the white nest ,the entire nest is made of saliva is most sought after. The other are the A. Maxima which produces the same white nest but the nest is mixed with feathers which need to be removed before marketable, the C.Esculenta also harvested in cave area which with small amount of white saliva in it . To differentiate them is not easy, most differentiation is thru identifying of nest.
The AF is dark brown with a lighter brown on its rump. Its smaller in size (110-120cm)compared to House swift. House swift which has a white color rump which the nest is make up of twig and grass, that is why some called it grass nest swiftlet. The flying patent of both also different. It is quite obvious the flying patent especial while gliding, flipping of wing, diving,etc
are easily identifiable and could be differentiated. Spend some times looking up the sky in no time you will get what I mean. (between House Swift & Swiftlet)
Current all swiftlets that we are breeding here are from the sub-species from Jawa (a.fuciphagus-fuciphagus) as the farming history there could be traced back early 19th century. This is so called domesticated birds which are not afraid of human. That is why when a bird test call is made all swamed to the sound.
Swiftlet has weak legs they can't perch but they have strong claws, they can't lock their elbows so this makes them unable to stand. As their wing are longer than their tails so flipping the wing on the ground is impossible. So when swiftlets landed on the ground they are unable to fly again. Therefore in the farm planks are vitically installed for the swiflet to claw.