A behavioral test of presbycusis in the bird auditory system

Absolute auditory thresholds were determined behaviorally in European starl ings (Sturnus vulgaris) between the age of 6 months and up to 13 years usin g a GO/NOGO procedure. The thresholds that we observed in individual starli ngs over a time period of 11 years showed no systematic increase over time. When comparing young starlings (age 6 to 12 months) with old starlings (ag e 8 to 13 years), we discovered no substantial age-related hearing loss. In the frequency range from 0.5 to 4 kHz, the thresholds of old subjects were on average increased by 1.5 to 3 dB. For frequencies of 6 and 8 kHz, the m ean threshold increase of old subjects was 6.1 and 4.9 dB, respectively. Th is demonstrates excellent hearing in subjects that had lived on average mor e than five times the starlings' demographic life span of 22 months. This r esult is discussed with respect to the large threshold shift usually found in aging mammals and to differences between the bird and the mammalian audi tory system. (C) 1999 Elsevier Science B.V. All rights reserved.