The active space of red-winged blackbird song
- 314 Downloads
Maximum root-mean-square song amplitude at 1 m from a singing bird ranged from 88.5–93.5 dB SPL (\(\bar X\)± SE = 90.8±0.21 dB SPL).
Close to the source, song attenuates at a rate which closely matches that predicted by spherical spreading (6 dB/doubling of distance) alone. At distances beyond about 30 m, however, excess attenuation becomes important (Fig. 4). The rate of attenuation varies with relative wind direction (Table 1).
Ambient noise level is relatively low in early morning, rises in late morning and afternoon as air turbulence increases, and then drops again in the evening as turbulence decreases (Table 2 and Appendix). Measured on a 4 kHz octave filter scale (center frequency = 4 kHz, octave pass-band = 2.83– 5.66 kHz), noise during one day ranges from 15 dB SPL (at 06∶00 h) to 36 dB SPL (at 11∶00 h), more than a 10-fold variation in ambient sound pressure.
A 3 dB signal to noise ratio is sufficient for detection of song masked by noise in the field (Figs. 5 and 6). Also, redwings are able to detect differences in this ratio as small as 3 dB.
In the absence of wind, the maximum active space of redwing song is about 189 m for a signal SPL of 93.5 dB at 1 m. This distance varies with changes in ambient noise level during the day, and with relative wind direction.
Maximum measurements of active space correspond closely to the maximum distances across 2 individual upland redwing territories. This suggests that redwing song is adapted in its structure and amplitude at the source to communicate a male's presence throughout the extent of his neighbors' territories.
KeywordsActive Space Ambient Noise Late Morning Ambient Noise Level Filter Scale
- B & K
Brüel and Kjaer
signal to noise ratio
sound pressure level (re: 20 μPa)
Unable to display preview. Download preview PDF.
- Bowman RI (1979) Adaptive morphology of song dialects in Darwin's finches. J Ornithol 120:353–389Google Scholar
- Brackenbury JH (1979) Power capabilities of the avian sound-producing system. J Exp Biol 78:163–166Google Scholar
- Brenowitz EA (1981a) The effect of stimulus presentation sequence on the response of Red-winged Blackbirds in playback studies. Auk 98:355–360Google Scholar
- Brenowitz EA (1981b) ‘Territorial song’ as a flocking signal in Red-winged Blackbirds. Anim Behav 29:641–642Google Scholar
- Brenowitz EA (1982) Long-range communication of species identity by song in the Red-winged Blackbird. Behav Ecol Sociobiol 10:29–38Google Scholar
- Cody ML, Brown JH (1969) Song asynchrony in neighboring bird species. Nature 222:778–780Google Scholar
- Dabelsteen TC (1981) The sound pressure level in the dawn song of the Blackbird (Turdus merula) and a method for adjusting the level in experimental song to the level in natural song. Z Tierpsychol 56:137–149Google Scholar
- Dooling RJ (1980) Behavior and psychophysics of hearing in birds. In: Popper AN, Fay RR (eds) Comparative studies of hearing in vertebrates. Springer, Berlin Heidelberg New York, pp 261–288Google Scholar
- Dooling RJ, Saunders JC (1975) Hearing in the parakeet (Melopsittacus undulatus): absolute thresholds, critical ratios, frequency difference limens, and vocalizations. J Comp Physiol Psychol 88:1–20Google Scholar
- Ehret G (1977) Comparative psychoacoustics: perspectives of peripheral sound analysis in mammals. Naturwissenschaften 64:461–470Google Scholar
- Hassall JR, Zaveri K (1979) Acoustic noise measurements, 4th ed. Brüel and Kjaer Instruments, Inc., Marlborough, MassachusettsGoogle Scholar
- Heinz RD, Sinnott JM, Sachs MB (1977) Auditory sensitivity of the Redwing Blackbird (Agelaius phoeniceus) and Brown-headed Cowbird (Molothrus ater). J Comp Physiol Psychol 91:1365–1376Google Scholar
- Henwood K, Fabrick A (1979) A quantitative analysis of the dawn chorus: temporal selection for communicatory optimization. Am Nat 114:260–274Google Scholar
- Howard RA Jr (1977) Habitat structure, polygyny, and the evolution of upland nesting in Red-winged Blackbirds. PhD dissertation, Cornell University, Ithaca, New YorkGoogle Scholar
- Ingard U (1953) A review of the influence of meteorological conditions on sound propagation. J Acoust Soc Am 25:405–411Google Scholar
- King AP, West MJ, Eastzer DH, Staddon JER (1981) An experimental investigation of the bioacoustics of cowbird song. Behav Ecol Sociobiol 9:211–217Google Scholar
- Marten K, Marier P (1977) Sound transmission and its significance for animal vocalization. I. Temperate habitats. Behav Ecol Sociobiol 2:271–290Google Scholar
- Marten K, Quine D, Marier P (1977) Sound transmission and its significance for animal vocalization. II. Tropical forest habitats. Behav Ecol Sociobiol 2:291–302Google Scholar
- Morton ES (1975) Ecological sources of selection on avian sounds. Am Nat 108:17–34Google Scholar
- Orians GH, Christman GM (1968) A comparative study of the behavior of Red-winged, Tricolored, and Yellow-headed Blackbirds. Univ Calif Publ Zool 84:1–85Google Scholar
- Peek FW (1972) An experimental study of the territorial function of vocal and visual display in the male Red-winged Blackbird (Agelaius phoeniceus). Anim Behav 20:112–118Google Scholar
- Richards DG, Wiley RH (1980) Reverberations and amplitude fluctuations in the propagation of sound in a forest: implications for animal communication. Am Nat 115:381–399Google Scholar
- Sachs MB, Sinnott JM, Heinz RD (1978) Behavioral and physiological studies of hearing in birds. Fed Proc 37:2329–2335Google Scholar
- Saunders JC, Denny RM, Bock GR (1978) Critical bands in the parakeet (Melopsittacus undulatus). J Comp Physiol 125:359–365Google Scholar
- Smith DG (1979) Male singing ability and territory integrity in Red-winged Blackbirds (Agelaius phoeniceus). Behaviour 68:193–206Google Scholar
- Waser PM, Waser MS (1977) Experimental studies of primate vocalization: specializations for long distance propagation. Z Tierpsychol 43:239–263Google Scholar
- Wasserman FE (1977) Intraspecific acoustical interference in the White-throated Sparrow (Zonotrichia albicollis). Anim Behav 25:949–952Google Scholar
- Wiley RH, Richards DG (1978) Physical constraints on acoustic communication in the atmosphere: implications for the evolution of animal vocalizations. Behav Ecol Sociobiol 3:69–94Google Scholar
- Yasukawa K (1981) Song repertoires in the Red-winged Blackbird (Agelaius phoeniceus): a test of the Beau Geste hypothesis. Anim Behav 29:114–125Google Scholar