The male Baya Weaver (Ploceus philippinus) builds the nest up to the helmet stage, collecting materials and weaving the pieces together. He then gets his mate to approve the structure. Only then will the bulbous egg-chamber and the long pendulous entrance tube be completed. This final stage of building sees both adults participating.
The image by Calvin Chang a.k.a. Deswitch shows the pair bringing strips of grass blades and/or palm leaflets to complete the nest building (above left). That by Jimmy Tan a.k.a. skylark shows the pair hard at work completing the egg-chamber (above right).
Image above left by Calvin Chang and right by Jimmy Tan.
This post is a cooperative effort between NaturePixels.org and BESG to bring the study of bird behaviour through photography to a wider audience.