“There is a matured trumpet tree (Tabebuia rosea) about 15 m tall outside my apartment. Garden birds such as Spotted Dove (Streptopelia chinensis), Olive-backed Sunbird (Cinnyris jugularis), Blacked-naped Orioles (Oriolus chinensis) and Common Flameback (Dinopium javanense) frequently visit this tree partly because of the shade provided by the canopy. Very often, I am alerted to their presence by the calls they make. I can observe them closely at eye-level from one of my bedrooms. The tree is so near that sometimes the leaves are within reach.
“Recently, there has been an increase in audible activities of some Black-naped Orioles here, perhaps they have a nest somewhere around. I can hear them singing practically throughout the day. However, one of the orioles seems to sound rather hoarse, very different from the melodious calls that I am familiar with. It sounds like the bird is having a sore throat. Perhaps it is suffering from the bird flu? I wonder if there is any birder who came across such similar situation?
“Attached is a sound file HERE which I have compiled to compare the normal and hoarse sounding vocalisations. There are two different type of calls, which I named them as Call 1 and Call 2 respectively (see oriole calls comparison.jpg above, which helps to visualise the sound). The normal sounding Call 1 is followed by 2 similar hoarse sounding ones while the normal sounding Call 2 is followed by a hoarse one.
“A visualisation of the sound file in sonogram (in colour) is shown in the sonogram above.
“I have also a short video recorded through the window grille where you can watch and hear the hoarse Call 2 once (top). It was made by an oriole not in view.”
Sun Chong Hong
Singapore
8th March 2011
