. Bulletin of the British Ornithologists' Club. [Bull. i976: 96(4)] 14 playback to a pair of a recorded duet, either their own or that of another pair, or when a second pair was present. Birds duetting in the canopy, often in sight of each other, would invariably approach the tape-recorder on hearing the playback and continue to duet. A similar response to playback of duets occurs in L. barbarus and L. erythrogaster (Thorpe 1972). In one series of L. atroflavus duets, with both birds on the same side of the tape-recorder, the mean reaction time was 145 ±10 (sd) msec and the mean time i
. Bulletin of the British Ornithologists' Club. [Bull. i976: 96(4)] 14 playback to a pair of a recorded duet, either their own or that of another pair, or when a second pair was present. Birds duetting in the canopy, often in sight of each other, would invariably approach the tape-recorder on hearing the playback and continue to duet. A similar response to playback of duets occurs in L. barbarus and L. erythrogaster (Thorpe 1972). In one series of L. atroflavus duets, with both birds on the same side of the tape-recorder, the mean reaction time was 145 ±10 (sd) msec and the mean time interval between duets was 4*45±0' 12 (sd) sec. The frequency/time profile of the first component of a atroflavus duet invariably had the inverted U profile shown in Fig. 1. The general lack of variability in its profile is in marked contrast to the variability found in the duets of barbarus and erythrogaster (Thorpe 1972). The second component (Fig. 1) is a single "clicking" note described by Serle (1965) as "cnook", KHj f\ I A :i f\. Figure 1. Diagrammatic sound spectograms (1-5) of the first component and (6-9) of the complete duet of Laniarius atroflavus (male? dark, female? hatched. 1-5 are taken from separate duet sequences and 6-9 from one duet sequence. and is very similar to that given by barbarus^ although in barbarus two or three such notes are added in response to the first component. It is, however, quite different from the response of erythrogasterâ , which is described as a prolonged snarl in which the frequency range is smaller than in the other two shrikes (Thorpe 1972: 112). The Brown-backed Warbler Cisticola discolor was the most vocal of the birds encountered on the mountain, and duetting was also heard below the forest belt, in grassland near Great Sopo (850 m). Pairs were breeding at all elevations within the forest. Territorial counter duetting between pairs was frequent and regularly occurred in the same locations day after day s
Size: 2518px × 992px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbritishornithologistsclub, bookcentury1900, bookcollec
