
Photo: Donald Davesne · CC BY 4.0 (May be cropped or resized)
Hirundo rustica
Habitat
Nest of mud, hair and other materials, taking about two weeks to build; old nests are highly prized
Size
17–19cm including 2–7cm outer tail feathers
Wingspan
32–34.5cm
Weight
16–22g
The adult male barn swallow of the nominate subspecies is 17 to 19cm long, including 2 to 7cm of elongated outer tail feathers. It has a wingspan of 32 to 34.5cm and weighs 16 to 22g (Wikipedia, general species account).
It takes around two weeks for a pair to build a nest from mud, hair and other materials, so old nests are highly prized. The sources read give no range, habitat or diet information for the Bhutan guide, and do not name Bhutan, so none is stated.