dr. SE, Minneapolis, MN, 55455, USA
| | - Julia B Ponder
- The Raptor Center, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA
| | - Jeffrey Marr
- St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN, 55414, USA
| | - Patrick Redig
- The Raptor Center, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA
| | - Edward J Walsh
- Department of Speech-Language-Hearing Sciences and the Center for Applied and Translational Sensory Science, University of Minnesota, 164 Pillsbury Dr. SE, Minneapolis, MN, 55455, USA
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Wong SJ, Abrams KS, Amburgey KN, Wang Y, Henry KS. Effects of selective auditory-nerve damage on the behavioral audiogram and temporal integration in the budgerigar. Hear Res 2019; 374:24-34. [PMID: 30703625 PMCID: PMC6382589 DOI: 10.1016/j.heares.2019.01.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/04/2019] [Accepted: 01/22/2019] [Indexed: 10/27/2022]
Abstract
Auditory-nerve fibers are lost steadily with age and as a possible consequence of noise-induced glutamate excitotoxicity. Auditory-nerve loss in the absence of other cochlear pathologies is thought to be undetectable with a pure-tone audiogram while degrading real-world speech perception (hidden hearing loss). Perceptual deficits remain unclear, however, due in part to the limited behavioral capacity of existing rodent models to discriminate complex sounds. The budgerigar is an avian vocal learner with human-like behavioral sensitivity to many simple and complex sounds and the capacity to mimic speech. Previous studies in this species show that intracochlear kainic-acid infusion reduces wave 1 of the auditory brainstem response by 40-70%, consistent with substantial excitotoxic auditory-nerve damage. The present study used operant-conditioning procedures in trained budgerigars to quantify kainic-acid effects on tone detection across frequency (0.25-8 kHz; the audiogram) and as a function of duration (20-160 ms; temporal integration). Tone thresholds in control animals were lowest from 1 to 4 kHz and decreased with increasing duration as in previous studies of the budgerigar. Behavioral results in kainic-acid-exposed animals were as sensitive as in controls, suggesting preservation of the audiogram and temporal integration despite auditory-nerve loss associated with up to 70% wave 1 reduction. Distortion-product otoacoustic emissions were also preserved in kainic-acid exposed animals, consistent with normal hair-cell function. These results highlight considerable perceptual resistance of tone-detection performance with selective auditory-nerve loss. Future behavioral studies in budgerigars with auditory-nerve damage can use complex speech-like stimuli to help clarify aspects of auditory perception impacted by this common cochlear pathology.
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Affiliation(s)
- Stephanie J Wong
- Department of Otolaryngology, University of Rochester, Rochester, NY, 14642, USA
| | - Kristina S Abrams
- Department of Neuroscience, University of Rochester, Rochester, NY, 14642, USA
| | - Kassidy N Amburgey
- Department of Otolaryngology, University of Rochester, Rochester, NY, 14642, USA
| | - Yingxuan Wang
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, 14642, USA
| | - Kenneth S Henry
- Department of Otolaryngology, University of Rochester, Rochester, NY, 14642, USA; Department of Neuroscience, University of Rochester, Rochester, NY, 14642, USA; Department of Biomedical Engineering, University of Rochester, Rochester, NY, 14642, USA.
