“About a week ago I was in my condo looking at Climbing Fig (Ficus pumila) (still in juvenile form) which was creeping up a Wild Cinnamon (Cinnamomum iners). Then I heard the familiar drumming sound of the Sunda Pygmy Woodpecker (Dendrocopos moluccensis) which went on for a long time. As I looked up to locate the source, I discovered the bird near a nest hole which appeared to have been freshly excavated. There were many scars on the trunk apparently made by the woodpecker when it drummed.
“Knowing the law of physic, it is interesting to note that it is not easy, if not impossible, for an animal to move the head repeatedly at such a high speed. I therefore decided to find out at what speed the woodpecker was striking the tree trunk.
“The sound track from the video was extracted. It was then opened in ‘Sonic Visualiser’ to show the waveform of the sound (above). This software is similar to the Audacity in certain ways. But it has the advantage of showing the time scale in better precision.
“Zooming in to a suitable range of the sound track, the waveforms show spikes clearly, each representing the sound made by the woodpecker as it strikes the trunk.
“Between the interval A & B marks in the picture (duration of 0.83″ betwen 0.27″ and 1.1″), there are 21 strikes. This works out to be 21/0.83 or 25.3 strikes per sec. Pretty amazing!
“Another video which I recorded later shows the woodpecker came visiting the nest. It was not clear whether there were already chicks in the nest:
Sun Chong Hong
14th March 2014