Figure 1. Calls of the Blue Ground-Dove. The sound was band-pass filtered (200 Hz, 800 Hz) and amplified. The spectrogram DFT size and window size were set to 2048 samples (Raven Pro Software).

See fig. 2 for details of section with label A.

Figure 2. Details of section "A" from fig. 1.

The vocalization of the Blue Ground-Dove can be a series of pairs of calls, like the pairs (1,2) (1,2) in our example.

See fig. 3 for details of section with label B.

Figure 3. Details of section "B" from fig. 2.

The calls of the Blue Ground-Dove sound soft, because sound onset (shown here) and offset are smooth. In the example, we see a gradual rise of sound amplitude over at least 30 ms, from 19.375 s to about 19.405 s. An abrupt rise would result in an initially much harsher sound.