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Henry KS, Abrams KS. Persistent Auditory Nerve Damage Following Kainic Acid Excitotoxicity in the Budgerigar (Melopsittacus undulatus). J Assoc Res Otolaryngol 2018; 19:435-449. [PMID: 29744730 DOI: 10.1007/s10162-018-0671-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/22/2018] [Indexed: 11/30/2022] Open
Abstract
Permanent loss of auditory nerve (AN) fibers occurs with increasing age and sound overexposure, sometimes without hair cell damage or associated audiometric threshold elevation. Rodent studies suggest effects of AN damage on central processing and behavior, but these species have limited capacity to discriminate low-frequency speech-like sounds. Here, we introduce a new animal model of AN damage in an avian communication specialist, the budgerigar (Melopsittacus undulatus). The budgerigar is a vocal learner and speech mimic with sensitive low-frequency hearing and human-like behavioral sensitivity to many complex signals including speech components. Excitotoxic AN damage was induced through bilateral cochlear infusions of kainic acid (KA). Acute KA effects on cochlear function were assessed using AN compound action potentials (CAPs) and hair cell cochlear microphonics (CMs). Long-term KA effects were assessed using auditory brainstem response (ABR) measurements for up to 31 weeks post-KA exposure. KA infusion immediately abolished AN CAPs while having mild impact on the CM. ABR wave I, the far-field AN response, showed a pronounced 40-75 % amplitude reduction at moderate-to-high sound levels that persisted for the duration of the study. In contrast, wave I latency and the amplitude of wave V were nearly unaffected by KA, and waves II-IV were less reduced than wave I. ABR thresholds, calculated based on complete response waveforms, showed no impairment following KA. These results demonstrate that KA exposure in the budgerigar causes irreversible AN damage, most likely through excitotoxic injury to afferent fibers or synapses as in other species, while sparing ABR thresholds. Normal wave V amplitude, assumed to originate centrally, may persist through compensatory mechanisms that restore central response amplitude by downregulating inhibition. Future studies in this new animal model of AN damage can explore effects of this neural lesion, in isolation from hair cell trauma and threshold elevation, on central processing and perception of complex sounds.
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Affiliation(s)
- Kenneth S Henry
- Department of Otolaryngology, University of Rochester, 601 Elmwood Ave., Box 629, Rochester, NY, 14642, USA.
| | - Kristina S Abrams
- Department of Otolaryngology, University of Rochester, 601 Elmwood Ave., Box 629, Rochester, NY, 14642, USA.,Department of Neuroscience, University of Rochester, Rochester, NY, USA
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Kettler L, Christensen-Dalsgaard J, Larsen ON, Wagner H. Low frequency eardrum directionality in the barn owl induced by sound transmission through the interaural canal. BIOLOGICAL CYBERNETICS 2016; 110:333-343. [PMID: 27209198 DOI: 10.1007/s00422-016-0689-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 05/09/2016] [Indexed: 05/22/2023]
Abstract
The middle ears of birds are typically connected by interaural cavities that form a cranial canal. Eardrums coupled in this manner may function as pressure difference receivers rather than pressure receivers. Hereby, the eardrum vibrations become inherently directional. The barn owl also has a large interaural canal, but its role in barn owl hearing and specifically in sound localization has been controversial so far. We discuss here existing data and the role of the interaural canal in this species and add a new dataset obtained by laser Doppler vibrometry in a free-field setting. Significant sound transmission across the interaural canal occurred at low frequencies. The sound transmission induces considerable eardrum directionality in a narrow band from 1.5 to 3.5 kHz. This is below the frequency range used by the barn owl for locating prey, but may conceivably be used for locating conspecific callers.
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Affiliation(s)
- Lutz Kettler
- Department of Biology, Center for Comparative and Evolutionary Biology of Hearing, University of Maryland College Park, College Park, MD, 20742, USA.
- Department of Zoology and Animal Physiology, Institute of Biology II, RWTH Aachen, Worringerweg 3, 52074, Aachen, Germany.
| | | | - Ole Næsbye Larsen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Hermann Wagner
- Department of Zoology and Animal Physiology, Institute of Biology II, RWTH Aachen, Worringerweg 3, 52074, Aachen, Germany
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Larsen ON, Christensen-Dalsgaard J, Jensen KK. Role of intracranial cavities in avian directional hearing. BIOLOGICAL CYBERNETICS 2016; 110:319-331. [PMID: 27209199 DOI: 10.1007/s00422-016-0688-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 05/03/2016] [Indexed: 05/22/2023]
Abstract
Whereas it is clear from anatomical studies that all birds have complex interaural canals connecting their middle ears, the effect of interaural coupling on directional hearing has been disputed. A reason for conflicting results in earlier studies may have been that the function of the tympanic ear and hence of the interaural coupling is sensitive to variations in the intracranial air pressure. In awake birds, the middle ears and connected cavities are vented actively through the pharyngotympanic tube. This venting reflex seems to be suppressed in anesthetized birds, leading to increasingly lower pressure in the interaural cavities, stiffening the eardrums, and displacing them medially. This causes the sensitivity, as well as the interaural coupling, to drop. Conversely, when the middle ears are properly vented, robust directional eardrum responses, most likely caused by internal coupling, have been reported. The anatomical basis of this coupling is the 'interaural canal,' which turns out to be a highly complex canal and cavity system, which we describe for the zebra finch. Surprisingly, given the complexity of the interaural canals, simple models of pipe-coupled middle ears fit the eardrum directionality data quite well, but future models taking the complex anatomy into consideration should be developed.
