
Photo: Vihansith Kulatunga · CC BY-SA 4.0 (May be cropped or resized)
Dicaeum erythrorhynchos
Habitat
Nest opening is a slit
Clutch size
2–3 eggs
Size
8cm
The pale-billed flowerpecker is a tiny bird, 8cm long, one of the smallest birds in most parts of southern India and Sri Lanka. The nest opening is a slit, and a clutch of two or three eggs is laid (Wikipedia, general species account).
That is all the source read for the Bhutan guide gives. It describes southern India and Sri Lanka and does not name Bhutan, so the species' occurrence there is flagged for checking.