Abstract
Vocalizations with prevailing energies <4 kHz are nearly omnidirectional while those with energies mainly >5 kHz are directional with a reduction in sound pressure level of up to 20 dB behind and below the bird. The beak opening angle can act as a volume control for high frequencies. Turdus merula vocalizations, eg the hawk alarm seee call, can be beamed toward target individuals, whereas low frequency vocalizations, eg the chook call, expressing mild arousal, can be used towards individuals in unknown locations. -from Authors
| Original language | English |
|---|---|
| Journal | Ornis Scandinavica |
| Volume | 21 |
| Issue number | 1 |
| Pages (from-to) | 37-45 |
| Number of pages | 9 |
| ISSN | 0030-5693 |
| Publication status | Published - 1. Jan 1990 |