Most guide books have listed this bird as one species i.e Halcyon chloris. Robson (2007) has however divided this kingfisher to a number of subspecies. Here are the subspecies described:
i) Todiramphus chloris - armstrongi (description: blue above with turquoise wash, whitish collar etc).
ii) Todiramphus chloris - humii (description: bluer above).
iii) Todiramphus chloris - davisoni (description: smaller, blackish-green head-sides).
Robson (2007) further explained that T.c armstrongi is wide spread while T.c humii can be found from Myanmar, South Thailand southwards and T.c davisoni is from Coco Island. I will show some photos of the various collared kingfishers here and let you decide which region they are originated:
The top photos could be from the armstrongi subspecies. The photos were taken at Kampung Nelayan, Tanjung Dawai, Kedah - Feb 2012.
This could be from the humii subspecies. The photos were taken at a mangrove area in Merbok Forest Reserve, Kedah - Feb 2012.
Could this be from the davisoni subspecies? Photos were taken from Teluk Air Tawar IBA - Jan 2012. A much better photo of this subspecies can be viewed at http://www.birdway.com.au/.
The tinge of brownish on its sides may suggest that it could be a juvenile. Image was taken at Air Itam Dalam in December 2014.
HAPPY BIRDING !!