Table 1.
Hyoid displacement measured as three distances, beak gape and caudal displacement of the trachea during call production. LV, distance between larynx and second vertebrae; LH, distance between larynx and the dorsal edge of the beak-skull transition. `Cornua' refers to the distance between the most ventral points of the left and right cornua of the hyoid apparatus (see Fig. 1).
| Bird | Call type/duration (ms) | LV (mm) | LH (mm) | Cornua (mm) | Beak (mm) | Trachea (mm) |
|---|---|---|---|---|---|---|
| 1 | tet | 2.3±0.8 | 2.5±0.8 | 4.3±1 | 0.3±0.3 | 1.8±0.8 |
| <100 | N=10 | N=10 | N=10 | N=12 | N=8 | |
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| DC | 2.4 | 3.4 | 4.0 | 0.6 | 1.3 | |
| 180 | N=1 | N=1 | N=1 | N=1 | N=1 | |
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| 2 | tet | 1.4±0.7 | 2.2±0.8 | 2.4 | 0.3±0.1 | 1.8±0.6 |
| <100 | N=7 | N=7 | N=1 | N=7 | N=3 | |
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| 4 | tet | 2.2 | 3.3 | 3.8 | 0.1 | 1.1 |
| <100 | N=2 | N=2 | N=1 | N=2 | N=2 | |
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| DC | 1.3±0.5 | 3.0±0.6 | 3.7 | 0.8±0.5 | 1.3 | |
| 140–180 | N=6 | N=6 | N=2 | N=6 | N=2 | |
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| 5 | tet | 1.9±0.8 | 3.1±1.7 | 3.5 | 0.8±0.4 | 1.5±0.1 |
| <100 | N=4 | N=4 | N=2 | N=4 | N=3 | |
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| DC | 1.7±0.8 | 3.4±1.0 | 4.4 | 0.8±0.6 | 1.6±0.4 | |
| 140–180 | N=7 | N=7 | N=2 | N=7 | N=7 | |
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| 6 | tet | 1.1 | 2.1 | 2.3 | 0.3 | 1.3 |
| <100 | N=2 | N=2 | N=1 | N=2 | N=1 | |
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| DC | 1.2 | 2.5 | 3.2 | 0.9 | 1.3 | |
| 140 | N=2 | N=2 | N=1 | N=2 | N=2 | |