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Affiliation(s)
- Ole Næsbye Larsen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark.
| | | | - Kenneth Kragh Jensen
- Starkey Hearing Technologies, 6600 Washington Ave. S, Eden Prairie, MN, 55344, USA
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Christensen-Dalsgaard J. Vertebrate pressure-gradient receivers. Hear Res 2010; 273:37-45. [PMID: 20727396 DOI: 10.1016/j.heares.2010.08.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 08/10/2010] [Accepted: 08/12/2010] [Indexed: 10/19/2022]
Abstract
The eardrums of all terrestrial vertebrates (tetrapods) are connected through Eustachian tubes or interaural canals. In some of the animals, these connections create pressure-gradient directionality, an enhanced directionality by interaction of sound arriving at both sides of the eardrum and strongly dependent on interaural transmission attenuation. Even though the tympanic middle ear has originated independently in the major tetrapod groups, in each group the ancestral condition probably was that the two middle ears were exposed in the mouth cavity with relatively high interaural transmission. Recent vertebrates form a continuum from perfect interaural transmission (0 dB in a certain frequency band) and pronounced eardrum directionality (30-40 dB) in the lizards, over somewhat attenuated transmission and limited directionality in birds and frogs, to the strongly attenuated interaural transmission and functionally isolated pressure receiver ears in the mammals. Since some of the binaural interaction already takes place at the eardrum in animals with strongly coupled ears, producing enhanced interaural time and level differences, the subsequent neural processing may be simpler. In robotic simulations of lizards, simple binaural subtraction (EI cells, found in brainstem nuclei of both frogs and lizards) produces strongly lateralized responses that are sufficient for steering the animal robustly to sound sources.
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Krützfeldt NOE, Logerot P, Kubke MF, Wild JM. Connections of the auditory brainstem in a songbird, Taeniopygia guttata. I. Projections of nucleus angularis and nucleus laminaris to the auditory torus. J Comp Neurol 2010; 518:2109-34. [PMID: 20394061 DOI: 10.1002/cne.22334] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Auditory information is important for social and reproductive behaviors in birds generally, but is crucial for oscine species (songbirds), in particular because in these species auditory feedback ensures the learning and accurate maintenance of song. While there is considerable information on the auditory projections through the forebrain of songbirds, there is no information available for projections through the brainstem. At the latter levels the prevalent model of auditory processing in birds derives from an auditory specialist, the barn owl, which uses time and intensity parameters to compute the location of sounds in space, but whether the auditory brainstem of songbirds is similarly functionally organized is unknown. To examine the songbird auditory brainstem we charted the projections of the cochlear nuclei angularis (NA) and magnocellularis (NM) and the third-order nucleus laminaris (NL) in zebra finches using standard tract-tracing techniques. As in other avian species, the projections of NM were found to be confined to NL, and NL and NA provided the ascending projections. Here we report on differential projections of NA and NL to the torus semicircularis, known in birds as nucleus mesencephalicus lateralis, pars dorsalis (MLd), and in mammals as the central nucleus of the inferior colliculus (ICc). Unlike the case in nonsongbirds, the projections of NA and NL to MLd in the zebra finch showed substantial overlap, in agreement with the projections of the cochlear nuclei to the ICc in mammals. This organization could suggest that the "what" of auditory stimuli is as important as "where."
