I photographed this Rufous-winged Buzzard near Ban Arunothai, along the way up to Doi Angkhang. The bird was perching right on the roadside ignoring all the cars that were passing by. It looked overall darker than normal Rufous-winged Buzzard I usually see, especially on the underparts. Instead of having mottled brownish-grey belly and white undertail coverts like the one here, this individual has strong rufescent underparts including undertail coverts!
At first I thought this might be a ‘rufous morph’ but after talking to Dr. Chaiyan Kasorndorkbua, I got to know that older birds tend to become darker and more rufous. So I guess this one is a really old bird.
Very typical setting for this Indochinese specialty and a typical sight while driving up Doi Angkhang!
A couple more shots of the same bird while it was perching on the roadside.