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Temporal coding in the moth ear was inferred from the response of the auditory receptor to acoustic stimuli with different temporal characteristics. 1. Determinations of the threshold with different stimulus pulse durations showed that the moth ear behaves as an energy detector with a maximum time constant (the integration time) of 25 ms. Pulse durations(More)
As animals vocalize, their vocal organ transforms motor commands into vocalizations for social communication. In birds, the physical mechanisms by which vocalizations are produced and controlled remain unresolved because of the extreme difficulty in obtaining in vivo measurements. Here, we introduce an ex vivo preparation of the avian vocal organ that(More)
Previous studies of hair cell regeneration and hearing recovery in birds after acoustic overstimulation have involved relatively few species. Studies of the effects of acoustic overexposure typically report high variability. Though it is impossible to tell, the data so far also suggest there may be considerable species differences in the degree of damage(More)
Songbirds vocalizing in helium show a change in the spectral quality of their vocalizations. This effect is due to an increase in the speed of sound in helium that in turn alters the resonance properties of the vocal tract. Here, this approach is extended to a psittacine, the budgerigar (Melopsittacus undulatus), whose syringeal anatomy and innervation(More)
The detection of signals in noise is important for understanding both the mechanisms of hearing and how the auditory system functions under more natural conditions. In humans, the auditory system gains some improvement if the signal and noise are separated in space (binaural masking release). Birds with small heads are at a disadvantage in separating noise(More)
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(More)
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(More)
Hearing thresholds of a great cormorant (Phalacrocorax carbo) were measured in air and under water using psychophysics. The lowest thresholds were at 2 kHz (45 dB re 20 μPa root-mean-square [rms] in air and 79 dB re 1 μPa rms in water). Auditory brainstem response measurements on one anesthetized bird in air indicated an audiogram with a shape that(More)
The source characteristics of biosonar signals from sympatric killer whales and long-finned pilot whales in a Norwegian fjord were compared. A total of 137 pilot whale and more than 2000 killer whale echolocation clicks were recorded using a linear four-hydrophone array. Of these, 20 pilot whale clicks and 28 killer whale clicks were categorized as being(More)