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Affiliation(s)
- Nils O E Krützfeldt
- Department of Anatomy, Faculty of Medical and Health Sciences, University of Auckland, PB 92019 Auckland, New Zealand
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Hausmann L, von Campenhausen M, Wagner H. Properties of low-frequency head-related transfer functions in the barn owl (Tyto alba). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2010; 196:601-12. [DOI: 10.1007/s00359-010-0546-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 05/26/2010] [Accepted: 06/03/2010] [Indexed: 11/30/2022]
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Abstract
This paper is a comparative study of auditory-nerve morphology in birds. The chicken (Gallus gallus), the emu (Dromaius novaehollandiae) and the starling (Sturnus vulgaris) were chosen as unspecialised birds that have already been used in auditory research. The data are discussed in comparison to a similar earlier study on the barn owl, a bird with highly specialised hearing, in an attempt to separate general avian patterns from species specialisations. Average numbers of afferent fibres from 8775 (starling) to 12¿ omitted¿406 (chicken) were counted, excluding fibres to the lagenar macula. The number of fibres representing different frequency ranges showed broad maxima in the chicken and emu, corresponding to hearing ranges of best sensitivity and/or particular behavioural relevance. Mean axon diameters were around 2 microm in the chicken and starling, and around 3 microm in the emu. Virtually all auditory afferents were myelinated. The mean thickness of the myelin sheaths was between 0.33 microm (starling) and 0.4 microm (emu). There was a consistent pattern in the diameters of axons deriving from different regions. Axons from very basal, i.e. highest-frequency, parts of the basilar papilla were always the smallest. In the emu and the chicken, axons from the middle papillar regions were, in addition, larger than axons innervating apical regions.
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Affiliation(s)
- C Köppl
- Institut für Zoologie, Technische Universität München, Lichtenbergstrasse 4, 85747, Garching, Germany.
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MICHELSEN AXEL, ROHRSEITZ KRISTIN. SOUND LOCALISATION IN A HABITAT: AN ANALYTICAL APPROACH TO QUANTIFYING THE DEGRADATION OF DIRECTIONAL CUES. BIOACOUSTICS 1997. [DOI: 10.1080/09524622.1997.9753341] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Abstract
The major cues for the sound localization are the interaural differences in the timing and intensity of acoustic information. This poses a difficult coding problem for animals with relatively small heads, such as birds, because interaural time differences (ITDs) would have a small range and magnitude and interaural intensity differences (IIDs) would be significant for only high frequency sounds. It has been suggested that this coding problem is mitigated in birds by an enhancement of ITDs and IIDs resulting from the acoustic coupling of the two middle ear cavities through an interaural canal. In this report, the functional ITDs for sounds at different azimuthal locations were recorded in young chicks, and the contribution of middle ear acoustic coupling was evaluated. ITDs were calculated from simultaneous cochlear microphonic (CM) recordings evoked by pure tone stimuli. These effective ITDs were larger than predicted by the physical separation of the two ears, and this enhancement was more pronounced at low (0.8 and 1 kHz) than at high (2 and 4 kHz) frequencies, reaching maximum values of approximately 180 and 100 microseconds, respectively. The amplitude of the CM also varied as a function of sound source location. This variation was as much as +/- 30%, even for the low frequency tones. This suggests that IID cues are also available to the chick. To determine the contribution of middle ear acoustic coupling to the timing and amplitude of the CM response, the CM in one ear was measured prior to, and following occlusion of the contralateral external auditory canal. The cochlear microphonic from the ear distal to the sound source advanced in time and increased in amplitude when the ear proximal to the sound source was sealed. These effects were more pronounced for low frequency sounds. These findings confirm that acoustic coupling of the middle ear cavities plays a role in enhancing sound localization cues in the chick.
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Affiliation(s)
- R L Hyson
- Virginia Merril Bloedel Hearing Research Center, University of Washington School of Medicine, Seattle 98195 USA
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Abstract
When two tones are presented to the ear, distortion products are generated which are lower in frequency than the presented (primary) tones. We studied the responses of neurons from the inferior colliculus of the cat to small frequency modulations (FM) of primary tone combinations which gave rise to distortion products within the neuron's response area. Neural discharges were modulated in response to the FM of the distortion product in a similar manner to modulation of discharges by FM of a pure tone to which these neurons were sensitive. However, very shallow, neurally-insignificant FM of high-frequency primaries could be transposed into significant FM of lower frequency distortion products. Because the sensitivity of a low-frequency neuron to a transposed FM exceeds that of neurons sensitive to a single tone with the same FM, the effect is termed hyperacuity.
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Affiliation(s)
- K I McAnally
- Department of Physiology and Pharmacology, University of Queensland, St. Lucia, Australia
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Avian interaural canal enhances interaural delay. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 1988. [DOI: 10.1007/bf00612515] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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