Pied Fantail in partial moult

This image by Myron Tay a.k.a. myrontay shows the Pied Fantail (Rhipidura javanica) with its distinctive long, fan-shaped tail held open. It was photographed
at the Singapore’s Chinese Garden. The bird was actively hunting for insects, fanning its tail and raising and lowering its wings to flush them out into the open.

Fantails are a delight to watch. They are lively, sometimes acrobatic, often approaching human observers to observe as they are being observed.

Note that there are 11 tail feathers (rectrices). As tail feathers are paired, with one member of each pair on each side of the tail, with no feather in the middle, obviously one feather has undergone moulting.

Moulting involves a new feather pushing out the old one from its follicle. So the bird had lost one tail feather. But a new feather has yet to be replaced. Moulting of feathers usually takes place one at a time and nearly all birds undergo partial moulting. Complete moulting is when all the feathers are replaced at the same time. But then with complete moulting, the bird is at a disadvantage as it is unable to fly.

This post is a cooperative effort between NaturePixels.org and BESG to bring the study of bird behaviour through photography to a wider audience.

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