Cinnamon Bittern (Ixubrychus cinnamomeus) is one of the common breeding visitors in northern Thailand. They can be frequently seen while flying over wetlands and rice fields during wet season, but proved to be quite difficult to find when on the ground. This year, I had my first sighting of this species on 2 May 2021 when a pair was seen flying over Mae Faek paddies, while last year, I observed it between 12 May to 30 September 2020.
Adult male Cinnamon Bittern; note all yellow bill and facial skin
Adult male; note facial skin and bill base turn pinkish-red during courtship display
Colour of the facial skin can easily change according to the mood. Here’s the same male while giving a series of soft hooping calls to defend its territory.
The male plumage usually appears largely plain rufous-orange.
However, it also has large black scales on lower neck which are usually hidden by the neck feathers.
Despite the brightly coloured plumage, the male Cinnamon Bittern is, interestingly, more often seen than the female. To my experience, the female is usually more secretive and seldom come out to feed in the open unlike the male. During wet season, I usually see the males walking around in open rice fields looking for various types of food including amphibians, small fish and insects. The females, however, are mostly seen in grassy areas and mostly seen when flushed from dense cover.
Female Cinnamon Bittern has duller plumage with pale buffish spots on wing coverts and dark streaks on the neck.
Female-type plumage appears to be quite variable. This individual has much bolder streaks on the neck compared to the previous bird.
This bird has a quite unusual plumage. I think it’s an adult female although it has pale buffish spots on the scapulars similar to juvenile plumage. In juvenile plumage, the pale markings on mantle and scapulars should be denser and more scale-like.
A pair of adult male (upper) and female (lower) Cinnamon Bitterns
At the time of writing this post (2 July 2021), I haven’t seen any fledged juvenile yet. Sightings of juveniles would normally peak in autumn, around September-October. Similar to the female, juvenile plumage is also quite variable. Some strongly marked individuals are often misidentified as the similar but much rarer Von Schrenck’s Bittern. The best way to identify these 2 similar species is by the colour of the primaries, i.e. rufous in Cinnamon Bittern and dark grey in Von Schrenck’s Bittern.
A young juvenile; note the overall bold buffish spots and rufous primaries which can sometimes be seen even in closed wings
A paler individual with overall rufous-buff tone to the plumage
As the pale fringes wear off, the juvenile can appear darker overall.
A strongly rufous juvenile, possibly a male; note the plain rufous greater coverts, tertials and flight feathers unlike the previous two birds
Being young and naive, the juveniles are more often seen in the open than the adults.
Just for fun, can you find the bird in this picture?
ayuwat 
Never seen such detailed description , field notes
Thank you for your work
Never seen such detailed description , field notes
Thank you for your work
Thank you!
Hi, wonderful observation and photos
I’m more curious about what photography gear you used for these pictures
Thanks, Saswat. I mainly use Canon 5D II + Tamron 150-600 mm II