“I was able to observe and record some of the calls of House Swifts (Apus affinis subfurcatus). These are extremely sociable birds and often in large flocks. This was a small flock of 15-18 birds that was fortunately low enough to capture reasonable audio recordings.
“Above is the edited audio and below the sonogram and waveform, a recording of the typical ‘rattling thrill’ (Wells 1999) that is so common of the species. As the sonogram shows, it is made of many birds calling out at the same time, and the calls ascend and then descend.
“You may need to increases the sound volume to hear them well. I was stationary and the birds came and went, hence giving the impression of approach and departure in the recording. These calls are often used when in a flock high up in the sky interacting, especially when mating, and also when at nests.
“Above is the edited audio and below the sonogram and waveform, a recording of the less well noted individual calls of the birds; a piercing or screaming call. These are used intermittently and I suspect they are caution or warning calls.”
Dato’ Dr Amar-Singh HSS
Ipoh, Perak, Malaysia
27th May 2018
Location: Ipoh, Perak, Malaysia
Habitat: Limestone outcroppings at outskirts of the city with secondary growth
