Osprey

The osprey is a large raptor, 50 to 66cm long with a wingspan of 127 to 180cm and a weight of 0.9 to 2.1kg. The wing chord measures 38 to 52cm, the tail 16.5 to 24cm and the tarsus 5.2 to 6.6cm (Wikipedia, general species account).

The only source read for the Bhutan guide gives these measurements. No plumage, range, habitat, diet or breeding information was found, so none is stated, and its occurrence in Bhutan is flagged for checking.